Could you please stop posting ideological flamebait to HN? It leads to ideological flamewar, which is just what we're trying to avoid, and you've unfortunately been doing it repeatedly.
Note this isn't a guilt trip about the English and French colonies in North America, though the title might seem to imply that.
The major bloodbaths took place further south with the overthrow and slaughter of the Inca and Aztec empires -- with populations of 12 million and 5 million, respectively.
> It's the UCL group's estimate that 60 million people were living across the Americas at the end of the 15th Century (about 10% of the world's total population), and that this was reduced to just five or six million within a hundred years.
The only thing that was that early, that rapid, and that devastating was the diseases introduced by early European visitors that preceded their colonization by decades and leagues.
It's mostly about the introduction of diseases like Smallpox and Malaria that did almost all of the killing. Lots of places like the American South and the Amazon basin lost huge populations without any European having to show up in person.
Are you implying that several hundred of people (guided by Hernán Cortés) killed 5 million of people?
The New Spain conquest (current Mexico) was done with the help of natives that hated Aztecs. Even with the help of gunpowder it would have been almost impossible to achieve that body count. Thus, the Spanish Crown wanted the help of the Catholic Church, so it promises keep the population to christianize them.
Question, beacause i'm not familiar enough with how trees "suck" co2 out of the air. This study is saying it would take something like 100 forests the size of France to solve the climate change problem by tree growth alone. Would it be possible to genetically modify a tree to consume C02 100x more than a regular tree so we would only need 1 france of mutated trees?
The reason trees pull CO2 out of the atmosphere is that they turn that carbon into, well, the tree. It doesn't just disappear. So consuming 100x more CO2 would result in a tree that's 100x as large.
The Wikipedia article on photosynthetic efficiency[1] is informative.
TL;DR: since extracting carbon from CO2 is energetically unfavorable, it needs to be powered by sunlight. Typical plants are 1-4% efficient in their overall usage of solar energy to generate sugars, and it's not possible to get above ~11% without using some totally different biochemical process.
Some plants are adapted to be more efficient than others, but I think we can be pretty confident that there are no simple tweaks to radically increase efficiency that billions of years of evolution haven't already stumbled on.
What would be really nice to invent is some superior alternative to existing photosynthesis that can better convert sunlight, water, and CO2 into organic matter than existing plants can. Once you've got that it might not matter whether they plants are trees or algae, so long as the organic matter can be buried.
They're looking at GMing Nitrogenase into plants so that they're no longer limted by the lack of Nitrogen, they're also working on copying C4 photosynthesis into C3 photosynthesis plants so they can more efficiently use CO2.
A superior form of photosynthesis isn't easy to imagine, the one we've got seems to use nifty quantum effects to be very efficient, I think about 80%.
Earth cycles carbon, there's been a few spells when it has run out of carbon and turned it a snowball, seemingly saved by carbonate rocks being recycled by volcanoes.
I think there'll run out of phosphate before then though.
Burying it is a waste. Better to grow trees (and bamboo) to make timber, and use it to replace concrete and steel (which are responsible for huge amounts CO2).
"The study also has a bearing on discussions about the creation of a new label to describe humanity's time - and impacts - on Earth. ... the Anthropocene."
I've been hearing about this as if it's a new label for about 15 years now. I was pretty certain we've already accepted this term and generally accept it's a very clear, measurable geologic epoch.
The article says the scientists estimate the CO2 reduction due to population decline as 7 to 10 ppm. Yet they claim this caused the Little Ice Age. That doesn't seem justified; that small a CO2 change doesn't have that much of an impact even on the highest estimates of climate sensitivity (and those highest estimates are known to be too high anyway). For comparison, the CO2 change since the start of the industrial revolution is about 130 ppm.
Agreed. The indigenous peoples were not burning fossil fuels either. This signal is pretty weak. The same could be claimed about the Black Death that ravaged Europe.
> The indigenous peoples were not burning fossil fuels either.
They were changing the use of the land, though. The hypothesis appears to be that the land that had been cultivated reverted back to forest, which meant more trees and hence more CO2 uptake. (Though even that could be questioned, since crops also take up CO2, and growing new crops every year might well take up more CO2 than a forest of trees that just grow once and then stay there.)
Crops get eaten and their straw rots, releasing the CO2 they've sequestered. That happens with trees too, but less completely and over a much larger time scale.
I agree it doesn't seem justified, but keep in mind CO2 effects are logarithmic, so ppm is a poor measure. 10 ppm at 200 ppm is as significant as 20 ppm at 400 ppm.
>The article says the scientists estimate the CO2 reduction due to population decline as 7 to 10 ppm. Yet they claim this caused the Little Ice Age.
Did you read a different article to me? Both the UCL scientists and an unaffiliated scientist said there were also natural processes at play, but the reduction in CO2 had a large impact.
Which doesn't make sense because that small a change in CO2 cannot have a "large impact" given what we know about the sensitivity of the climate to changes in CO2.
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The major bloodbaths took place further south with the overthrow and slaughter of the Inca and Aztec empires -- with populations of 12 million and 5 million, respectively.
> It's the UCL group's estimate that 60 million people were living across the Americas at the end of the 15th Century (about 10% of the world's total population), and that this was reduced to just five or six million within a hundred years.
The only thing that was that early, that rapid, and that devastating was the diseases introduced by early European visitors that preceded their colonization by decades and leagues.
What's your point?
The New Spain conquest (current Mexico) was done with the help of natives that hated Aztecs. Even with the help of gunpowder it would have been almost impossible to achieve that body count. Thus, the Spanish Crown wanted the help of the Catholic Church, so it promises keep the population to christianize them.
TL;DR: since extracting carbon from CO2 is energetically unfavorable, it needs to be powered by sunlight. Typical plants are 1-4% efficient in their overall usage of solar energy to generate sugars, and it's not possible to get above ~11% without using some totally different biochemical process.
Some plants are adapted to be more efficient than others, but I think we can be pretty confident that there are no simple tweaks to radically increase efficiency that billions of years of evolution haven't already stumbled on.
[1]: https://en.wikipedia.org/wiki/Photosynthetic_efficiency
A superior form of photosynthesis isn't easy to imagine, the one we've got seems to use nifty quantum effects to be very efficient, I think about 80%.
Earth cycles carbon, there's been a few spells when it has run out of carbon and turned it a snowball, seemingly saved by carbonate rocks being recycled by volcanoes.
I think there'll run out of phosphate before then though.
https://www.youtube.com/watch?v=2KZb2_vcNTg
https://www.youtube.com/watch?v=JOSCs-yLwno
I've been hearing about this as if it's a new label for about 15 years now. I was pretty certain we've already accepted this term and generally accept it's a very clear, measurable geologic epoch.
They were changing the use of the land, though. The hypothesis appears to be that the land that had been cultivated reverted back to forest, which meant more trees and hence more CO2 uptake. (Though even that could be questioned, since crops also take up CO2, and growing new crops every year might well take up more CO2 than a forest of trees that just grow once and then stay there.)
Did you read a different article to me? Both the UCL scientists and an unaffiliated scientist said there were also natural processes at play, but the reduction in CO2 had a large impact.
Which doesn't make sense because that small a change in CO2 cannot have a "large impact" given what we know about the sensitivity of the climate to changes in CO2.