You're not trying to prevent a budding flame war, you're just trying to preempt the "deniers" from denying.
And I guess you didn't get the memo. You can't call it global warming now. You have to call it climate change. That way, no matter what happens and no matter how cold it gets, evil man and evil capitalism can still be blamed.
Give it a rest. "Climate Change" is a term for any change in climate in any timeframe. The ice age was climate change. Global Warming refers to man made climate change. It's a more specific term.
And I guess you didn't get the memo. You can't call it global warming now. You have to call it climate change. That way, no matter what happens and no matter how cold it gets, evil man and evil capitalism can still be blamed.
If you're trolling, that kind of trolling is not wanted around here.
If you're not trolling, then you didn't understand the article. This study finds a rate of warming at 80% the consensus average of predictions from several years ago, and well within the previous uncertainty bars. So evidence of warming is getting stronger, not weaker, even though the exact predictions of how fast it is warming are coming in on the conservative side of previous estimates.
The dispute has not been about 'warming' in the abstract but about 'catastrophic warming'. So while the evidence for 'warming' may be getting stronger, the evidence for 'catastrophic warming' would seem to be getting weaker.
The longer we go without significant warming, the lower that growth rate will get and the weaker the argument for a catastrophic warming will be.
At current rates of change we are looking in near decades at changing rainfall patterns that will result in regions and countries suffering permanent drought, and others suffering regular flooding and other forms of extreme weather. Among the areas predicted to have severe and permanent drought is the southeastern USA.
Furthermore we are learning about new risks. For instance ocean acidification has put us on a possibly irreversible path towards world-wide mass extinctions of organisms that use calcium carbonate for protection. This includes coral and shellfish. Nobody knows what resulting ecosystem changes will happen, or what the consequences for commercial fisheries which are a critical food supply for populations around the world.
The only way in which these things do not qualify as "catastrophic" is in comparison to worse catastrophes that were within the realm of theoretical possibility, but which now seem less likely. For the planet as a whole, and for people on the planet, the current course bears a series of inevitable catastrophes in our future.
It is all about the feedback. No one disputes the physics of warming created by CO2 emissions. But that warming is insufficient to create the run-away warming predicted in climate models.
The increases necessary to generate the catastrophic scenarios that you (and many others describe) requires that there be an aggregate positive feedback mechanism in the climate system to magnify the CO2 warming (the anthropomorphic warming). If you read any of the literature you'll see this refered to as the 'climate sensitivity'.
No one knows the actual climate sensitivity relative to CO2 concentrations. No one knows what all the various positive and negative feedback mechanisms are. These are all suppositions by climate scientists that are plugged into their models in order to make the models accurate output the historical record. Then there is a grand leap of faith that says that the models will accurate predict the future record. Except that for the last 10-20 years, the models have been wrong. CO2 has increased but the temperature has not changed according to the models prediction.
The original article says:
The Intergovernmental Panel on Climate Change reported in 2007 that the short-term temperature rise would most likely be 1-3C (1.8-5.4F).
But in this new analysis, by only including the temperatures from the last decade, the projected range would be 0.9-2.0C.
So the models will be tweaked (for example by reducing the climate sensitivity) in order to generate output that matches the new historical record which has 10-20 years of no statistically significant warming.
The problem with all this is that the models can always be tweaked to match the historical record while at the same time generating whatever future prediction you want. And if that doesn't work, you just tweak the model again.
I'll start to believe that the models are reasonable when they remain unchanged for several decades while still tracking the actual observations.
First of all a note. I've made a substantial fraction of my living over the last decade from my understanding of statistics. When I look at a projected statistical range of 1.0-3.0 that later got refined to 0.9-2.0 I see that as a fit. Sure, the bottom end of the new range moved out of the bottom end of the old range. But if you watch an A/B test run, you'll see that this is entirely expected. But the median prediction of the new range - the most likely outcome - is 1.55 which is (assuming that the original range was a 95% confidence interval) is inside of 1 standard deviation of the prediction.
Secondly when you say that the warming is insufficient to create the run-away warming predicted in climate models you're in disagreement with the vast majority of people who have actually tried to run the numbers. Having just seen you draw an incorrect "not a fit to the statistics" from something that I know very well looks exactly in line with what I'd expect a fit to look like, I'm going to trust that scientists understand their own numbers better than you understand them.
Thirdly your claim that the new historical record has 10-20 years of no statistically significant warming is just plain false. The article this discussion started about finds that if you just use data from the last decade and project that forward you get an average projection of increasing 1.55C in a period that previous models had said would increase 1-3C. That doesn't look to me like you're not warming.
And finally I'm glad that scientists don't let their models sit still for decades. It is a fact that the models have huge error bars. I want them to improve the models, to bring them down. And the fact that the new models are in good statistical agreement with the old is confirmation that the old models were reasonable (if less accurate than desired). Until we see a statistical lack of fit between old and new data (which has yet to happen) - there is no statistical reason to doubt the science.
In the meantime I'm concerned that the 10 years with the least arctic ice in the summer all happened in the last 10 years. You may dismiss that data point. But in all of the discussions about newly available oil drilling locations and transport routes, it is worth noting that it is a very visible sign of a major global phenomena.
> Secondly when you say that the warming is insufficient to create the run-away warming predicted in climate models you're in disagreement with the vast majority of people who have actually tried to run the numbers.
I think we are talking about two different things here. The ranges you mentioned (1.0 - 3.0) and (0.9 - 2.0) are predictions for the net change in temperature over 100 years when all mechanisms are factored in.
When I said the 'warming is insufficient' I'm talking only about one factor, the greenhouse effect caused by atmospheric CO2. This one factor has been the focus of most of the policy discussions related to global warming since it is the one most closely associated with human activities.
The CO2 greenhouse effect is a single factor that contributes to the ranges you described and by itself is insufficient to create the catastrophic warming represented by the upper end of those ranges or even the mild warming represented by the lower end of those ranges. All the models presume some sort of positive feedback that adds to the warming created by the CO2.
I'm not going to dispute your statement that the new error bars overlap with the old ones but the catostrophic scenarios are obviously associated more with one particular end of the error bars so that the shift in the error bars, while not invalidating the model in their entirety, suggest that the most severe scenarios are less and less likely and it is exactly those scenarios and the policy recommendations associated with them that has been most in dispute.
> The article this discussion started about finds that if you just use data from the last decade and project that forward you get an average projection of increasing 1.55C in a period that previous models had said would increase 1-3C
No, for some definitions of "the last decade" the trend line is cooling and for others it really is flat.
If you define "the last decade" as the ten year period ending this month, the temperature trend looks like this (slight cooling):
(The "woodfortrees index" shown is built from an average of several standard temperature series - if you like HADCRU or GISS or some other specific one you can select it from the popup menu and hit the "plot" button to see that instead.)
The 20-year trend is still positive, but the recent flattening is real and it has already been flat enough long enough that it's starting to pose a serious problem for the model predictions, hence articles like this one.
> But the median prediction of the new range - the most likely outcome - is 1.55 which is (assuming that the original range was a 95% confidence interval) is inside of 1 standard deviation of the prediction.
Er, no. You're assuming the probability distribution is a normal distribution with the median in the middle - it isn't. IIRC, some of the newer attribution-based papers that have been forcing them to shift the window to the left have a positive skew - the median peak is way on the left side and then there's a "long tail" on the right. So depending on which papers they use it's actually possible the new median could be outside the 95% confidence interval of the old range.
But more fundamentally, the natural variation over a decade is +- 0.2 C. If the warming trend for a century is 2 C, then the warming trend per decade is also 0.2 C. Thus a flat decade is readily explainable by normal variation. If the warming trend is instead 1.5 C per century, then a 15 year stall becomes even more reasonable than a decade had been under a faster rise.
The golden question then becomes how this study found a 0.15 C rise in temperature from data over the last decade. I have not read the study. But I know that correctly modeling these things is far more complex than just looking at a long-term average. And given that I know that detailed attempts to produce actual heat budgets for where energy is going have consistently found that the planet has been steadily absorbing large amounts of heat in recent years, I'm inclined to believe their figures over an argument from a temporary stall in global atmospheric temperature.
> The golden question then becomes how this study found a 0.15 C rise in temperature from data over the last decade.
In my skimming of the original article I didn't see where that claim was presented. But if I had to guess, there are at least three ways somebody could accidentally reach that wrong conclusion.
(1) Using something like the woodfortrees link, specify a "From date" year but don't specify an "end date", so you plot, say, from 2002 to "today". The leftmost point on your plot is in January; the rightmost point is in the middle of summer because that's when it is now. Boom, you've got some instant extra warming, assuming you picked a temperature trend influenced by surface thermometer readings.
(2) Instead of looking at actual temperatures, look at a heavily smoothed moving average of temperatures. Or average every decade into a single point and then compare those points. This gives you a plausible excuse to ignore much of the most recent data and the most recent trend ("Tamino" aka Grant Foster often pulls this trick on the readers of his blog Open Mind.)
(3) Instead of looking at the most recent data, google up an old study that ended in, say, 2000 and interpret all talk about "the last decade" as referring to the last ten years shown in that study. :-)
UPDATE: I just thought of another:
(4) Timing. The annual temperature trend is pretty noisy, so over any given ten-year period it might increase or decrease. If you're a "warmist", your favored information sources are going to publish new studies and trumpet their findings whenever the most recent decade now seems to show a big jump compared to the trend it seemed to show in prior years, with headlines like "it's worse than we thought!". So any time this issue comes up, those are the studies/stats that you'll remember and cite.
(the original Mac/PC debates had exactly this dynamic - both Mac fanboys and PC fanboys were generally convinced that their platform was better in all the ways that mattered; their certainty was almost entirely a matter of salience bias and the timing of news release events.)
Why do you think the growth rate will get lower? If we do not have a change in our carbon footprints, it will not get lower, and there will be a catastrophe. Perhaps the catastrophe will be several years after predicted, but it will come.
I was just stating a mathematical fact. If you observe an increase in temperature over a 100 year time period but the last 20 years of that period there is no significant change then the 100 year average will continue to drop if the temperature continues to remain steady.
Note, I just picked 100 to illustrate the math. I'm not sure exactly what number would be right there but the point is that the slope of the line continues to drop as long as the there is no change in the observed value that you are measuring.
You sound angry. Relax. Take a deep breath. Maybe go outside and enjoy the nice late-May weather. Hell, it may not be a bad idea to fire up the grill, even, and make yourself a nice hamburger or hot dog. I promise you will feel better afterward.
1) I agree with you that the parent comment is not preempting anything, it's just a political jab.
2) You're simply wrong that the name change to "climate change" was a leftist thing. Luntz is a chief political strategist for the right wing in America:
The phrase "global warming" should be abandoned in favour of "climate change", Mr Luntz says, and the party should describe its policies as "conservationist" instead of "environmentalist", because "most people" think environmentalists are "extremists" who indulge in "some pretty bizarre behaviour... that turns off many voters".
You're using two terms which are propositions (that is, they can be either true or false), and demonizing them as if they're subjectively defined and able to be manipulated for individual or group gains. That's simply not the case.
Global warming is the fact that the global temperature of Earth has been rising since the 19th century. It either has been warming, or it has not been warming. By fact, it has.
Climate Change is a statical fact. If the Earth is in a state of Climate Change, then there is a significant change in the statistical distribution of weather patterns over a given time period. Whether or not the change is hot or cold is irrelevant, as both cases are alarming.
It's called Climate Change now because it's better defined, characteristic, and accurate than the rather obvious and uninformative term 'global warming.' The planet is not just warming, it's warming at a rate that is statistically significant. If that warming slows, but still stays above a significant rate, then we're still in a state of Climate Change and should still be alarmed.
Now, if you want to have a conversation about the validity of Climate Change with integrity, you would need to focus around the merit of the statistical thresholds defined. It could be the case that the thresholds in which leading climatologists have set are too low to merit being alarmed about. Make that case if you can. Otherwise, there's really no basis to make an argument against it.
If nerds experience a dissidence between their own judgements and reality, we tend to distort reality to conform to our worldview rather than the other way around.
That's why we tend to get hard when we are presented with studies that are cherry picked to cater to our demographics values.
You may "get hard" over confirmation bias, but a lot of us "nerds" are scientifically trained and actually do a pretty good job of interpreting reality. Sure, no-one is perfect, but "nerds" tend to be better than other "demographics".
The thing that really put climate change in perspective for me was when a professor pointed out that the last ice age was just 4-5C colder than today, but that meant that the place where we were sitting, on the shore of Lake Michigan in Chicago, was under a mile of ice.
That seems like a (probably inadvertently) awful example. Chicago is right smack in the middle of the 'tongue' of the Laurentide ice sheet that sticks out way to the south - even today, without miles of ice the climate of NYC and Barcelona are quite unalike while being at the same latitude. At the point of maximum extent global mean temperatures were already rising, there were great big gobs of the Pleistocene in which they were far lower.
'Mean surface temperature' is something that can be directly measured or estimated from paleometeorologic proxies but without models for the underlying mechanisms, it's pretty uninformative.
And the linked references give some idea of how very misleading, taken at face value, mean global temperatures can be.
Even just doing a bit of napkin physics - if one applied the energy needed to heat the top meter of ocean by one degree to the first meter of air, it would be like taking a blowtorch to the layer of air in question.
Examples like that are pithy but they're almost like walking up to a denialist and saying 'I want you to hit me in the face, as hard as you can'.
The point is that a relatively small change to the average can mean major changes locally. It's irrelevant what the ice coverage in New York was. We weren't in New York.
The 'change to the average' is not small. Local changes exceed that all the time, though. I never mentioned the ice coverage of New York.
It's an ass of an example. It's not like I'm calling you an ass for using it but come on. It might have convinced you but it's bad. Many people with a secondary education have airplane lift taught to them in terms of the Bernoulli principle, even if, at the end of the day, it doesn't actually explain lift.
this is a big problem when you judge the climate of whole earth by just one number. "Mean surface temperature" it is called. Even in present article, the author clearly talks about this number being not as increasing as expected, but cautioned the increased uncertainty.
Which means, local variations will increase and that should increase worry not decrease.
In still other words: it doesn't matter what's causing it, we're fucked if the average temperature in the breadbasket of the U.S. becomes similar to that of Texas, as is projected. The question isn't: did we cause it, the question is: can we slow it down?
The projections are at least partly or mostly based on the trends, which means that even if scientists are wrong about the cause, the projections are probably still right. So I think we're fucked either way. Some place more than others. Me, I'm planning on holing up in Oregon with the in-laws to prepare to defend the state's water resources from invading Californians.
Ya, if anything we might be less fucked if it's human caused. Because that way we have some hope (however small) of reducing our carbon emissions. If it's something else out of our control then we could be well and truly fucked. Unless it just suddenly stops happening. Stay tuned!
either way, adapt or die - I don't know that we can do enough to change the climate, or even if we should attempt it, and make the cure worse than the projections.
There is a form of argument which is essentially to take all incoming facts, pattern match them against your existing beliefs, then spit out a matching statement with no evidence of comprehension. This is very common in certain subjects, including politics.
This form of argument is not wanted here. Please do not engage in it.
If you read the article with comprehension you'd find that global warming is happening as predicted, but on the conservative side of those predictions.
Go out and investigate for yourself. You'll find that the error bars on those predictions remain large. Though smaller than they were. And the conclusion that it is human-caused has only become better supported with time.
> There is a form of argument which is essentially to take all incoming facts, pattern match them against your existing beliefs, then spit out a matching statement with no evidence of comprehension. This is very common in certain subjects, including politics.
This is very true on both sides of this argument though.
This is very true on both sides of any argument about anything that people attach tribal identity to. Which includes politics, religion, sports, choice of editor, one true indent style...
Knowing this I try to apply increased scrutiny on arguments from people that I fundamentally agree with, because I know that if I don't do it consciously, then I'll just nod in blind stupidity. I won't claim that I do a good job at it. But I will say that the willingness to take the effort has resulted in my changing opinions on a number of topics over the years.
But, in this case, taking an article that says, "We found warming at 80% of previous average prediction, but well within previous predictions" and concluding that climate science is all bunk clearly indicates a lack of comprehension for what the article actually said.
or we've been lucky so far with the predictions, or been able to fit our predictions to match the data. This is just PREDICTIONS. it's not settled science - meteorologists have been able to stretch their predictions out to a couple of days, but the system is too chaotic for long-term predictions. It's not all bunk, but it's not a perfectly accurate 'science', either, and concluding that it's not indicates a lack of comprehension of the difference between theory and settled fact.
Now, I'm not saying we should foul our nest, just that we don't know exactly what is going to happen, given our current understanding of long-term climate change.
The old "weather is chaotic so we don't understand climate" argument. Thereby letting you dismiss what scientists agree on without even looking at their evidence.
If you know the science, then you'll understand that predicting exactly what the weather will be on one particular day in one month is fundamentally impossible. But predicting what it is likely to average out to in June in Los Angeles over the next decade is both possible, and routinely done (albeit with significant error bars). There is absolutely no contradiction between these two facts.
Let me illustrate with a good example showing how scientists can understand both the predictability of climate and the unpredictability of weather at the same time. I will illustrate with an important example that is not widely understood by the lay public.
If you know what the Hadley cells are, you can predict at what approximate latitude we'll have jet streams, and why. (Google that term if you don't know what a Hadley cell is - they aren't that complex.) You'll also be able to predict that the jet streams will cause weather to follow them, resulting in (for instance) a general west to east flow of weather over much of the USA and Canada. The fun part is that if you know more fluid mechanics, you can also show that the exact location of the jet stream is chaotic. There will be bends and kinks of with a predictable wavelength (about 2x the width of North America if you are interested) and a generally predictable amplitude, but entirely unpredictable location. Those bends will cause warm weather to be pulled north in one place, and south in another. (Therefore when the East Coast is unseasonably cold, the West Coast tends to be unseasonably warm, and vice versa.) But you can't predict WHERE those bends will actually be.
So this tells us a lot about climate (for instance where it will be wet, where you have rain shadows, etc). It tells us a lot about causes of significant variation, including how big the variation tends to be. But it also says that we can know nothing about which way the variation will go in New York City next October.
Your argument boils down to, "You can't even tell me what New York City will be like next October, you obviously aren't doing science here!" Which is simply ridiculous, since in fact the mechanics, average, and average variation are all understood along with the reasons why we cannot get more exact answers!
Everything that I am describing is standard and has been known for decades. In fact I learned it from my fluid mechanics text over 20 years ago.
Please stop using the, "We can't predict the weather so this can't be settled science" fallacy. It is a cheap cop-out to avoid listening to what actually is known by smart people who have devoted their lives to studying the subject.
(Oh, and you learned something kind of fun. The next time you look on a weather map and see the jet stream, you'll know why it isn't running straight across. And just watch - if you pay attention over the next few months you'll notice unseasonable weather on one coast of North America that is the opposite direction of unseasonable weather on the other. And on the weather maps you'll see the jet stream, and know why it happened.)
It's not a fallacy or a cheap cop out. You're of the opinion that what we know about the weather now is all that we need to know, but it's not.
How does the orbit of the moon affect weather? What about changes in the magnetic currents in the Earth's core? Earthquakes? Solar winds? Can you tell me what solar activity will be like in 10 years?
"Everything that I am describing is standard and has been known for decades." How many times have we heard this, just before big leaps in understanding have occurred? Several times, just in my lifetime. It's hubris to believe we know that much about the weather.
I never said that we know everything that we need to. I've repeatedly pointed out that our models have big error bars on them, and there are long lists of things that we need to improve, of which your list doesn't even hit on the most important parts. But the fact that we have significant unknowns doesn't mean that we can't put order of magnitude estimates on our uncertainty, plug those into models, and come up with error bars. In fact that is how those models are developed, and how we develop error bars.
"Everything that I am describing is standard and has been known for decades." How many times have we heard this, just before big leaps in understanding have occurred? It's hubris to believe we know that much about the weather.
I said that after getting through a description of how the jet stream works, and was clearly referring to that description. I did not say - nor did I imply - that the jet stream is everything to do with the weather or climate. Important? Yes. Everything? No.
It is certain that there will be major discoveries over the next 20 years about how climate works. Why is Greenland showing far more melting than expected? How does soot from China affect everything from arctic ice to rainfall in the USA, and how does that affect climate? How much methane will be released as permafrost melts, and what will the climate impact of that be? These are all areas of active research.
But I'd be shocked if scientists 20 years from now disagree with scientists from 20 years ago about how the jet stream works.
Wow, speaking of comprehension - the last sentence that you quoted emphasizes that I was talking about the weather, in general, not the jet stream. And order of magnitude estimates are about as accurate as a neophyte programmers time estimates.
"Chaotic" doesn't mean what you think it means. E.g. There are a lot of things in aerodynamics that are chaotic (especially turbulent flows), yet we can make large scale predictions of how, say, a supersonic wing will behave just fine.
Right, we don't fully understand it. Our models have large error margins, and while they all agree on the trend, the specifics are relatively vague. More research is needed.
What we do understand, on the other hand, tells us we should be extremely conservative when it comes to the environment, and avoid pumping it full of greenhouse gasses, because having the planet heat up may lead to really bad things happening.
I don't get this "We don't understand what's going on, therefore we can keep making a mess" argument that so many people seem to be making.
These two sentences summarize the article pretty well: "The authors calculate that over the coming decades global average temperatures will warm about 20% more slowly than expected. But when it comes to the longer term picture, the authors say their work is consistent with previous estimates."
The problem is that evidence has come out, been confirmed, etc multiple times. Evidence is clear that if we want to avoid the consequences we need to act. However we can't act, in significant part because a large portion of the population is unwilling to believe that the consequences exist.
Not sure what they wanted to achieve with this article, as the article paints a picture different from the title.
1. Likelihood in long term remains the same.
(title betrays its readers)
2. In medium term likelihood of most extreme scenarios is less than what was expected.
(hey ho, extreme scenarios are not to account for, thats why they are extreme)
3. people should be exactly as concerned as before about what climate change is doing
ANyway, the whole news-article is based on one publication. Meh. I would rather ignore the details of one publication because minor difference in details dont matter. The broad picture remains the same.
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"Is there any succour in these findings for climate sceptics who say the slowdown over the past 14 years means the global warming is not real?
"None. No comfort whatsoever," he said.
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So global warming is still real and it is still happening. It is just that the rate of warming has slowed down somewhat.
And I guess you didn't get the memo. You can't call it global warming now. You have to call it climate change. That way, no matter what happens and no matter how cold it gets, evil man and evil capitalism can still be blamed.
If you're trolling, that kind of trolling is not wanted around here.
If you're not trolling, then you didn't understand the article. This study finds a rate of warming at 80% the consensus average of predictions from several years ago, and well within the previous uncertainty bars. So evidence of warming is getting stronger, not weaker, even though the exact predictions of how fast it is warming are coming in on the conservative side of previous estimates.
Not only did he not understand the article, he doesn't understand any part of climate science.
The longer we go without significant warming, the lower that growth rate will get and the weaker the argument for a catastrophic warming will be.
At current rates of change we are looking in near decades at changing rainfall patterns that will result in regions and countries suffering permanent drought, and others suffering regular flooding and other forms of extreme weather. Among the areas predicted to have severe and permanent drought is the southeastern USA.
Furthermore we are learning about new risks. For instance ocean acidification has put us on a possibly irreversible path towards world-wide mass extinctions of organisms that use calcium carbonate for protection. This includes coral and shellfish. Nobody knows what resulting ecosystem changes will happen, or what the consequences for commercial fisheries which are a critical food supply for populations around the world.
The only way in which these things do not qualify as "catastrophic" is in comparison to worse catastrophes that were within the realm of theoretical possibility, but which now seem less likely. For the planet as a whole, and for people on the planet, the current course bears a series of inevitable catastrophes in our future.
The increases necessary to generate the catastrophic scenarios that you (and many others describe) requires that there be an aggregate positive feedback mechanism in the climate system to magnify the CO2 warming (the anthropomorphic warming). If you read any of the literature you'll see this refered to as the 'climate sensitivity'.
No one knows the actual climate sensitivity relative to CO2 concentrations. No one knows what all the various positive and negative feedback mechanisms are. These are all suppositions by climate scientists that are plugged into their models in order to make the models accurate output the historical record. Then there is a grand leap of faith that says that the models will accurate predict the future record. Except that for the last 10-20 years, the models have been wrong. CO2 has increased but the temperature has not changed according to the models prediction.
The original article says:
The Intergovernmental Panel on Climate Change reported in 2007 that the short-term temperature rise would most likely be 1-3C (1.8-5.4F).
But in this new analysis, by only including the temperatures from the last decade, the projected range would be 0.9-2.0C.
So the models will be tweaked (for example by reducing the climate sensitivity) in order to generate output that matches the new historical record which has 10-20 years of no statistically significant warming.
The problem with all this is that the models can always be tweaked to match the historical record while at the same time generating whatever future prediction you want. And if that doesn't work, you just tweak the model again.
I'll start to believe that the models are reasonable when they remain unchanged for several decades while still tracking the actual observations.
Secondly when you say that the warming is insufficient to create the run-away warming predicted in climate models you're in disagreement with the vast majority of people who have actually tried to run the numbers. Having just seen you draw an incorrect "not a fit to the statistics" from something that I know very well looks exactly in line with what I'd expect a fit to look like, I'm going to trust that scientists understand their own numbers better than you understand them.
Thirdly your claim that the new historical record has 10-20 years of no statistically significant warming is just plain false. The article this discussion started about finds that if you just use data from the last decade and project that forward you get an average projection of increasing 1.55C in a period that previous models had said would increase 1-3C. That doesn't look to me like you're not warming.
And finally I'm glad that scientists don't let their models sit still for decades. It is a fact that the models have huge error bars. I want them to improve the models, to bring them down. And the fact that the new models are in good statistical agreement with the old is confirmation that the old models were reasonable (if less accurate than desired). Until we see a statistical lack of fit between old and new data (which has yet to happen) - there is no statistical reason to doubt the science.
In the meantime I'm concerned that the 10 years with the least arctic ice in the summer all happened in the last 10 years. You may dismiss that data point. But in all of the discussions about newly available oil drilling locations and transport routes, it is worth noting that it is a very visible sign of a major global phenomena.
BTW if you want to dig farther, I recommend http://onlinelibrary.wiley.com/doi/10.1029/2011GL048794/abst... for a detailed energy budget of where heat appears to be going right now.
I think we are talking about two different things here. The ranges you mentioned (1.0 - 3.0) and (0.9 - 2.0) are predictions for the net change in temperature over 100 years when all mechanisms are factored in.
When I said the 'warming is insufficient' I'm talking only about one factor, the greenhouse effect caused by atmospheric CO2. This one factor has been the focus of most of the policy discussions related to global warming since it is the one most closely associated with human activities.
The CO2 greenhouse effect is a single factor that contributes to the ranges you described and by itself is insufficient to create the catastrophic warming represented by the upper end of those ranges or even the mild warming represented by the lower end of those ranges. All the models presume some sort of positive feedback that adds to the warming created by the CO2.
I'm not going to dispute your statement that the new error bars overlap with the old ones but the catostrophic scenarios are obviously associated more with one particular end of the error bars so that the shift in the error bars, while not invalidating the model in their entirety, suggest that the most severe scenarios are less and less likely and it is exactly those scenarios and the policy recommendations associated with them that has been most in dispute.
No, for some definitions of "the last decade" the trend line is cooling and for others it really is flat.
If you define "the last decade" as the ten year period ending this month, the temperature trend looks like this (slight cooling):
http://www.woodfortrees.org/plot/wti/last:120/plot/wti/last:...
(The "woodfortrees index" shown is built from an average of several standard temperature series - if you like HADCRU or GISS or some other specific one you can select it from the popup menu and hit the "plot" button to see that instead.)
The 15-year trend is rising, but just barely so: http://www.woodfortrees.org/plot/wti/last:180/plot/wti/last:...
The 20-year trend is still positive, but the recent flattening is real and it has already been flat enough long enough that it's starting to pose a serious problem for the model predictions, hence articles like this one.
> But the median prediction of the new range - the most likely outcome - is 1.55 which is (assuming that the original range was a 95% confidence interval) is inside of 1 standard deviation of the prediction.
Er, no. You're assuming the probability distribution is a normal distribution with the median in the middle - it isn't. IIRC, some of the newer attribution-based papers that have been forcing them to shift the window to the left have a positive skew - the median peak is way on the left side and then there's a "long tail" on the right. So depending on which papers they use it's actually possible the new median could be outside the 95% confidence interval of the old range.
But more fundamentally, the natural variation over a decade is +- 0.2 C. If the warming trend for a century is 2 C, then the warming trend per decade is also 0.2 C. Thus a flat decade is readily explainable by normal variation. If the warming trend is instead 1.5 C per century, then a 15 year stall becomes even more reasonable than a decade had been under a faster rise.
The golden question then becomes how this study found a 0.15 C rise in temperature from data over the last decade. I have not read the study. But I know that correctly modeling these things is far more complex than just looking at a long-term average. And given that I know that detailed attempts to produce actual heat budgets for where energy is going have consistently found that the planet has been steadily absorbing large amounts of heat in recent years, I'm inclined to believe their figures over an argument from a temporary stall in global atmospheric temperature.
In my skimming of the original article I didn't see where that claim was presented. But if I had to guess, there are at least three ways somebody could accidentally reach that wrong conclusion.
(1) Using something like the woodfortrees link, specify a "From date" year but don't specify an "end date", so you plot, say, from 2002 to "today". The leftmost point on your plot is in January; the rightmost point is in the middle of summer because that's when it is now. Boom, you've got some instant extra warming, assuming you picked a temperature trend influenced by surface thermometer readings.
(2) Instead of looking at actual temperatures, look at a heavily smoothed moving average of temperatures. Or average every decade into a single point and then compare those points. This gives you a plausible excuse to ignore much of the most recent data and the most recent trend ("Tamino" aka Grant Foster often pulls this trick on the readers of his blog Open Mind.)
(3) Instead of looking at the most recent data, google up an old study that ended in, say, 2000 and interpret all talk about "the last decade" as referring to the last ten years shown in that study. :-)
UPDATE: I just thought of another:
(4) Timing. The annual temperature trend is pretty noisy, so over any given ten-year period it might increase or decrease. If you're a "warmist", your favored information sources are going to publish new studies and trumpet their findings whenever the most recent decade now seems to show a big jump compared to the trend it seemed to show in prior years, with headlines like "it's worse than we thought!". So any time this issue comes up, those are the studies/stats that you'll remember and cite.
(the original Mac/PC debates had exactly this dynamic - both Mac fanboys and PC fanboys were generally convinced that their platform was better in all the ways that mattered; their certainty was almost entirely a matter of salience bias and the timing of news release events.)
Note, I just picked 100 to illustrate the math. I'm not sure exactly what number would be right there but the point is that the slope of the line continues to drop as long as the there is no change in the observed value that you are measuring.
2) You're simply wrong that the name change to "climate change" was a leftist thing. Luntz is a chief political strategist for the right wing in America:
The phrase "global warming" should be abandoned in favour of "climate change", Mr Luntz says, and the party should describe its policies as "conservationist" instead of "environmentalist", because "most people" think environmentalists are "extremists" who indulge in "some pretty bizarre behaviour... that turns off many voters".
http://www.guardian.co.uk/environment/2003/mar/04/usnews.cli...
Global warming is the fact that the global temperature of Earth has been rising since the 19th century. It either has been warming, or it has not been warming. By fact, it has.
Climate Change is a statical fact. If the Earth is in a state of Climate Change, then there is a significant change in the statistical distribution of weather patterns over a given time period. Whether or not the change is hot or cold is irrelevant, as both cases are alarming.
It's called Climate Change now because it's better defined, characteristic, and accurate than the rather obvious and uninformative term 'global warming.' The planet is not just warming, it's warming at a rate that is statistically significant. If that warming slows, but still stays above a significant rate, then we're still in a state of Climate Change and should still be alarmed.
Now, if you want to have a conversation about the validity of Climate Change with integrity, you would need to focus around the merit of the statistical thresholds defined. It could be the case that the thresholds in which leading climatologists have set are too low to merit being alarmed about. Make that case if you can. Otherwise, there's really no basis to make an argument against it.
'Mean surface temperature' is something that can be directly measured or estimated from paleometeorologic proxies but without models for the underlying mechanisms, it's pretty uninformative.
http://en.wikipedia.org/wiki/File:WhereIsTheHeatOfGlobalWarm...
And the linked references give some idea of how very misleading, taken at face value, mean global temperatures can be.
Even just doing a bit of napkin physics - if one applied the energy needed to heat the top meter of ocean by one degree to the first meter of air, it would be like taking a blowtorch to the layer of air in question.
Examples like that are pithy but they're almost like walking up to a denialist and saying 'I want you to hit me in the face, as hard as you can'.
It's an ass of an example. It's not like I'm calling you an ass for using it but come on. It might have convinced you but it's bad. Many people with a secondary education have airplane lift taught to them in terms of the Bernoulli principle, even if, at the end of the day, it doesn't actually explain lift.
Which means, local variations will increase and that should increase worry not decrease.
we can make short range predictions, but still don't know all of the variables that are controlling the climate.
If mankind is not causing it, then we don't know what's going on and our predictions about the long term (next 100 years) trend are likely wrong.
Oregon does seem like a pretty good plan.
This form of argument is not wanted here. Please do not engage in it.
If you read the article with comprehension you'd find that global warming is happening as predicted, but on the conservative side of those predictions.
Go out and investigate for yourself. You'll find that the error bars on those predictions remain large. Though smaller than they were. And the conclusion that it is human-caused has only become better supported with time.
This is very true on both sides of this argument though.
Knowing this I try to apply increased scrutiny on arguments from people that I fundamentally agree with, because I know that if I don't do it consciously, then I'll just nod in blind stupidity. I won't claim that I do a good job at it. But I will say that the willingness to take the effort has resulted in my changing opinions on a number of topics over the years.
But, in this case, taking an article that says, "We found warming at 80% of previous average prediction, but well within previous predictions" and concluding that climate science is all bunk clearly indicates a lack of comprehension for what the article actually said.
Now, I'm not saying we should foul our nest, just that we don't know exactly what is going to happen, given our current understanding of long-term climate change.
If you know the science, then you'll understand that predicting exactly what the weather will be on one particular day in one month is fundamentally impossible. But predicting what it is likely to average out to in June in Los Angeles over the next decade is both possible, and routinely done (albeit with significant error bars). There is absolutely no contradiction between these two facts.
Let me illustrate with a good example showing how scientists can understand both the predictability of climate and the unpredictability of weather at the same time. I will illustrate with an important example that is not widely understood by the lay public.
If you know what the Hadley cells are, you can predict at what approximate latitude we'll have jet streams, and why. (Google that term if you don't know what a Hadley cell is - they aren't that complex.) You'll also be able to predict that the jet streams will cause weather to follow them, resulting in (for instance) a general west to east flow of weather over much of the USA and Canada. The fun part is that if you know more fluid mechanics, you can also show that the exact location of the jet stream is chaotic. There will be bends and kinks of with a predictable wavelength (about 2x the width of North America if you are interested) and a generally predictable amplitude, but entirely unpredictable location. Those bends will cause warm weather to be pulled north in one place, and south in another. (Therefore when the East Coast is unseasonably cold, the West Coast tends to be unseasonably warm, and vice versa.) But you can't predict WHERE those bends will actually be.
So this tells us a lot about climate (for instance where it will be wet, where you have rain shadows, etc). It tells us a lot about causes of significant variation, including how big the variation tends to be. But it also says that we can know nothing about which way the variation will go in New York City next October.
Your argument boils down to, "You can't even tell me what New York City will be like next October, you obviously aren't doing science here!" Which is simply ridiculous, since in fact the mechanics, average, and average variation are all understood along with the reasons why we cannot get more exact answers!
Everything that I am describing is standard and has been known for decades. In fact I learned it from my fluid mechanics text over 20 years ago.
Please stop using the, "We can't predict the weather so this can't be settled science" fallacy. It is a cheap cop-out to avoid listening to what actually is known by smart people who have devoted their lives to studying the subject.
(Oh, and you learned something kind of fun. The next time you look on a weather map and see the jet stream, you'll know why it isn't running straight across. And just watch - if you pay attention over the next few months you'll notice unseasonable weather on one coast of North America that is the opposite direction of unseasonable weather on the other. And on the weather maps you'll see the jet stream, and know why it happened.)
How does the orbit of the moon affect weather? What about changes in the magnetic currents in the Earth's core? Earthquakes? Solar winds? Can you tell me what solar activity will be like in 10 years?
"Everything that I am describing is standard and has been known for decades." How many times have we heard this, just before big leaps in understanding have occurred? Several times, just in my lifetime. It's hubris to believe we know that much about the weather.
I never said that we know everything that we need to. I've repeatedly pointed out that our models have big error bars on them, and there are long lists of things that we need to improve, of which your list doesn't even hit on the most important parts. But the fact that we have significant unknowns doesn't mean that we can't put order of magnitude estimates on our uncertainty, plug those into models, and come up with error bars. In fact that is how those models are developed, and how we develop error bars.
"Everything that I am describing is standard and has been known for decades." How many times have we heard this, just before big leaps in understanding have occurred? It's hubris to believe we know that much about the weather.
I said that after getting through a description of how the jet stream works, and was clearly referring to that description. I did not say - nor did I imply - that the jet stream is everything to do with the weather or climate. Important? Yes. Everything? No.
It is certain that there will be major discoveries over the next 20 years about how climate works. Why is Greenland showing far more melting than expected? How does soot from China affect everything from arctic ice to rainfall in the USA, and how does that affect climate? How much methane will be released as permafrost melts, and what will the climate impact of that be? These are all areas of active research.
But I'd be shocked if scientists 20 years from now disagree with scientists from 20 years ago about how the jet stream works.
What we do understand, on the other hand, tells us we should be extremely conservative when it comes to the environment, and avoid pumping it full of greenhouse gasses, because having the planet heat up may lead to really bad things happening.
I don't get this "We don't understand what's going on, therefore we can keep making a mess" argument that so many people seem to be making.
If evidence comes out, look at it, revaluate, repeat...
1. Likelihood in long term remains the same. (title betrays its readers) 2. In medium term likelihood of most extreme scenarios is less than what was expected. (hey ho, extreme scenarios are not to account for, thats why they are extreme) 3. people should be exactly as concerned as before about what climate change is doing
ANyway, the whole news-article is based on one publication. Meh. I would rather ignore the details of one publication because minor difference in details dont matter. The broad picture remains the same.