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This is all good, but the reality is we'll not have enough renewables any time soon: https://en.m.wikipedia.org/wiki/World_energy_consumption

We should seriously consider solar geo-engineering. Not as the ultimate policy but to buy time.

I really hope not. We don't even know all consequences of geo-engineering. Well, we know it will lower yield of crops on which we depend to feed ourselves.

Future is green or none at all.

We already did geoengineering in form of burning fossils. Reversing this is also geoengineering.
Why not both - our current "forward" momentum is increasing greenhouse gases and, even if we switch fully to renewables with minimal carbon footprint in a very short time-frame, that momentum will continue to have effects. If we apply the "backward" momentum and start removing carbon while also switcing production to green, it should stop the negative effects more quickly.

Of course, I'm all for thorough planning and extensive, well-funded and organized research first - unfortunately, we can't seem to start doing one of these things seriously, let alone all three...

Removing CO2 is not geoengineering in my book. That is reversing what we did and I'm all for that.

Geoengineering is for example emitting particles to atmosphere to lower amount of sunlight hitting earth. This will cause sky to change color, lower yield of crops and possibly other unknown consequences. That I would rather live without. That is last resort think, not first think to do.

We don't even have carbon tax, plane fuel is not taxed etc. and we already talk about geoengineering. This is crazy.

If carbon emissions dropped to zero today, there is enough carbon in the atmosphere to permanently raise the temperature and potentially enough to kick off nasty positive feedback loops like permafrost methane.

Assuming we could hit zero today is of course wildly optimistic. Even reaching an equilibrial state of carbon inflow and carbon outflow would mean approximately halving emissions, rather than tinkering around the edges.

> we know it will lower yield of crops

that is true only for one kind of geo-engineering: emulation of volcano eruption, and that's indeed not the kind of geoengineering we need. What we need instead is a much finer control over weather to prevent +35 and -20 in cities, drive more water to deserts, and make arctic warmer without melting all of greenland ice sheets.

The way around that is to use particles that block/reflect EM radiation that is not useful to plants. For example, glass or silicon gel.
You are being misled by the graph. Here is why:

https://physicsworld.com/a/a-gross-miscalculation/

So basically the chart is based on fuel consumption not actual energy output. Most fossil fuel consumption is inefficient to the tune of about two thirds of the input fuel being wasted. So the graph down-plays the contribution of renewable sources and nuclear by a factor of about 3x in terms of substitution for fossil fuel sources.
Not debating on what the US govt should do- I think Mr Gates should seek funding elsewhere if the govt is not going to be a cooperative player. EU is both interested in reducing the effect of man made climate change and of course in new energy technology
The article mentions traveling wave reactors and molten salt reactors being developed by Terra Power. Any relationship or synergy between these two, or are they orthogonal efforts?
I suppose there would be some synergy in general nuclear knowhow, fuel supply (that is, making available a supply of HALEU or RgPu which is not something the current global nuclear supply chain is providing) and maybe in terms of reprocessing. But the reactors themselves are quite different.
It appears that the link is broken
Something I have been thinking about for years: black attracts heat, right? So why do we not have a worldwide initiative to turn anything that is black to white. Primary uses I am thinking are roofs of houses, and pavement on streets. I remember as a kid painting roofs on my Dad's commercial properties in Florida with reflective paint in order to reduce cooling costs of the properties, which ended up working pretty well.

If climate change really is the threat they say it is, why are we not starting with the simple and obvious solutions first that are super easy to deploy/implement?

Increasing the albedo is one geoengineering strategy that is being discussed regularly. But it doesn't help with other negative aspects of increased CO2 concentrations like ocean acidification.
Do you have any idea how much surface there would be to cover outside of your own backyard for this to be effective ? Are you aware that 1/3rd of the Earth's surface is covered with snow at some point of the year but that snow cover has been declining for decades ?

It truly boggles my mind that you think painting stuff white is the first step to take to take on climate change.

Part of the problem with climate change is that it's too big for anyone to intuitively comprehend. The scope of the disaster (both in timescale and magnitude) is beyond anything humans deal with in their everyday lives, so laypeople are prone to unhelpful observations.
>If climate change really is the threat they say it is...

When can we stop couching our discussion of climate change with clauses like this?

Also, the UN has some numbers on what happens if we increase the albedo of the planet. IIRC, the issue is that almost nothing we do can counteract the loss of albedo from the melting icecap.

I think it helps to understand that only 0.37% of the world's land mass is artificial covering [0]. It makes sense that counteracting the loss of albedo from the melting icecap would be difficult as that would imply drastically increasing the artificial covering while making up for the loss of albedo from what is removed during the process.

[0] https://en.wikipedia.org/wiki/Land_cover

When the climate change has actually happened.
But obviously not to the degree that something dramatic has happened to the world. And a lot of assumptions presumably go into that chart, that are not shown on the chart.

Anyway, I don't want to discuss climate change. Just saying there is no dramatic impact yet - once there is, maybe the language will change...

Due to the gradual nature of the change to the climate in comparison to the average human lifetime and the shifting baseline of people's perceptions, many people will never acknowledge that there has been a dramatic impact.
Some people... So what. Some people actually believe in flat earth theory.
That doesn't seem a bad idea - it is like polar sea ice reflecting heat. However, you'd need to calculate what the benefit would actually be and compare that with the impact of suddenly manufacturing and applying a lot more paint. It might be worth it, it might not.
Actually some places are already working in those solutions as well, like basically painting roads white, and it has been proved that in those areas it's not as hot in the summer so there is less power consumption for AC. (see https://www.cbsnews.com/news/los-angeles-is-painting-some-of...)

However, that is still very expansive, and you need to paint a lot of surface areas (counting those that you can even paint) for it to make a significant difference (in world-wide terms).

If you have a white roof on your house, you need more heating in the winter. Does that help?

> If climate change really is the threat they say it is,

If you're not past the "if" stage... you're not worth talking to.

Bill Gates gets it. We need to step on the gas and deploy boatloads of wind, solar, nuclear, batteries, pumped hydro, long-distance transmission, energy efficiency measures, CCS, demand response, and whatnot.

Yes, it will cost a lot. But leaving our children with an increasingly hostile planet isn't a tenable option either (and one which will be even more expensive as well).

> We need to step on the gas

Nice metaphor...

Really nice, because a ramp up in mass production of these things causes a lot of emissions that will take 50+ years to recover from.
In current Formula 1 parlance; we need to increase our torque demand.
How could be people convinced about importance of this if it doesn't or won't impact them enough?

Yes, "think about our children" is good, but in the end people are still selfish and will think that it's not their problem.

> How could be people convinced about importance of this if it doesn't or won't impact them enough?

As engineers, I feel it's our responsibility to make environmentally friendly solutions that are simply more economically viable than the unclean/unsustainable alternative. I'm working on the oceanic shipping industry myself.

One thing that might help is that longevity research is going on well. Hopefully in 10-20 years it will produce enough results for the general public to start believing that saving the Earth is not just about their children.
That's one of the most important jobs of a politician. Make the hard decisions and convince people that they are needed, even if they don't see it right now. Politicians who don't do that don't do their job. And yes, that means we are in the West (and probably elsewhere) in a veritable political crisis. Not because we have some nutjobs run around "it's all a myth! we don't need to do anything!" but because politicians don't work anymore against it and instead take the lazy path to votes and just agree with it, even if the long-term consequences will be disastrous for humanity.
These initiatives will create a lot of jobs: engineers, administrators, electricians, construction workers. Many of those in areas that were hit hard by manufacturing moving away.
I meet much more people that use “other people won’t care” as an excuse for not doing anything themselves than I meet people who actually don’t care.

If we just started doing our parts and didn’t worry so much about other people doing theirs we wouldn’t in this mess.

or in other words, the tragedy of commons.
No, it's the tragedy of blaming the tragedy of the commons.
Yes, saw recently on HN (and often IRL) "no point recycling when industry ...", and "we'll never best 10% domestic recycling, why bother".

In UK councils quote 50% recycling rates. And that's with most supermarkets still producing food in unrecyclable packaging.

At the risk of injecting extra negativity into the thread: what about the recent revelations that a lot of (if not most) recycling is really shipping the trash to poorer nations to be dumped there?
>"councils quote"

Yeah ... I've not investigated that yet. But I have seen some of our local recycling facilities and they seem to be operating rather than secretly filling shipping containers.

It does trouble me visiting my town's rubbish dump, there is so much usable stuff in the skips, so much waste.

Presumably China now refusing other country's trash is shedding new light on these issues.

I think we have to fix our entire economic systems in order to solve this, and I don't think that's going to work readily because people will always exploit others for financial/political gain at the expense of the environment. We're going to have to seriously curtail individual freedoms that allow people to make excessive use of resources. We can't do that under our current market-based systems.

Take a simple example, fleece fabric is great, cheap, used widely but is a massive source of microplastic pollution - we're going to have to make it expensive, and stop people from throwing it away, and use the income to do proper filtration and recycling.

We're going to need to start treating fraud wrt environmental issues as akin to manslaughter - actually put businessmen in jail who are responsible (knowingly, or unknowingly through negligence) for things like shipping recycling abroad and not confirming it is recycled, or lying about car MPGs, or failing to filter effluent, or allowing runoff to poison water sources, ....

We probably need something akin to a global one-child policy as well. We can't go on increasing population and just expect resources to stretch. Things are going to break much harder with population rates left as they are.

I better stop ... /rant

Hah, don't worry about /rant, I agree with you. In particular wrt. treating environmental fraud issues akin to manslaughter, or at least intentionally causing bodily harm. Because that's what it is, except stretched over time and applying to more people. We have an issue like this close to home - apparently in Poland there are people who offer very cheap disposal of toxic waste. They take that waste and just dump it illegally. I'd like to see them - and those who in full knowledge use their services - to be dragged in front of the courts and jailed.
Yes, in UK too. AIUI we've implemented a system of tracking the waste to the originators, who can't use the excuse "I paid someone" as they are jointly responsible for safe disposal. Waste disposal operatives have therefore to have licenses and domestic users must check the license so they can be assured the waste will be disposed of, use unlicensed operators, get fined. It seems to be working to some extent but as costs for proper disposal increase the "benefits" of fraud for the waste operatives increase too.
This will cost a lot, and this is not even the hardest step. We use energy for electricity, but also transportation, heating, fertilizer production/agriculture, cattle produces GHG, A/C recycling, and what not.

The USA will need to reduce meat consumption, improve public transportation (electric cars if produced at scale will introduce lots of other environmental issues), relocalize industries. They are late to the transition in every domain.

It sounds almost like the disruption necessary to stop global warming is greater than the disruption that would be caused by the global warming.
not sure youre being sarcastic or not... of course the disruption due global warming will be vastly greater than the disruption caused by trying to prevent it, that much is a given
Even if the actual disruption was the same magnitude - if you have control over the disruption, it is much more pleasant one than the one you don't have any control over.
Is it though? Because if humans have control over it, then you can be sure that humans will fight over it. How would the US tell Russia to pollute less?
> How would the US tell Russia to pollute less?

Easy. This has actually been done many times during Cold War.

You do it yourself, and so well, that their citizens will demand it too.

There were many social advances in the West that were imported (usually in a crippled way, but still) to the communist countries (I was born in one). Things like 5-day work week, education improvements, recycling, ecological laws, nuclear proliferation treaties... usually it's very small things, but they do make difference.

But these aren't advances. We're talking about a reduction in quality of life. If we want to reduce the amount of meat people eat because it's a major contributor to climate change, then we'll have to do this through taxes or other such means. If Russia doesn't want to go along with it and has their people eat as much meat as they want then the US would be powerless.

What you suggest only works if you're talking about improving quality of life.

That's not true. Things like ecological or workplace safety regulations are improvements to quality of life at the expense of economic production. Averting global warming also does increase quality of life.

> has their people eat as much meat as they want

It's not healthy to eat that much meat anyway.

> then the US would be powerless

And you shouldn't panic. The US is far from powerless. There are many countries in Europe that for example do not have nuclear weapons. Does it make them dead? No, they continue to live, in fact often with high quality of life.

This worry that you somehow "lose the race", it's such a nonsense (reminds me of "mineshaft gaps" from Dr. Strangelove).

The wealthier will be disrupted relatively more by mitigating climate change as they consume more and have the means to invest. The poor will be disproportionately affected by climate change and are less able to adapt. So even if everyone is worse off overall without mitigation measures against climate change now, the rich would be relatively stronger and so may consider later adaptation preferable to present mitigation.
How is that different from saying that wealthier people are better off, and that this will continue to be the case?
Without climate change inequalities might well increase, but with it they will increase more. I’m also saying that the wealthy may not actually be better off, but they may be relatively better off compared to the less wealthy (e.g. absolute wealth might decrease but relative inequality might increase). For example poorer people may lose land to flooding and go from subsistence to poverty.

Edit: lots of articles about this online, but e.g. http://time.com/5575523/climate-change-inequality/ has some sobering statistics on the likely impact of climate change: e.g. "A 2015 study in the journal Nature projected that the average income in the poorest countries will decline 75% by 2100 compared to a world without warming".

I don't think this is true, unless when you say "the rich" you mean "90% of the population of the West".

Resource consumption happens by a person. There's only so many resources a person will use while being rich. A rich person might consume far more resources than a poor person, but rich people collectively have a much smaller impact than the poor, because there are far fewer of them. This means that if you start tackling climate change and the impact is that food becomes more expensive, then poor people will be far more affected by this than rich people.

I think this probably needs a proper analysis either way, but Oxfam (I realise not a source everyone agrees with) claims 50% of emissions come from the top 10% (this wouldn't just be the "West" - Middle East oil states, rich Asian countries, and rich people worldwide generally all contribute and some in the West probably maintain relatively low carbon lifestyles).

https://theconversation.com/emissions-inequality-there-is-a-... has the Oxfam discussion.

There would be an impact on poor people as you say, but this depends on the exact policies adopted. A study such as the one summarised and linked here: http://bruegel.org/2018/11/distributional-effects-of-climate... would be needed to confirm either way - their conclusion is that climate change mitigation efforts are potentially but not necessarily regressive with respect to wealth distribution.

I don't know any simulations of either scenarios, so I can't tell if the disruptions are comparable or not. It was just my thought at the pretty harrowing and grand scale list of sacrifices we would need to make to stop global warming. Maybe the alternative is worse, I don't know.
not even close
Yep. IPCC AR4 report claims that climate change will cost about 5% of GDP by 2100. That comes to a net present value of about 0.1% of GDP (assuming 3% growth).
Pain now or in the near term always seems far more severe than pain in the further future. Let's suppose that unrestrained global warming will reduce agricultural production to the point where it's no longer viable to grow any meat (or maybe 1% as much). Alternatively we could reduce our meat consumption in the near future by 90%, as part of a broad sustainability program, and be able to maintain that level of meat production indefinitely.

That's the sort of tradeoff we might be looking at.

The difference is that if it's a consequence of nature then people will just accept it. If it's a consequence of politics, then people will fight wars over it. How are you going to stop a sovereign country from growing food that they want? If your trade deals can't offer them more than what your restrictions on them are, then the only option is to intervene by force and institute an authoritarian rule.
Politics isn’t all about coercion. Persuasion and consensus can work just fine. Nobody’s about to start a war over other countries growing too much cattle on their own territory, but as the direct and tangible consequences of climate change become increasingly apparent, I expect the imperative for change to become more broadly accepted. The Paris agreements show that there is broad agreement internationally already.

There’s also no need to draconian enforcement. We can start with a ramped increasing environmental tax on meat products, reductions in farm subsidies on the same, etc. 50 years ago smoking was ubiquitous as a core social and recreational activity, now it’s marginalised. The same could happen to meat eating.

The Paris agreement probably doesn't gave informed consent of the population. I know very few people who are okay with increasing meat prices and reducing their consumption. Finding consensus on this where the people, not just the elite (politicians), agree is going to be difficult. Some countries are just going to disagree. Some are going to use these kinds of talks and rules to play political games etc. How are you going to force a country like China to follow this?

>50 years ago smoking was ubiquitous as a core social and recreational activity, now it’s marginalised.

Meat is the easiest way to get a reasonably balanced diet. There's a reason why we've eaten meat for longer than we've been humans. You're not going to curb that anywhere as easily as smoking. I would even be willing to bet that there are many many many people in the world who would be willing to fight to be able to eat meat.

A lot of this thread leads like the dreams of authoritarians.

What part of "eating less meat / driving less/ relocalize industry" will kill people from heatwaves and cause mass migrations?
Relocalizing industry will certainly cause mass migrations (people will follow the industry).
You're being intellectually dishonest here.

Relocalizing industry is a controlled process, where the direction of the flux of people is known, and housing and infrastructure sizing can be planned and handled, and people won't follow the industry if they can't get acceptable living conditions.

Mass migrations from climate change are due to unexpected meteorological events either directly (floods, heat waves, etc), or indirectly (food scarcity, drinkable water shortages, political instability, etc). The scale, location and time are unpredictable. The people concerned will need to migrate and have to live in unsanitary housing camps.

History suggests that desperate people will attempt to follow the industry regardless of how horrendous the living conditions may be.
When no one can forecast plausible consequences for global warming that have any consistency, it's very hard to have any idea. We have wild apocalyptic visions of the world ending in twelve years, or Mad Max resource scarcity causing the downfall of society, massive sealevel rises wiping out coastal cities. Or it could be an adjustment of a degree or two upward, to bring us in line with the averages for the Medieval Warm Period and other previous climate optimums.

Nor do we have any real understanding of the equilibrium effects of the climate, and many who are pushing climate models are quite obviously ignorant of shifts in global temperature and atmospheric composition on a paleontological scale.

Nobody really knows what the hell is going to happen, and when presented with rank fear-mongering, it's prudent to puzzle yourself with the classic question, cui bono?

Applying the classic question, I'd conclude that the confusion is probably exactly what those who 'bono' the most from inaction are actively creating, and I'd put my money on the many scientists across disciplines who seem to be panicking instead.
When concerned scientists and climate alarmists stop flying in airplanes I might give their warnings of impending dire consequences more credit.

Until the smartest or most concerned folks begin to consistently eat their own dog food I won't either.

I smoke because even though lots of doctors tell me it'll kill me, many of them are smokers too.
Of course I have seen stuff like this. How much seaweed needs to be produced, won't this have other ecological repercussions? Why is this presented as a kill-all-worries innovation?

A much simpler and less crazy solution is simply to have more grass-fed beef. Their manure and body shade can help recreate green pastures in desertic regions, and this would be pretty much CO2-neutral. It's just more expensive, so nobody does it.

Solutions are here, and they're not that hard. People just don't want to implement them because it impacts their profits and abilities to eat tasteless meat 3 times a day for next to nothing.

Growing more seaweed sounds like it would sequester more carbon too.
Just like growing soy to feed beef, like we do now, except that we found out that the cheapest way to do that was to cut down trees in the amazon forest, grow it there and ship it to the US.

Uncontrolled innovation may have unexpected results.

I just want to take a note (and please do not take this as a critique).

Not OP, but when I personally talk on reducing meat consumption for environmental reasons - I do not have animal farts and burps in mind. The process of growing meat requires a lot of resources by itself and at current human population scales we are wasting vast amounts of resources (energy, land, etc.) to grow meat instead of spending those resources to feed ourselves. https://en.wikipedia.org/wiki/Ecological_efficiency#Ten_perc...

IMO, feeding animals unusual foods won't solve the main issue and produce more challenges. It's anecdata (cannot cite anyone), but as much as I've read about ecological farming, problems with animal health and infamous though prevalent use of antibiotics in industrial animal farming is due to the diets of the animals. Animals grown in ecological open farms with habitats natural for the animal grow healthier. But as mentioned in first paragraph - at current human population scales - meat consumption must be reduced rapidly.

P.S. I will digress, but as the problem is insanely big human population (and it's exponential growth), it would be great if people globally won't procreate at such rates.

I think the fact that it isn't cheap shouldn't be that much of an issue (although I know it currently is) because the price we (not even our children) will pay because of climate change would be much higher (in pure economic costs, before we start talking about more moral and environmental costs like animal extinction).

But I think the problem is that people care about today a lot more then they care about tomorrow, or next year (and definitely more then their potential future descendants).

> I think the fact that it isn't cheap shouldn't be that much of an issue...

EDIT: Apologies for the combative tone below, what I'm trying to say is, it's not as simple as monetary cost.

I'm afraid that's looks like first world thinking. For countries still developing lives are literally at stake right now. Rolling back environmental impact means lower economic growth, poorer infrastructure and therefore people dying in poverty.

It's not all bad news on this front. Modi committed India to opening a swath of new coal power stations before coming into office, but has since changed tack with the collapse in the cost of solar energy[1]. Still, this will be new solar capacity and while it's better than more coal it's still environmentally worse than no new energy generation at all.

[1]https://www.ft.com/content/b8d24c94-fde7-11e8-aebf-99e208d3e...

> this will be new solar capacity and while it's better than more coal it's still environmentally worse than no new energy generation at all.

I don’t understand what you’re trying to say here.

Can you elaborate more on this last point?

Do you mean to imply that one approach to the problem is to build no new electricity capacity?

How will we displaced fossil fuel use for transportation, manufacturing, agriculture, and mineral processing if not with new electricity generation?

Or did you mean to imply the world would be better off if India’s poorest continued to suffer in the dark and cold?

All I'm saying is that new capacity to meet an increased demand has an environmental impact even if it is solar.

More broadly my point is we cannot expect developing countries to simply stop developing. That's not an acceptable short term cost, as I pointed out when I said lives are at stake. I'm pointing out some complexities in the issue. How you can get from that to me saying poor people should suffer in the cold confuses me.

Rolling back environmental impact means lower economic growth, poorer infrastructure

This isn't true. It just requires a different development path than Europe and Asia have followed. For example, local power generation can bootstrap a small, isolated economy without requiring massive investments in a nation-wide energy grid. And renewable power (solar or wind) lends itself much better to small-scale deployments than fossil fuel generators.

Yes, this. Cell phones in Africa are a great example. They skipped right over having land lines and went straight to cell phones.
All of those increase environmental impact, they just do it less than historical approaches. Actually rolling back environmental impact is another thing altogether.
The last ten years' experience with renewables has shown that local-scale generation is underwhelming and large-scale deployments are the way to go.

With the exponential recent declines in production cost, most of the cost of solar is now in deployment, not manufacturing the cells. This has made huge desert installations much cheaper per watt than rooftop -- as a result, large-scale installations is where almost all the growth is coming from.

As for wind power, efficiency increases superlinearly with blade length. As a result of this, and improving material science and production/deployment tech, turbines have been getting enormous (Eiffel-tower-sized or more) and no longer fit outside of dedicated wind farms.

As for nation-wide grids, they're are a central part of the solution to solar/wind intermittency (because weather patterns average out over long distances).

A wealthy retiree without kids is going to naturally live for today and not care too much about tomorrow. Suspect there’s plenty of them too.
Apart from being uncharitable, that's just not a reasonable generalisation of human behaviour. Plenty of old people with no relatives have died wealthy wile living very simple lives, giving their wealth to charity. Wealthy retirees with lots of relatives have left all their money to their cat, or whatever. It's just not possible to paint big swathes of humanity with a single broad brush.
I’m not intending to be uncharitable - I agree that there are plenty of people of all sorts. My point is that there will be some people who really don’t care - these could be younger or older, childless or whatever. I am not sure if there is going to be much more than anecdotal evidence on who causes the most damage to the environment and who is likely to change their behaviour due to climate change.

I’m also not saying anybody would be wrong to not care about the future. It’s quite understandable to me someone using their freedom to say f the world, question is if everyone needs to be on board to make necessary changes then how do you achieve that.

In other words the point isn't the (admittedly unjustifiable) generalisation, it's that there are people who are not going to be on board unless they see something in it for them. Could be a wealthy childless retiree, or it could be someone in their thirties with four kids travelling round the world for work racking up air miles for their career to support their family.

A wealthy retiree without kids contributes less to climate change than basically anybody that will have kids. His climate impact stops with him, it doesn't for people with kids.
You can put a price on the planet when you have more than one. Until then, this thinking is absurd.
We do have other planets, relocation will cost roughly $3.75e+15 USD at SpaceX price estimates. IIRC, the global economy is about $1e14 USD/year.
I haven't read the estimates, but that would be relocation only, correct? Assuming that's true, you need to add the costs of terraforming on top of that.
Correct. I kinda assumed the people who moved would build up domed habitats while there until it counted as “done”. Multiply by ten if you want to do it directly, I think?
Why can't we just do that on Earth though? If we're going to live in underground caves , like we would have to on Mars, then why don't we just do it on Earth?
Well, yes, I agree — Antarctica in winter and the peak of Mt. Everest are both vastly more hospitable than Mars, but Mars is there if we want to try it.
We don't "have other planets" in any useful sense. We know there are other planets out there. We're a long way from knowing with even a shred of certainty whether we will ever be capable of relocating to them, let alone when it may become feasible or what it will cost.
So it will only take 37 years in impossibly perfect conditions? Unless people are willing to sacrifice themselves to let others survive this scenario is never going to happen.
That’s literally moving the entire population of the planet — you’d only do that in a very unusual circumstance when most people were going to die anyway if you didn’t leave, and building domes over your cities does nothing to help.

Most people don’t even move more than, what, a hundred miles from where they’re born? Just because I fancy giving it a go doesn’t mean I expect people to go to Mars en masse even if it was free.

But they could if they needed to.

> But I think the problem is that people care about today a lot more then they care about tomorrow

Absolutely, and to change that, you need to ask why this is the case.

There are many reasons for that. Some people are selfish, some are merely short-sighted. This needs to be fixed by changing the mindset.

But to me the (by far) biggest problem is that too many people simply cannot afford to think otherwise.

Climate change in X years means nothing to someone living in, or close to poverty today. "Green" means nothing to someone hungry today, and it would be absurd and apathetic to expect otherwise. And a very large share of the global population today are poor.

This is true, a great deal of good can be accomplished supplying electricity and light and clean water to those who don't have access now. However, the carbon footprint of poor individuals is vastly less per capita than of rich individuals. Every rich person, and you are most likely rich in a global sense, must realize their luck and their lifetime carbon footprint and do their part for decarbonizing, given we are those who emit the most.
This is called "eating your seed corn". Do you go somewhat hungry during winter, and possibly starve now? Or do you eat your seed corn now, and have nothing to harvest later, and certainly starve later?

Our ancestors figured this out. Some of them did starve during winter. But we're the descendants of the lucky and prepared.

Why should the future be any different?

Because the time scale of our situation is different. Those threatened by starvation in winter aren’t the same people who will need the seed corn in spring. That disconnect creates an immediate, imposed suffering on some for the future, anticipated benefit of others.
This is not "eating your seed corn", as that story is about a single resource, and the short-term planning of when to consume it.
> But we're the descendants of the lucky and prepared.

Some of us may be the descendants of those who enjoyed their seed corn during the winter and later reaped the cobs planted by their neighbours.

Given that the poorest are not disproportionately consuming the least-clean energy, I think the poverty issue is minimal.

My parents smoked heavily. Even after the causal connection with lung cancer was well-established. Even though both of them lost their father to lung cancer. Even though their child (me) suffered from asthma, to the extent of being hospitalised. I know addiction is a thing. But there was no sense that those choices were made because of the physical compulsion. There were no attempts to quit. The biggest addiction was mental: a lack of any interest in trying.

I don't think it is helpful to claim we are 'addicted' to high-carbon energy. But whatever the label, there is mind-boggling inertia in the human soul.

Nobody drives a shitty, old, inefficient, dirty gas guzzler because they are addicted to them. They drive them because they can't afford something better.

A solar panel is probably an unaffordable object for at least a quarter of the world's population.

No, but plenty of people drive brand-new, expensive, inefficient gas guzzlers. Poor folks are much more likely to buy a cheap small engine Honda than a 200 cu.in. un-aerodynamic brick. Guzzling gas is expensive.

And the poorest ¼ of the world contribute way way way less than ¼ of our CO₂ emissions.

I guess culture just has to change, so that a gaz guzzler isn't a status symbol. Say, a sailing yacht? Or a telescope in your front yard (for watching the stars, of course, not spying on the neighbors getting it on). Or bling-bling to hang around your neck?

I mean, plenty of ways to show your wealth without it having to be a big FU to the planet.

I'm surprised to not to see inertial storage there

And by no means is the "duck curve" or storage an impediment for adoption. I will not go as far as identifying it as a "core" issue here.

I wouldn't take offense, it's rare for our personal pet technologies to make it into high level documents. These are just Gates' opinion of the best ones after all.

But I would put my money on reflow batteries in the long run if they weren't so far behind, simply the decoupling of storage capacity from power density feels like an engineering perfect storm to me. I was lucky enough that my pet technology made it in =)

Why do you think inertial storage might be superior? I've talked to a fair number of people working on it and it sounds totally doable but I'm unclear that it actually costs less per joule stored or why it would. Granted a flywheel costs less per unit mass and compressed air is cheap, but on a capacity and fabrication basis? Maybe. I don't think I'd call it a shoo-in though and wouldn't invest in it myself.

> Granted a flywheel costs less per unit mass and compressed air is cheap, but on a capacity and fabrication basis? Maybe. I don't think I'd call it a shoo-in though and wouldn't invest in it myself.

Its power and energy density is next to nothing in the industry.

Fabrication, cost on the market? Even most basic flywheels like one used as industrial UPSes can be used right away for grid storage, and be more or less competitive with their high round-trip efficiency.

This just shows that how low a commercial opportunity for energy storage as such is. You need truly monstrous daily variations in energy price to make people put money it it.

By the way, I'm talking about regular steel flywheel, not carbon fibre ones
Indeed, it's not cost but investment. There's a return on investment and it's not just getting rid of carbon. IMHO the easiest way to get the world moving to mostly wind + solar is continuing to lower the cost (unsubsidized). Lower cost of energy enables new use cases.

People seem to be talking about replacing existing energy suppliers with clean ones. Instead we need to be talking about what it will take to generate 10-100X the amount of energy in a few decades and what that would enable. Cheap clean energy enables a lot of things that are currently too expensive/polluting to consider. Countries that manage this will be able to grow more rapidly economically. China looks like it is well positioned for that.

I'm not against nuclear but it will have to come down in price and upfront investment cost for that to have meaningful impact short term. As long as people still dream about maybe being cost competitive with coal/gas one day, the ambitions are simply not high enough. It needs to be vastly cheaper than that. 2-3x would keep it competitive with solar and wind for some decades.

IMHO any price comparisons against current prices are in any case effectively obsolete since those are likely trending down for solar and wind for some time to come. If prices drop by another few double digit percentages, a lot of home owners will do the math and put some solar on their roof.

Carbon capture schemes only make sense when the combined cost of that and keeping the carbon producing stuff they offset functioning is lower. However, even without carbon capturing a lot of these solutions are already problematic in terms of cost and making them more expensive will only speed up their demise. With coal, that has already happened. Natural gas will last a bit longer. However, when wind and solar bids start undercutting these solutions consistently the same will happen there. There's a real chance that remaining gas plants switch to clean sources of gas (i.e. generated using solar/wind/nuclear) when that gets cheap enough.

If we insist on a system with exponential growth the natural outcome will be self destruction, no matter what technology drives this growth.
Why would we settle for the "natural" outcome? Jeff Bezos' dream for Blue Origin is that population and civilization growth can continue in Space, where there's plenty of space and resources.
I just have a hard time with that.

So we make our own planet, a space in the universe we are literally evolved to use, unlivable at some point.

The solution is that we'll magically figure out how to make space, an already hostile environment, livable?

Honestly, space settlement makes for nice headlines for the new ruling class to pat themselves on the back with, but for the rest of us, the natural outcome of unlimited growth is population crash.

> The solution is that we'll magically figure out how to make space, an already hostile environment, livable?

Well, potentially yes, because it would offer us to relieve the pressure on Earth - and the spin-offs from the process of creating space infrastructure and space habitats would be mightily useful for fixing the damage we've already done to Earth.

We didn't break Earth out of spite; before technological civilization, life on Earth was shit. We're breaking the planet out of desire to make our lives better, and we might fix Earth out of the same desire - but only if we get the chance to do it in time.

Not magically, intelligently. Earth exists in Space and is livable, therefore it is possible.

I mean, what else do you want? You don't want the mass death of population crash, nobody has the power to order billions of people to stop wanting things and live in poverty, no one person or group can change government policy of all nations, and we can't keep polluting and increasing energy use at current rates.

There's no way back to an ideal perfect before-time. The only way is forward, and the only way forward without mass death is more technology. I hope someone can work out a way to put the polluting energy intensive things away from where we live.

I just want to point out that "our children" here is literally us and our actual children. It's not some far future hypothetical human population.

If you're under 30, you will probably live to see large swaths of the plant that were previously inhabitable become unlivably hot due to human created carbon emissions. Factor in increased natural disasters, and the effects of a warmer climate on our ability to produce food, this is an incredibly serious problem that will affect you and people you know and love.[0]

Now is the time to act and get involved. Look into groups like the CCL[1] or local Green New Deal organizers. Call your congress-person, get involved at the state and local level. Make this a priority.

[0] http://nymag.com/intelligencer/2017/07/climate-change-earth-... [1] https://citizensclimatelobby.org/

Another option for getting involved is: https://climateaction.tech/

"Technology professionals from many companies — such as Google, Facebook, Tumblr, Etsy, Github, SoundCloud, Lyft and many more — are coming together under the banner of ClimateAction.tech to find ways to accelerate solutions to climate change."

There are lots of interesting projects and support in the slack workspace.

I'd like to know who he thinks the "we" is in this article. Several countries are already using ~100% carbon-neutral electricity and the USA and Europe are progressing rapidly. The main culprits are developing nations and China, so it's "them" who should be doing something urgently and "they" have a whole slew of other problems not covered by Gates' US-centric perspective.

Reasonable approaches would be to bring manufacturing back to countries that use mostly clean energy (oh, and modern approaches to labor and human rights) and to tax imports from developing countries with poor CO2 record heavily until they fix their issues.

So what's the right approach here? Could there be a BDS-like movement on things created with dirty energy?

If there was a "made with renewable energy" certification on products, I'd certainly consider paying a premium and even being inconvenienced into finding them.

Maybe even a version of the better world shopper (https://betterworldshopper.org/) which does exclusively energy grades and then have forward-thinking grocery stores start to to put the grade on the label.

I'd certainly shop at a store with that system at every conceivable opportunity.

You could not be further from the truth. Carbon emissions per capita is way higher in the US and in Europe than in China and India.
China, 7.5 metric tons per person in 2014. Switzerland, 4.3. Sweden, 4.5. France, 4.6. Spain, 5.0. Italy, 5.3. UK, 6.5.

Source: https://en.wikipedia.org/wiki/List_of_countries_by_carbon_di...

Cherry-picking data much?

That same article lists the EU overall at 8.6 and US at 17.

Not sure if you were trying to make a point about China having a greater output than European contries but you missed the USA: 16.5 (metric tons per capita).
AFAIK a fair part of China's emissions are due to the production of goods not bought by Chinese but by Swiss, French, Spanish... nationals. China "decides" to produce, so this country is somewhat "guilty", but let's not neglect its "accomplices".
It's more complicated than that. Emissions in the US, Canada and some European countries are higher (per capita) while some other countries like the UK, Italy, Spain and France are below China. The EU as a whole ranks a bit below China on a per captia basis.

However the other important factor here is the trend line. Most western countries above China in this ranking has a trend line pointing downwards, while China still has a trend line pointing upwards. So if both China and the US continue on their current paths then China will indeed soon surpass the US.

isn't it even more complicated than that?

It would seem that manufacturing would have a significant impact on the figures and a lot of manufacturing has been outsourced to China/India.

So how much of all the stuff that is bought and consumed in the EU/USA is actually produced in China or India?

You are downvoted for apparant racism.

The western world, of about 500 million people, pollute 4x more than China which has 1.2B people.

> apparant racism.

By people who apparently don't even know the meaning of the word.

> The western world, of about 500 million people, pollute 4x more than China which has 1.2B people.

The western world has a much larger population, but I'd like to see you back that claim up with reproducible numbers.

It's a fact that CO2 emissions in China are growing rapidly (per capita and absolutely) while the "western world" is mostly reducing them and has been doing that for many years. Also, we have to rely on China's "official data", which may or may not be correct.

> It's a fact that CO2 emissions in China are growing rapidly (per capita and absolutely) while the "western world" is mostly reducing them and has been doing that for many years.

If it's a fact you should be able to cite a source?

> Also, we have to rely on China's "official data", which may or may not be correct.

The rest of the world is more than capable of monitoring China's emissions using satellite data.

> CO2 emissions in China are growing rapidly

China rapidly tripled their emissions from 2000 to 2010, but after 2011 they have hardly increased at all.

Second graph here: https://www.carbonbrief.org/guest-post-chinas-co2-emissions-...

> Now let us return to why the reported Chinese CO2 emissions growth in the communique is so much lower than our projection in the 2018 Global Carbon Budget. The real reason is not clear, but the problem is an unexplained inconsistency in the coal statistics in the communique. [...] >There is no apparent explanation for these discrepancies. Some people have suggested that China’s statistics bureau is manipulating the data to make coal consumption growth look smoother than it actually is, although there is no direct evidence for this. Whatever the case, the discrepancy over coal means that overall CO2 growth could be as high as around 4% – compared to 2.3% reported in the communique – even before accounting for other sources of uncertainty that we usually include in our analyses. Those factors push the uncertainty range even wider, to -0.4% to +6.7%. ...
https://climateactiontracker.org/countries/china/

Report dated 30 Nov 2018

"China is positioning itself as a global climate leader, and its actions have an enormous impact on global greenhouse gas emissions. Discouragingly, a rise in coal consumption drove Chinese CO2 emissions to a new high in 2017, which will likely be exceeded again in 2018."

European Union: 6.4 tCO2 per capita per year

China: 7.5

And EU is about 500 million people.

Source: 2014 numbers from https://data.worldbank.org/indicator/en.atm.co2e.pc

All that stuff the EU and US buys - where's it made?

It counts toward China's emissions total. Whilst having reduced EU or US contribution comparatively speaking. We globalised manufacturing emissions, and most of them ended up in China.

The simple fact is no one can claim their halo - everyone, everywhere has a part in the solution, and we can find failings to criticise everywhere too.

Maybe Orkney got closest to their get out of jail card, but they're tiny.

> All that stuff the EU and US buys - where's it made?

Not that I disagree, but it is not just Europeans' choice to buy from China, but also Chineses' choice not to sell.

The western world, of about 500 million people

How did you get to that number? EU is about 500 million people, The US and Canada is about 350, Add in any other countries you might consider 'western' and that's another 50-100 million.

How much of the China's footprint is generated for manufacturing stuff for the developed nations?

We may have 100% clean energy locally only because we've outsourced the dirty one.

> We may have 100% clean energy locally only because we've outsourced the dirty one.

We have outsourced it because they have been undercutting local producers in pollution, labor, human rights standards. Therefore bringing back manufacturing and taxing them is a much better solution overall than bringing more extreme measures to our already pretty "green" region.

Wicked consumers! Doubtless Chinese factory workers will find alternative employment in the fields should the need arise.
But because the world must balance the need to eliminate carbon emissions with economic growth

I read this often, and everytime can't help but wonder: must the world really strive for economic growth? Is just stability not enough? Isn't unbridled growth a major cause of the situation we're in now (and not just with respect to climate, but also the wealth of other environmental problesm, even disasters, the earth faces)? Note: these are honest questions. I don't know how econmics really work. Maybe I'm naive, and I perfectly get for some 'more more more' is the key aspect in life. But is that really required?

Growth does not imply consumption of resources. It can simply be technological advances. Finding better cures for cancer is also growth.

Of course mankind would continue without better cures for cancer. But I find it difficult to argue that we shouldn't look for better cures.

But the growth talked is "economic growth"
Curing cancer is also economic growth.
Well, it's easy for us to sit here in the developed world and talk about how the world doesn't need growth.

There are billions of people for whom more of the same means more poverty. When everybody in Africa, South America, Asia, heck even the poorer parts of Europe and North America, has access to clean water, food, education, healthcare, safety, justice etc. we can discuss whether we really need growth.

Growth may not be as needed in our parts of the world, but it sure is for a lot of people.

If there is population growth, there must be economic growth, or every new born mouth makes the rest of the world poorer. That tends to turn people on one another.

Zero population growth is now possible; zero growth in resource usage may be compatible with economic growth.

Economic growth is what allows _very good things_ like education and healthcare continue to improve, and reach a larger number of people, regardless of what you think of material consumerist goods.

These things have made life way better for average people, in many obvious and non-obvious ways, that aren’t the mere collection of material goods. Infant mortality dropping is one obvious effect, but violent crime also decreases for example, the murder rate a few hundred years ago was orders of magnitude higher than now.

I was curious how the homicide rate has changed over time. It’s true as you claimed that it was substantially higher hundreds of years ago, and has been on a steep drop in modern times:

https://ourworldindata.org/homicides

We tend to think of economic growth as a fairly tangible thing with meaning. But, GDP is an industrial era measure. Add up all the shoes, cars & kettles that come out of factories and see if that's growing YoY.

Even then they had to deal with serivices and the other more ethereal parts of the economy (financial services, then and now, are a contraversial element in measuring economies). But, the tagible parts of the economy were big enough that GDP had meaning. If GDP doubled, it meant more food, cars, clothes, steel...

These days, GDP growth, economic growth is a lot more poorly defined. Economists have measures for it, but they can't describe what "GDP doubled" looks like beyond the abstraction used to measure it. It could mean more lawyers/lawsuits/contracts or it could mean more childcare/education. Asking "do we want the economy to grow" is a far less meaningful question than it once was.

To the point in the article though, I do think that we need more energy, not less. In fact, for the future to be futuristic, we need a lot more energy. A side effect of clean energy tech is that we're eploring new paradigms, some with tremendous potential to scale beyond what carbon provided.

Required implies that there is some kind of divine guidance out there, which there isn't, so I suppose we could force humanity to stick to some stable point and not progress any further.

But economic growth is required in the sense that advancing technology requires economic growth. And advancing the human race requires advancing technology, and so on.

The world's population isn't a single entity, so even if one group decides to not pursue economic growth, others still will. The only way to not fall behind is to keep playing.

No, the world doesn't really need to strive for economic growth. IPhones sales not growing year over year is not a disaster for anyone, really. Same for Amazon market share, and so on. And yet: it is, because the system works this way. Growth is god. It's instilled into DNA of every entity working in the capitalism.

We could stop the growing obsession, redistribute the accumulated wealth to the developing nations (perhaps iPhone sales would grow then?), and live happily ever after. Obviously, it's an utopia that's not going to happen.

And yet, it's the only viable way to achieve the emission targets needed for humans to survive on this planet. It's commonly accepted that the best advice you can give someone who wants to reduce her/his carbon footprint is: "consume less". Well, we need to consume less globally.

Since 2000, China has gone from a per capital PPP GDP of $3,000, about the same as the US in the 1880s, to $17,000, about the same as the US in the 1960s or 1970s. In the process, it has added 6 gigatons of carbon output, more than the entire US footprint. Carbon output was the way to a modern, decent life for a billion Chinese. India and Africa are still stuck where the US was a century ago (and their carbon output is correspondingly low). Economic development is necessary for them.
Yes. As others pointed out: without economic growth, population growth makes everyone poorer.

Also, economic growth is not our enemy here (nor is growing energy usage). In fact, properly applied, they're our friends in this problem. The trick is doing more of the helping stuff, and less of the damaging stuff.

I've argued this two days ago, so to not repeat myself: https://news.ycombinator.com/item?id=19897547.

Economic growth is not required for the survival of humanity. Economic growth is just something that wealthy people want so that the can keep or increase their wealth. Again, wealth itself not being vital to the survival of humanity (and many species of animals).
Not many people care about "survival of humanity" in the abstract. What we all care about is not suffering, not dying, and not seeing others suffer and die. And then other things on the Maslov's pyramid. Economic growth is absolutely necessary to achieve that; the default, natural state of humanity is pain and death.
I think the abstraction of humanity as a group of which every human being is part of is something that many people understand. People care about the messages they hear, and most of them still hear a message that says there's no real issue and it's possible to keep living the way they live, and it's possible for everyone to keep living the way they live.

Many people would be okay if the message was: we are all going to have to change the way we live, including the rich.

That's fair. I do too subscribe to the abstraction of humanity as a group.

I guess what I'm saying is that even with climate change, survival of humanity is not at stake. We're unlikely to collapse the climate to the point where no humans can survive anywhere on the planet. What's under threat is survival of our technological civilization, of our ways of life, of our grandchildren. The danger is that a lot of people will suffer greatly and die prematurely, and that the future will only contain more suffering.

"economic growth" just means that we produce more goods and services that people desire, for cheaper.

It it borderline tautological to say that economic growth is "good".

I am not sure how someone can argue against a concept that is almost by definition positive.

> I am not sure how someone can argue against a concept that is almost by definition positive.

People argue against the "more goods" part, on the basis that we have way more stuff than we know what to do with anyway. They're sort of right, but it's throwing baby out with the bathwater. Economic growth also encompasses doing same stuff better, and being more efficient with resource use. From what I've seen, the motivation behind criticism is usually twofold: criticizing greed, and worrying that ever-increasing use will exhaust available resources.

Our enemy might be an economic system based on growth that gives critical political power to groups of people that don't actually care about decreasing carbon emissions.

True, economic growth makes everyone richer. But if we don't find a way to both get economic growth and keep the planet in a liveable state, losing economic growth sounds like a better option than destroying the conditions for human life.

My main fear here is that by fixating on economic growth being bad, we might wind up killing the very engine that gives us technologies to deal with climate change and fix the damage already done. That's why I urge to decompose "economic growth" into pieces, and focus on addressing the parts that are causing trouble.
This is a fair point. But couldn't there be a different engine to technological progress?
Not sure. By their very nature, new technologies improve things, creating economic growth.

Incidentally, I'm not 100% sure whether general economic growth is what powers technological growth directly. I've recently seen arguments suggesting that progress of technology is tied to population growth - which has slowed in the past decades. If this is true, then we're in deep shit - at least until we learn how to convert money into technology instead of researchers into technology. But still, we would neither need economic growth to support population growth to cause technological growth (researchers -> progress), or economic growth to support technological growth directly (money -> progress).

Maybe there's a different economic regime that would let technology to progress and life quality to improve without invoking an explicit concept of "economic growth", but I'm not sure what would that be and whether now is the time to figure it out.

Stability is probably much (much) harder to achieve than either growth or decay.

The measures of economic growth are not perfect but even something like improving a product or service is, in a very real sense, economic growth. Are you asking whether every such improvement should be matched with a corresponding degradation?

Personally, if you're happy with your situation, you shouldn't feel compelled to constantly improve it. But then, if you need or want to protect something (e.g. yourself, your family), a certain amount of {slack / profit / extra resources } is necessary to weather unknown future adversity. And a growing capacity to handle such adverse events is as important as the things you wish to protect and preserve.

> We can do even more. By investing in energy innovations...

Ok. Do it. You promised to give away your entire net worth years ago but you're still worth $100 billion. What's the hold up?

I have to agree with you. Put your money where your mouth is.
I imagine the vast majority of that net worth is tied up in investments and not immediately available to spend. It's not just sitting in his bank account.
The threat of climate change isn't significant enough for him to liquidate his investments?
He's already liquidating them pretty quickly to fund the vast amounts he's ploughing into eradicating polio and malaria, and projects to provide access to clean water, contraception and decent sanitation in the developing world.

It wouldn't surprise me if the linked article doesn't mark the start of a shift in focus to address climate change as well. You may not be a fan of Bill Gates but when it comes to putting his money where his mouth is he has a pretty decent track record in recent years.

Edit to add: When you hold more assets then anyone else there's a limit to the rate that they can be liquidated without completely disrupting the global economy.

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So what you seem to be suggesting is he should spend his entire net worth all in one go right now and then walk away, and if he doesn't he's a fraud? If that's what you mean, it doesn't seem to me to be a very effective strategy when tackling long term problems, especially as new problems keep coming up. No investments means no revenue to tackle new problems.

Do you really think committing everything up front would be a better use of his resources?

At very least he could have its foundation desinvest in non-renewables.
They dis-invested from their fossil fuel portfolio in 2016.

https://www.globalcitizen.org/en/content/gates-divest-fossil...

My bad. I wasn't aware of that. Genuine question, did they also dis-invest in GMO (which tend to be bad for bio-diversity) ?
They do support some GMO research as part of their commitment to improved agricultural output and food security in the developing world. I suppose it's a case of conflicting priorities. They've been into reducing poverty and hunger longer than they've been into environmentalism.

Even then it's not a straight trade-off. GMO can have harmful consequences, but if it reduces the agricultural footprint that's an environmental benefit.

> The organization's stated goal is to inspire the wealthy people of the world to give at least half of their net worth to philanthropy, either during their lifetime or upon their death

https://en.wikipedia.org/wiki/The_Giving_Pledge

You mean that promise? Seems to be coming along as promised. How you doing?

The article lists three important solutions for transition to clean electricity. But there is also a fourth important solution, one that I think HN crowd can help with: demand side management systems. Essentially, this aims to match energy utilisation to energy production.

One idea which needs implementing ASAP is a way to use EV batteries as a flexible storage device, so that you charge the battery when there is a surplus of power, and perhaps release a bit of energy when there is a deficit. To do this in a user-friendly way is not trivial, but surely not that hard either. And yet no current or planned EV seems to be offering this.

Can someone get onto this please :)

> And yet no current or planned EV seems to be offering this.

In the UK, Ovo customers can do vehicle to grid transfers from their Nissan Leaf, with an appropriate charger.

https://www.ovoenergy.com/electric-cars/vehicle-to-grid-char...

Nice find! This is exactly what I had in mind!

It is curious that this system is only compatible with Nissan leaf though. Perhaps we should work on a standard?

Heating or cooling of buildings is probably easiest way do that in large scale.
I am not sure... where I live (Australia), the electricity supply policy is essentially aimed at avoiding brownouts on hot days, I suppose for the fear of losing building cooling (this has resulted in fatalities in the past). This incidentally results in having a massive amount of standby power generation, and rather high electricity prices.

I think the low hanging fruit (in Australia at least) is various industrial users (eg aluminium smelters). The politics around this are fascinating, but unfortunately too complex to describe properly here...

We are going to need more than just those 3 solutions they mentioned. One of them is demand side management systems, as you mention. These behind the meter (BTM) solutions are going to vary a lot in the scope they address.

You mention using EVs. This will happen in the future, but it is still a ways a way for a few reasons. The primary reasons are because EV adoption is still rather low (adoption is increasing fast and penetration varies by region), and because there is often little monetary incentive, largely because tariffs (electricity rates utilities charge) are not sophisticated. For more sophisticated (and effective) rates to incentivize actions like what you mention, we are going to need more intelligent systems in front of the meter (the transmission and distribution systems that utilities control), and those are often enabled by smart meters (AMI).

For demand side management, think beyond physical batteries. Think virtual. Buildings can act as virtual batteries as they can vary consumption (which is largely enabled by thermal inertia). A lot can be said about energy right now, so I'm not trying to be long-winded...

Also, we're on it! At yize nrg[1], we are lowering HVAC energy costs for large buildings using intelligent agents. We save money by lowering consumption and by doing so at advantageous times, like when prices are higher (based on LMP or tariff). This is demand side management, and we can also offer demand response services back to the utility. [1]: http://www.yizenrg.com

One thing I don't hear discussed much is that we really need enough renewables installed so that on good days for solar and wind, we're actually generating much more than 100% of demand. This then substantially reduces the fraction of the time we depend on expensive storage. This only works though if we have additional variable demand that can kick in when things are going well, both to stabilize the grid and to provide a profitable market for energy. This is where technologies like Prometheus are developing could fit in really well - generating carbon-neutral aviation fuel from atmospheric CO2 and electricity, so we can decarbonize those parts of the economy that cannot switch directly to electric power.
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I think it more likely that utilities (or someone) will begin buying up heating, cooling, and other flexible demand so that they can use a much higher % of their renewables efficiently.
Problem with many of these schemes is that they are capital intensive, so if you can run them only when there's an oversupply of renewables on the grid, well, the economics are going to suck.

I do think that synthetic fuels is a likely solution for things like long distance airplanes which are very hard to decarbonize otherwise.

> electricity generation is the single biggest contributor to climate change—responsible for 25 percent of all greenhouse gas emissions and growing every day

To put it in perspective: livestock clocks in at 18% and transportation at 13%. [1]

But greenhouse gas emissions is not all that counts, there's also acidification, eutrophicatoin (phosphor pollution) and land use. Livestock clock in very high on all these points. [2]

We need land for forest: reduce footprint while re-creating habitats.

Good to know Bill also invests on that side of the picture. [3]

[1] http://www.cowspiracy.com/facts [2] https://phys.org/news/2018-05-reveals-foods-markedly-environ... [3] https://www.cnbc.com/2019/01/21/how-bill-gates-backed-vegan-...

We need a change in culinary habits, eating meat each day for seven days a week isn’t pheasible on the long run. And I don’t think people will flock to eating artificial meat, I don’t think real milk has been replaced by soy milk.

Also, a fact left unsaid by most of the people commenting on this, we need to reverse the engines of economic growth, this planet doesn’t have the resources of providing a middle-class lifestyle for 7 or 8 billion people. In essence, I’m saying that Malthus was right, and the longer we fight against his ideas the longer it will take for us to complain about stuff that I’m afraid is already outside of our control.

I’m not really sure what sort of event will bring the next environmental state of equilibrium, we used to rely on wars and lack of antibiotics for that in centuries past, but I’m sure it won’t be pretty.

I think the effort to get people to stop eating meat and XYZ favorite food isn't going to work. A lot of people eat what they eat because they don't really have much food choice. And with some people pushing weird options like bugs as a protein source while the rich will surely keep eating normal old burgers, life is starting to feel like a bad scifi movie.

I think the absolute biggest and most immediate solution is eating less. Not less beef. Not less pork. Just less of everything.

Obese people can easily consume 2x or more of the food a non-obese person takes in. In America alone, about 1/3 of the country is obese. Doing incredibly rough math here, cutting the calorie consumption of that top 1/3 in half would be the equivalent of 1/6 of food consumption vanishing. As someone from a rural family full of almost-carnivore 400+ pounders, getting them to cut their calories to ~2500 calories a day would be like half the neighborhood and their consumption simply vanishing.

And that's not even factoring in the gas we need to burn to accommodate the greater mass on airplanes, in cars, etc. Dropping the average weight of obese countries by 1/3 would put a big dent in emissions.

People have been prophesizing collapse and mass death for decades. They were wrong every time (obviously).

Do you have the numbers to back up your claim about middle-class lifestyles?

We do currently witness mass death for insects, which had managed to survive through quite a few geological revolutions but which apparently cannot survive the humans’ need for industrialized agriculture (and you cannot feed 8 billion people without industrialized agriculture). And the extinctions among the mammal genre are already pretty well known.
For millennia, actually. They have been right a few times.
> I don’t think real milk has been replaced by soy milk.

It doesn't taste like cow's milk though. And it's not trying to. Artificial meat on the other hand has a goal of being as close to beef as possible.

> this planet doesn’t have the resources of providing a middle-class lifestyle for 7 or 8 billion people.

So what? What do you propose, concretely?

> Malthus was right,

Again, so what?

I'm not the person you're responding to, but I think the only way to fight climate change is by changing to an economy that doesn't rely on increasing production, and accepting a lower standard of living.

I see people blaming climate change on overpopulation, but this isn't really the truth - a majority of the world's energy usage comes from first world countries.

> and accepting a lower standard of living.

I think nearly everybody is ready to accept a lower standard of living... for their neighbourghs!

How much of a reduction are we talking about? Because if it's far enough, then it won't really be any different than the destruction of our civilization. At that point we might as well go full steam ahead into climate change, because the results of it aren't actually set in stone. The IPCC says that we still don't know how to properly model clouds in our climate change models - they could have a significant cooling or warming effect.
> So what? What do you propose, concretely?

I did say:

> I’m afraid is already outside of our control.

so you could say I'm a defeatist, as in I know of no workable and ethical solution. I am just laying out of the facts as I think they are happening.

Maybe we agree in the following conclusion:

Global warming is here to stay (because only a global effort can constrast it and human nature is against global efforts). Let's stop pretending we can make anything about it and let's instead focus on adapting to it (because humanity thrives when everybody can try and improve his own condition without sliding into theft).

Livestock only accounts for so much globally because much of Asia and Africa contributes little to CO2 output other than growing livestock. But that’s rapidly changing as those countries develop. The amount of CO2 China added to its footprint in the last year alone is more than what would be saved if the entire US switched to being vegan. As India and Africa follow the development trajectory of China, livestock will become a very small portion of CO2 footprint, just as it is in developed countries. (In the US, the difference between the average diet and a vegan diet is just a few percent of your footprint.)
>> (In the US, the difference between the average diet and a vegan diet is just a few percent of your footprint.)

I can believe that but could you please source it?

I think this was a commonly misinterpreted study from 2016.

https://dash.harvard.edu/bitstream/handle/1/33797273/BOLAND-...

With this being the key figure: https://postimg.cc/pmQCfdZq

And the key conclusions from that table:

"The impacts from food production for a vegan diet reflect the least GHG emissions when compared with that of a meat-based or vegetarian diet. As per Table 10, vegan diets produce carbon dioxide emissions of 1,798 g/person/day, showing the lowest amount of emissions, versus 7,891 g/person/day from a meat-based diet, demonstrating the highest emissions (Table 10). Vegetarian diets produce slightly higher emissions than a vegan diet, totaling 2,622 g/person/day. The largest individual food group contributor is red meats within the meat-based diet in the amount of 5,153 g/person/day. At the opposite end in a vegan diet, the lowest contributor to GHG emissions is potatoes."

Every study I am aware of is clear that a vegan diet is less carbon intense than a carnivore diet. Beef especially, which is reported as 49% of the total for meat eaters.

I think the people suggesting that "in the US it would raise CO2 emissions" is like a third-order effect people imagined up by drawing a box around the US and saying emissions from cattle grown in other countries for our consumption somehow emit carbon that doesn't get to the US while simultaneously assuming land use conversion in the US to increase agricultural output of plants which would increase emissions locally. Maybe. A lot of our crops go to feed those cattle.

I would be extremely skeptical of any claim like this that flies in the face of 3rd grade science class where we learned that at each step up in the food chain 90% of the energy is lost to support systems like... being alive... while only 10% remains as biomass to eat. This is basically thermodynamics in action with edge effects that contrarians want to focus on.

However the food wastage/carbon footprint from Cereals,vegetables and fruits is far greater than Meat, milk and fish combined.

Pic: https://postimg.cc/D4ZNpBLz

This pic does not say if it's talking about the total or the total per unit consumed, nor does it give a measure of what the total is. The chart is unfortunately not especially helpful in a vacuum. Which is not to say you're interpreting it wrong, I just cannot tell if your conclusion there is actually valid. Or if it's post-consumer (i.e. table scraps) or industrial (i.e. animal feed that goes bad) which dramatically changes the interpretation if animal production and cereal grain waste are correlated.
This doesn't really make sense, though. You have to grow grain in order to raise livestock. Without seeing how these numbers were calculated, it's hard to say exactly what this graph is showing.
I guess it depends on the definition of 'a few percent' in what they said but I think you're misinterpreting it. They don't seem to be saying it wouldn't lower your emissions, they're claiming it's a small part of your emissions.

The change in that paper is ~2 tons/year, and average use in America is ~16 tons/year so about 1/8th. It depends if you think ~12% is 'a few percent' or not.

>It depends if you think ~12% is 'a few percent' or not.

I find that people have no consistency in such matters. What counts as enough of a difference to care about seems to change upon the issue and just so happens to generally align with an individual's view of if an issue is worth worrying about or not.

The definition of "meat-based" in that thesis is interesting:

>> Meat-based diets presume consumption of a combination of plant-based foods in combination with differing kinds of meats and fish and can include milk products, honey, and eggs.

So "meat-based" is any diet that includes any amount of meat. A person who eats a beef steak every day and a person who eats a chicken leg twice a week are both counted under "meat-based" and their environmental impact is calculated as one, and compared to vegan and vegetarian diets'.

I find that dodgy to say the least.

Also, I don't see where the bit you quote agrees with, and so is a likely source for, the bit of the OP's comment I quoted.

I'll re-emphasize the table I linked before, though I agree with one of the other responses that the OP meant that the benefits are marginal on an overall basis so my response wasn't strictly addressing the comment.

https://postimg.cc/pmQCfdZq

They absolutely distinguish between poultry and beef, though they don't distinguish steak from hamburger. They specified exactly what that breakdown was in the table and I doubt that it's random.

137gm red meat, 57gm poultry, 22gm fish per day on average per person using the "meat-based diet" model.

Assuming that pork and beef are both "red meat", the USDA availability chart (couldn't find consumption) is here:

https://www.ers.usda.gov/data-products/chart-gallery/gallery...

and what I see is about 100 pounds of red meat, 65 pounds of poultry, and 15 pounds of fish per person per year available. 100 pounds of red meat per year is 124gm/day, and the ratios are a little off but not by a ton. They definitely report what their diet assumptions were though... my guess is they had a more robust model diet from USDA they used than the chart of clearly not quite the right dataset I took that from.

>> 137gm red meat, 57gm poultry, 22gm fish per day on average per person using the "meat-based diet" model.

There's a big gap between that and a vegetarian or vegan diet. There is definitely a lot of room in between for plant-based diets with a reasonable amount of meat (say chicken or fish twice a weak and a Sunday roast once or twice a month). I'm willing to bet that this kind of diet is much more common than one including a hearty portion of meat every day and that comparing this diet to vegetarian or vegan diets would yield a much less significant difference in terms of environmental impact.

This seems unlikely to have escaped the author? Of course a hybrid diet would be in between, I'm just saying that the diet breakdowns they chose to present are almost certainly model diets from literature rather than arbitrarily chosen to make meat eaters look bad. It's a thesis, not PETA marketing material, there are some standards for rigor and they would have needed to cite and justify why they chose what they chose.

That said, I honestly do not think that your diet suggestion is common for Americans, I rarely see people go a meal without meat. The total of 216gm/day is only 7.6 ounces of meat, and I remember getting weird looks ordering only a 6 ounce steak as an adult. And burgers are frequently about a half pound too. Or a chicken breast. It seems totally believable to me that this is average even accounting for less frequent consumers of meat.

I take efforts to rarely eat it so I'm probably barely different from vegetarian. Obviously hybrid diets will fall somewhere in between? I'm not presently an advocate for no-meat product diets because I don't like extremes but I am an advocate for using substitutes when there's little difference. Like taco bell meat could be soy-based meat-substitute ground and literally no one would notice.

>> This seems unlikely to have escaped the author? Of course a hybrid diet would be in between, I'm just saying that the diet breakdowns they chose to present are almost certainly model diets from literature rather than arbitrarily chosen to make meat eaters look bad. It's a thesis, not PETA marketing material, there are some standards for rigor and they would have needed to cite and justify why they chose what they chose.

Why assume so much? The thesis is in the link you provided. You can easily check whether what you suppose in this comment is true or not.

>> That said, I honestly do not think that your diet suggestion is common for Americans, I rarely see people go a meal without meat.

So this "meat-based" diet is only relevant to Americans? That makes sense- but in that case, the comparison with vegetarian and vegan diets is also only relevant to Americans. i.e. it's American "meat-based" diets that are more environmentally wasteful compared to American "vegetarian" diets etc.

Cowspiracy has been debunked over and over again also it's good to know that bill invest on GMO, at least now we know what this side of the picture is.
Yes. And other shady investments. I wasnt trying to paint him a saint. ;)
You can't really compare CH4 and CO2 emissions. They have completely different lifecycles and short term properties.

Those livestock emissions nearly do not contribute to ocean acidification, and half of it will be gone in 20 years.

Bill Gates: somebody buy my nuclear stuff, I already invested so much
Bill forgot the only thing that can truly be a game changer: Nuclear Fusion. In the long run, this is the only solution that can provide the amount of energy required by our modern society.
> our modern society

You probably mean future society, as this technology is not really viable yet (in its current form).

Citation needed.
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I don't think so, not for the foreseeable future at least - fusion has to be cheaper than fission to be interesting, and fission is probably too expensive at the moment already.
Fusion is also the only energy source which will allow us to reverse the worst effects of climate change (melted ice caps in particular).
Very unlikely that fusion will have any impact on climate change on the timescale which is necessary. The cuts need to be made over the next 20 years, even if we had the technology, it would take a lot longer to scale up.
Not sure why only fusion power would allow that. Solar power is making use of energy that's already heating our planet without us making use of it. Turning solar radiation into electricity instead of heat, makes more efficient use of energy we already have without having to generate more of it from different sources, like fusion.

And the amount of sunlight we receive is enormous. If we could make use of a significant faction of that, it would provide more energy than we ever need. There's no reason that can't do anything that fusion power will ever be able to do on Earth.

The only real advantage fusion power has over solar is that it's independent of the sun and can be used in deep space. Well, once it finally works.

It's pointless to debate whether we should use a technology we don't have yet.
I'm currently reading Griffith's Classical Electrodynamics and Jackson's Electrodynamics, coupled with lecture notes on plasma physics, in order to take a crack at the problem of nuclear fusion. Many other people are doing similar things, because it may possibly be the most important invention that anyone will ever create.
Oh, I don't mean that we should ignore fusion. We should invest in its research, probably as much as is helpful to speed it up. But when considering how to reduce greenhouse emissions right now, fusion is not an option.
Ja, called sun. Already an off-earth installation available. Transfer of energy via radiation. Has just to be collected and transformed to electricity.
Nuclear fusion and fission are both exceptionally complicated ways to boil water, and even if given an ideal water boiler, turbine and cooling plants still need to be built for them and situated somewhere that about 3 times as much heat energy can be released into the local environment. This is known as thermal pollution:

"ultimately, when heat waves are extreme enough, power plants will need to draw down their power output."[1]

Here [2] is a study which shows anthropogenic heat emissions from energy consumption are a pressure on global climate. If we put out another 200%+ of whatever energy we consume, in the form of thermoelectric cooling (heat) then quite surely that will amount to a bigger problem.

Also, "Thermoelectric power use has a significant impact on water resources and the power sector is highly dependent on these water resources; the United States Geological Survey (USGS) estimated on a national level that 41% OF ALL FRESHWATER WITHDRAWALS in the United States in 2005 were for thermoelectric power operations, primarily for cooling needs (Kenny et al 2009)."[3]

I believe the real game changers are plainly solar and wind. These have shown the most rapid improvements from investment. On similar timescale to developing fission or secure nuclear, floating oceanic wind and solar combined with hydrogen generation rigs (and even ocean plastic filtering) are possible...

[1] https://www.sciencedirect.com/topics/earth-and-planetary-sci...

[2] https://link.springer.com/article/10.1007/s10584-017-2092-z

[3] https://iopscience.iop.org/article/10.1088/1748-9326/7/4/045...

> 3 times as much heat energy can be released into the local environment

Or used for desalination, hydrogen, syngas, ammonia, methanol, ethanol production [1] etc.

http://www.world-nuclear.org/information-library/non-power-n...

Also, your estimation is incorrect. The thremal rated power of a nuclear reactor doesn't mean it releases 3x as much heat in the environment. At least 1/3 of the thermal energy is converted to electricity, and part of what remains is fed into a new cycle. The overall efficiency of a nuclear reacor is 33-37%. Gen IV reactor projected efficiencies are above 45%.

Waste heat cant simply be used for this and that, or else we would see all existing thermo-electric powerplants already doing so. Efforts to make thermo-electric plant more efficient and use waste heat are ongoing, but full use of waste heat would be a more game changing development than practical fission reactors !

Its rather rhetorical for us to quibble with my statement "about 3 times.." But in my readings on the matter 33-37% is the theoretic optimal running efficiency of most existing nuclear plants (depends on the kind and expense of turbine cycle and cooling system employed).

Combined heat and power (CHP) is a thing, though mostly in colder climates where there's a need for heating in the winter.

In principle you could do the same with nuclear, but there's challenges in siting a reactor close enough to a big city, and also current reactors tend to be too big. SMR's might help, and there's active research in this area.

SMRs likewise require generators and cooling plant, 2 or 3 times as much cooling as electricity produced, perhaps even more if its to be done most economically. So if CHP is justification for such release of heat into cool environments - they should be categorized as mainly a source of heating, not high value electrical energy. An ability to make continuous heat on this planet is not a futuristic energy supply in its own right, it falls well short of the "game changer" goal.
Thermal nuclear reactors have their MWt rating 3x of their MWe. All of them produce heat.

Generators? Cooling Plant? I don't know about others, but NuScale Power's SMR has natural circulation an passive cooling.

https://www.nuscalepower.com/about-us/faq

That's internal passive cooling which they mention briefly in their faq (transferal of heat from their reactor to their output loop). These units take in water and output steam, and they need attached to thermo-electric plant to produce electricity. They are water boilers.
No, solar is fine. Well, that's also fusion power in a way, but driven by an existing fusion reactor that doesn't cost us any energy. And for the next couple of centuries or millennia, it will continue to produce more energy that we'll ever need.

Nuclear fusion would certainly be nice if it could be made to work, but I've lost my enthusiasm about that a long time ago. Solar is giving us far better returns.

It always interests me that lithium batteries are used in situations with such different constraints: from mobile phones (lightweight, compact, frequent irregular (dis)charging, etc.) to grid storage (controllable (dis)charging patterns, weight and size are less important).

I wonder which other, less battery-oriented, chemical reactions have been investigated for grid storage. For example, non-rechargable aluminium batteries have been suggested for electric cars ( https://en.wikipedia.org/wiki/Aluminium%E2%80%93air_battery ); I could certainly imagine a substation topping up the grid by corroding a huge heap of metal (aluminium is abundant, but heavier materials could be used since they don't need to be mobile).

The interesting dynamic with such non-rechargable "batteries" is how they're manufactured: they would come from surplus production at times of abundant energy. AFAIK energy-intensive processes like aluminium smelting are already used to balance the grid (either directly, with contracts between both parties; or indirectly, by changing energy prices).

Are the round-trip efficiencies of such reactions too low? Are the energy quantities too low? Would this just be an indirect (and hence less efficient) form of the existing load balancing?

The problem is "lithium batteries" is too wide category. There are vastly different chemistries that just happen to have lithium in them that all get grouped into "lithium batteries". All those applications you mention, for most they each have their own dedicated chemistry.

This is a good approachable article that goes over all the common types of lithium batteries. https://batteryuniversity.com/learn/article/types_of_lithium...

What about reducing the consumption of energy?

According to Wikipedia [1] there is a huge difference in consumed kWh per capita in different regions. It seems relatively obvious why EU why are using 5x more energy than Africa, but can someone explain why US is using 2x more than EU? Between 1990 and 2008 US reduced the consumption by 2%, could the cut be larger?

[https://en.wikipedia.org/wiki/World_energy_consumption#Trend...]

Totally off-topic. I like the design of the site so I looked up the source.

There's something like 25 000 lines of JS and CSS o_O.

These solutions are touching only the technical aspects and I believe most experts probably know exactly what to do, but that doesn't mean they can actually do it simply because its execution depends largely on politics.

We can have one country practicing it but another just doing the complete opposite to ruin it for everyone, then realistically we don't really make any progress at all no matter how much effort we put in.

For any climate change solutions to really become effective, it will definitely require a joined global effort. That's where our root problem is, until we can solve that the rest are just useless noises.

Why not biomass? For millions of years the nature balanced CO2 itself with plants, water cycle and fires. Massive reforestation would help with water retention problems, biodiversity etc.

Solar, wind, batteries, nuclear sound big but they are not environmentally neutral (massive and toxic mining of rare materials, noise, poluting production, toxic recycling, disruption of airflow[1]).

Burning fosil fuels is dead-end way but do we want to make this planet a complete artificial wasteland full of solar panel, wind farm, battery and radioactive landfills because "we wanted to stop CO2 emissions at all costs"?

[1] https://www.scientificamerican.com/article/wind-power-found-...

Simply put: biomass is not a good technology. You need huge,huge fields to produce enough crops for turning into biofuels. Those fields need water, space, pesticides, and labor, it's simply not economical compared to solar or wind on the same location.
Massive biomass plantations don't really help biodiversity. The arable land of the earth that isn't already used for growing food or cities is desperately needed for nature.

And as another poster already pointed out, biofuels are horribly poor in terms of energy produced per area. There's simply not enough land on the earth to produce enough biofuel to run our civilization.

For a most egregious example of this, see the ongoing disaster in Indonesia where pristine rainforests are cleared away to make room for palm oil plantations, so us Westerners can feel good about using biofuels. Heartbreaking.

One obvious step that seems to be missing is having governments acknowledge this as a top priority. Make carbon-based energy production expensive enough that these technological innovations are the only alternative.

It seems like a classic case of the Innovator's Dilemma[1]. We are so economically dependent on carbon fuels that the incentives to develop and adopt renewable energies are not yet strong enough. Shouldn't governments do more to speed up that adoption curve?

[1] https://en.wikipedia.org/wiki/The_Innovator%27s_Dilemma

> One obvious step that seems to be missing is having governments acknowledge this as a top priority.

It is missing because it's not possible!

Any government who doesn't have economy at its top priority will be overthrown. Economy can at most be slightly slowed down in order to push green policies, but that's it: anything more, and next government will be voted on the promise to restart coal mines!

I am all for renewable energy but what worries me the most is that our world population in out of control. At what point do we factor this in and start doing something about it? Even with renewable sources of energy can we sustain such growth? I understand nobody wants the government telling them how many kids they can have but I just don't see how we can keep on going this way, and I think a decrease in the population rate would help the climate out as well maybe even more so than renewable energy.
I don’t think it’s the number of people the problem, but rather the demand for resources a few people from the Western world create.
That's not an either-or question. Both population growth and per-human resource demand need to decrease for our society to survive the next 100 years.
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Many predictions of population growth converge to a value between 9 and 12 billion, maybe followed by a slow long-term decline after 2050 or so. This would be high but manageable with proper resource distribution.

These are more pessimistic predictions, of course, but the more optimistic ones are based on the observable trend that higher standards of living correlate with lower birth rates.

The world population will saturate around 10B. It's not really something to worry about for two reasons: (1) From what I've read, there's very little that can be done about it in terms of policy. (2) The largest effect has been caused by the exponential growth in the last couple of centuries. The additional 50% won't bring anything radically different.
Gates has solutions for that too. Lifting people out of poverty by tackling healthcare, nutrition, and education issues, helps improve living standards and is correlated with lower birth rates.

E.g. providing energy to villages that currently don't have any so they can turn on the light at night (education) and pump clean water (health), actually helps achieve this.

The growth of the world population is already slowing down. As someone mentioned, it will probably peak at 10 billion. Many countries already have near zero or even negative growth. Increases in prosperity and education do a lot to limit population growth.
I tend to agree with this (but I admit that I haven't given it much thought). For the most part, population growth is far higher in developing countries. As some of the other commenters here point out, population growth tends to slow down as your country gets richer. However, the issue is that the environmental impact of people in rich countries is far higher per capita.

Some back of the napkin math:

- India population = 1,324,171,354 [0]

- India growth rate = 1.19% [0]

- India CO2 metric tons per capita = 1.58 [1]

Assuming each additional person has the same per capita carbon footprint:

1,324,171,354 * 1.0119 * 1.58 = 2,117,087,809 additional tons CO2/year

Compare to the United States:

- US population = 328,863,150 [2]

- US growth rate = 0.62% [2]

- US CO2 metric tons per capita = 15.53 [1]

328,863,150 * 1.0062 * 15.53 = 5,138,909,636 additional tons CO2/year

So even though the US has 1/4 the population and a lower growth rate, the growth of carbon footprint is 2.5 times higher. These numbers are obviously very inexact, but the point is that if you believe that the current rate of CO2 output is unsustainable (and this is hard to dispute), then even if the world population levels off, this is likely due to increased prosperity. And increased prosperity means more consumption per capita and more consumption means more carbon footprint (and other environmental damage).

[0] https://en.wikipedia.org/wiki/Demographics_of_India

[1] https://www.ucsusa.org/global-warming/science-and-impacts/sc...

[2] https://en.wikipedia.org/wiki/Demography_of_the_United_State...

World population growth is said to be slowing down. But, in regards to what to do about it, support good sex education in schools, and support policies and groups that provide easy and free access to birth control options. The best way to combat overpopulation is to help people prevent unwanted pregnancies. Planned Parenthood.
One fundamental step that we could take tomorrow is ending the subsidies and tax breaks on oil, and reassigning them to renewable energy sources.

Why we haven't done this already: special interests controlling our government.

If anyone can help for climate change - it's easy: don't eat beef. Really. Сattle produce TONS of methane. Less consuming => less market share.
Cows are also among the most inefficient at converting food to ... food, and responsible for a large part of habitat destruction world wide (eg cutting the Amazon for pasture), which is I think an equally serous problem to global warming.
* Weed Plant for Paper/Fuel/Wood

* Nuclear over Coal

* 100% Ethanol over petrol/ethanol mix

* Replace Garbage under ground with Bio gas/Bio fuel recycling centers

* Open Source design/plans/information of all tech in today's world

* Ban on GMO food , instead 100% organic

Its almost like its an SCAM for censorship, control , money and power