Climate models are running red hot, and scientists don’t know why
bloomberg.com
bloomberg.com
We are 100s of individuals from more than 30 national and international partner institutions with planes, drones, ships, ground stations and autonomous buoys trying to understand how and why these clouds form, how that links to their environment, dust from Africa, the ocean current, the jetstream aloft, etc. The positions of the different platforms can be seen live on the main website and the data we are producing is appearing on there too.
If you have any questions about what we're doing I'd be very happy to help or point you towards the right people :)
The main problem has never been a lack of science, the problem has always been (and alas, continues to be) a lack of political wherewithal to actually rapidly implement the drastic steps necessary to avoid the worst outcomes.
Maybe we’re finally getting what we collectively deserve?
Perhaps you should tell the people who are running the "big observational campaign happening right now" that they can pack up and go home.
Nate Silver’s “The Signal and the Noise” gives a much better description than I could do
Because the Earth is huge, data collection is expensive, and funds are limited. There is a lot of [literal] ground to cover and it's perfectly feasible to augment professional work with amateur data, now that pressure, temperature, and location sensors are relatively cheap and ubiquitous.
They don't, because of perspective. Even satellites in Geosynchronous orbits don't see half the globe. They are above the equator but they can never see both poles at once. Satellites closer than that only see a small part of the globe. A satellite would have to be infinitely far away to see an entire hemisphere at once.
A GPS satellite at 20000 km of altitude only sees 38% of the Earth.
https://www.wtamu.edu/~cbaird/sq/2013/05/10/since-one-satell...
† does this general strategy have a name?
https://www.climateprediction.net/
I used to work for them a few years ago.
The big worry is bias, a lot of assumptions about how physics can be approximated are needed to make these models, but there isn't time to test every combination of them at the full scale. So you do small scale tests and hope nothing unexpected happens in the full run.
For scale, a performance basline paper from 2018 reports achiving 0.23 simulated years per wall clock day using 4900 GPU cores [1].
[1]: https://www.geosci-model-dev.net/11/1665/2018/gmd-11-1665-20...
Why? Because experimenters who got the correct value figured it must be too high, and ran the experiment again until they got a more-erroneous value, one that was nonetheless higher. Eventually it worked itself out.
But climate modeling isn't measuring something objective and static like the charge of the electron. It's prediction. I'm afraid that the incentives are to credit models that predict more warming just a bit more than those which predict less; the expected effect would be that the predicted warming effect would get larger over time.
Please note that I'm not calling climate science a "Cargo Cult", as Feynman put it; I accept the basic premise of anthropogenic warming on first principles, and see that historic measurements (not to speak of recent ones) show a warming trend. There is cause to be concerned.
Nonetheless, it would be surprising if climate modeling, which is inherently inexact and involves irreducible guesswork, didn't drift toward the more alarming, due to similar social forces to those identified in Feynman's essay.
The oil drop results (Millikan was less than 1% off, by the way) show the pressure on scientists to conform with the current status quo, the pressure NOT to release shocking or unexpected results. In climate science, that means underplaying the results, biasing them towards less catastrophic findings, and there's a great deal of evidence that that is what has been happening. For instance, the gold standard climate documents, the IPCC reports, represent a consensus and therefore if 99% of scientists believe 100 units of climate change is coming, and 1% of scientists believe no more than 30 units of climate change is coming, 30 units is what is reported (the amount everyone can agree on). This is a huge underreporting bias, only slowly corrected with each new report.
Good on you for your scientific approach, you just basically reversed the signs in your equation.
To use your numbers, the IPCC reports that 99% of scientists believe 100 units of climate change is coming, and 1% believe no more than 30.
It's less than 200 pages, I recommend actually reading it, rather than just guessing how the sausage is made, as you've done here.
Why? Because experimenters who got the correct value figured it must be too high, and ran the experiment again until they got a more-erroneous value, one that was nonetheless higher. Eventually it worked itself out.
But climate modeling isn't measuring something objective and static like the charge of the electron. It's prediction. I'm afraid that the incentives are to credit models that predict less warming just a bit more than those which predict more; the expected effect would be that the predicted warming effect would only slowly approach the more dreadful reality.
Please note that I'm not calling climate science a "Cargo Cult", as Feynman put it; I accept the basic premise of anthropogenic warming on first principles, and see that historic measurements (not to speak of recent ones) show a warming trend. There is cause to be extremely concerned.
Nonetheless, it would be surprising if climate modeling, which is inherently inexact and involves irreducible guesswork, didn't drift toward the less alarming, due to similar social forces to those identified in Feynman's essay.
You're not actually saying anything of merit here. Flipping the sign on your paragraphs requires almost no work to get a meaningful result (which doesnt contradict known facts). You've made an assertion (climate models are likely to overpredict warming rather than underpredict) and handwave at some random shit that makes it sound nice. The actual assertion has zero argument behind it.
This actually doesn't make any sense! In your valued Milikan example, the problem was subsequent experiments were biased towards lower values, meaning that for climate models the bias would be expected towards under heating models. In other words, the lesson from Milikan is that there is a risk our models aren't heating fast enough.
So by the quoted example we should be worry that our models under predicts, and yet Milikan is stood up to argue the models are too wild in their warming predictions?
One recent example of such a dynamic was Germany's recent plan to phase out coal (by 2038). The committee that drew up the recommendations was overruled on several key elements, such as the decision to not to open a new coal power plant this year. Although the committee was and is correct that opening new coal power plants is not compatible with our CO2 emissions goals under the Paris agreement, which are in turn our best estimate of the maximum we can emit and still have civilization past the next couple decades, lawmakers didn't want to hear it.
You've got it backwards. The models are known to be conservative because "alarmist" scientists have received a bad reputation when they are proven wrong. It is safer to pretend to be ignorant and underestimate the numbers.
The big question is then of course whether the new cloud model is wrong and the temperature increase therefore as well, or whether the new cloud model is more accurate than previous ones and the temperature increase is a real effect.
I found another article that looks at this in a bit more detail:
https://news.ucar.edu/132678/ncars-new-climate-model-running...
The linked paper this is based on has the following as the last sentence:
> What scares us is not that the CESM2ECS is wrong (all models are wrong, [Box, 1976]) but that it might be right.
For this reason, I'm skeptical of models that try to simulate very complex systems with a lot of variables and feedback loops. Models that have a large number of variables are particularly difficult to get right because different tiny mistakes in various parts of the model can compound and yield completely arbitrary and contradictory results. Approximating the reality in software is almost impossible.
'Hopefully' is doing a lot of work there. In modeling a highly dimensional dynamic system it's not obvious that a smaller cell size will lead to more accurate predictions.
Not to diverge, but I'd be extremely wary of editorial bias/spin from this particular publication until November or so.. which is not to say that the topic itself is suspect - as you point out, the big question is if the updated model is actually worse than previous models or if it is better
Currently studying solar energy transfers via hot solar particles, latest hot topic.
> "So we can't throw them out yet."
This might be an elementary view of science, but I think there is a danger here that while everyone is making their models, if anyone is an outlier they go and tweak their model to match the patterns of others: 'Klaus Wyser’s group "switched off" some of the new cloud and aerosol settings in their model, he said, and that sent climate sensitivity back down to previous levels'. That seems to me a questionable reason to "switch off" part of the model - you should create the most accurate simulation possible and trust the output, not tweak the inputs to match literature data.
If your model produces wildly different results from previous models, either you hit on some really big discovery or you made a mistake. An ethical scientist will try to rule out the latter possibility before accepting the former.
One pretty general debugging/analysis strategy for a complex model is to deactivate it piece by piece until you get it to a point where it should reproduce a result that you can verify by other, independent means. E.g. tweak the parameters of the model so that reproduces a result that is known analytically. For instance, whenever it is possible in a model, a good sanity check is to set parameters that must lead to e.g. a perfect conservation of certain quantities.
And it does not make a credibility issue. This is how science works — it is a process that strives to be as accurate as possible, not come up with a static answer and stick to it (that’s what religion does).
The ability for science to change and adapt is what makes it so strong. That is the message that needs to always be driven when discussing science; not throwing hands in the air and saying “why do these scientists keep changing their answers? They obviously don’t know what they’re doing”
> The ability for science to change and adapt is what makes it so strong
To me this article is them _resisting_ change, looking for a reason NOT to accept it, because it goes against what they previously said. Maybe this is all to early, and in a year or so we will be seeing 4 or 4.5 degree predictions, but this article describes them trying to change their inputs to match previous answers, not getting new answers.
Just imagine they would go public with this "Scientists found climate change is worse than previously thought with updated model" and then weeks later find an error in the changes made to the model "Scientists made mistakes, climate change less severe than previously thought".
What do you think would hurt their credibility more?
They are not throwing away their findings and they are not burying it. They are working to valdiate/invaldiate them, because they are scientists.
Indeed, even people we nowadays consider brilliant minds of their time, encountered plenty of resistance [0] during these very same times because their proposed ideas just seemed too outrageous.
[0] https://en.wikipedia.org/wiki/Criticism_of_the_theory_of_rel...
What you're saying is that you have established a prior that undermines all further evidence presented to you, because it has changed substantially in the past. However, that seems irrational to me.
There are two basic modes of reducing pollution. Technological advancement, and conservation.
In the case of technological advancement, you get less pollution per unit of output as the same or lower cost. As long as capital is fairly cheap, these advances tend to propagate quickly through a competitive market.
In the case of conservation, it’s more a question of which groups of people should conserve (i.e. suffer) for this outcome, and by how much.
I'm seriously wondering why there is any reason to oppose technological progress at all. What can they possibly gain by sticking to the old technology? Who's going to benefit from something so short sighted?
We have known the rough level of the climate sensitivity (delta T per doubling CO2) in the current macro state for decades. We have observed it. This science is incredibly settled. We don't know where the tipping elements are and we don't know how the impacts will be distributed.
Questioning the credibility of people calling for action might look like you are being the circumspect and rational one, asking for action proportionate to the evidence. In reality you are endorsing an ignorant position that ignores the evidence we have. If this is not wilful ignorance then please read up on this. The IPCC report summary is a good spot to start. Sceptical Science also often provides good writeups: https://skepticalscience.com/climate-sensitivity.htm
The fundamental physics that drive the sensitivity are straightforward. Energy balance and water vapour. That gets you a ballpark figure that is confirmed by the last 100 years of emissions.
It is a denier talking point to claim that we just don't know enough, or that the models are always being tweaked and we should just wait until scientists have "the final answer" before doing anything.
Hey, let's stop giving NOAA weather forecasts because they aren't 100% accurate. Let's close down the stock market until everyone can decide what the values should be. Let's disband the military because not all military leaders have the same opinion.
If we are mature enough to recognize that imperfect but credible models are worth acting on in other domains, why do we hold climate change to impossible standards?
Given that, how could you possibly advocate for doing nothing?
> This is how science works — it is a process that strives to be as accurate as possible, not come up with a static answer and stick to it (that’s what religion does).
That's fine. Many public policy advocates throw around the term 'settled science'. But based on what you said, is there such a thing?
From the article:
Climate models have been doing a fine job projecting warming for a long time. A recent study compared models as old as 1970 with observations made in the decades since. Some models warmed up too much, and some too little, but 14 of 17 past projections turned out to be consistent with the measured path of global average temperatures.
Scientists can not give definite answers in such complex systems, but it is the closest we can get in extrapolating the trajectory that we are on and computing what the effect of various measures is.
I am not sure what else one could base policy on.
Yes, there is. Just because there is no absolute certainty, doesn't mean it's all just baseless speculation. Just because, as a matter of scientific methodology, atomic theory is not absolutely certain (i.e., we could hypothetically find evidence that contradicts the model), doesn't mean someone just made it up and it has no predictive power.
If you change your model (hypothesis) to fit the facts, your model is merely descriptive of the evidence that is already available, and useless for prediction - as proven by the act of changing the model. That's how science works.
If you want to cast it in the rigid hypothesis testing language (not a very good description of the actual practice), the description is this:
A physically motivated modification to existing tools lead to unexpected results that are not understood yet. As part of figuring out the cause of the new result they are running a series of smaller experiments to test various hypothesis of what aspects of the modifications matters most for the new results.
In effect, objecting to the practice of turning things off and on again is to object to the very notion of doing experiments, which is not very scientific.
To point out just how wrong your misinterpretation is, the very next sentence has the "why":
> A new research paper co-authored by Zelinka from the Lawrence Livermore National Lab likewise pointed to the role of virtual clouds in determining the results.
The key phrase being "role of virtual clouds." The motivation wasn't to slavishly reproduce results from the literature, and to even suspect that it completely outside the bounds of reasoned discourse. It comes across as if you are trying your hardest to find something to nitpick, some small phrase that you can misinterpret in order to raise doubts in those who aren't paying close attention.
This is exactly how denialists and propagandists behave.
I can't ding the climate scientists too much, though... I'm not sure there's a better way to study this stuff.
But I'm only a bit surprised this would be such a controversial opinion here.
If you are unfamiliar with climate sensitivity, this is a good place to start: https://skepticalscience.com/climate-sensitivity.htm
So we actually did an experimental test of the predictions made in 1970, and those predictions turned out to be largely correct.
We should probably halt this experiment on ethical grounds.
Sadly the political activists have hijacked the normal scientific process. And this allowed some pseudoscience (with alarming predictions or alarming observations) to mix in too.
In some science news I read that the Arctic Ice-sheet is growing back, and that Envisat showed that the oceans were not rising. So very likely the climate is more complex than some alarmed scientists thought.
[0]http://omegataupodcast.net/326-weather-forecasting-at-the-ec...
Like ignoring the whole climate change thing for a moment (though we absolutely should not do that), just the quality of life improvements to our health and well being this kind of mobilization would bring would be astonishing.
The wartime World War Two economy we learn about in school was only made possible because of two factors:
1) A massive surge in federal government spending, financed by borrowing from public markets (incl. war bonds), to buy the materiel needed to fight a war on two fronts (in Europe against Germany and in the Pacific against Japan). Such spending caused the public debt as a share of GDP to surge to its highest historical level ever, from about 40% at the start of the war to 100% at its peak, as you can see on this graph: https://upload.wikimedia.org/wikipedia/commons/a/a7/US_Debt_... . Today, without such a total war effort, we are running trillion dollar deficits. To put it as shortly and bluntly as I could, trying the same thing today would bankrupt the government. Our debt levels are far higher than they were then, in relative terms, and increasing by over a trillion every year. We would be looking at 2 or 3 trillion dollar deficits. Deficits of that magnitude might shake investors' confidence in the U.S.'s ability to service its debt.
2) The United States was coming out of the Great Depression, and the unemployed labor pool was in the double digits, as you can see on this graph: https://upload.wikimedia.org/wikipedia/commons/thumb/6/68/Un... . In other words, there were a lot of unemployed people with nothing to do who could quickly be put to work to produce stuff for the war economy. This is not the case today. The economy is running at full employment. The large spare labor pool that existed then doesn't exist today.
America has a large shadow labor force. People who do not regularly apply to work are not counted as officially “unemployed.” Have to take this into account.
It signals to me that people like complaining about things, but do not participate in politics in any productive fashion. Right now it's just team sports, and most people can not name the candidate they are voting for, outside of the presidential election, until they read it off the ballot.
Transport accounts for basically a third of U.S. energy use, though it has been hardly growing over the last few years, which is a good start.
The most efficient car, bus, or train, is the one that you didn't ride.
You would hope, but sadly it depends on what lobbying group they're listening to and what industries are employing their constituents.
The impact on quality of life and society would be "astonishing," but they won't be improvements. The Soviets and Chinese tried similar "mobilization[s]" for food production. The idea was to direct society's efforts to producing enough food for everybody. Tens of millions of people died of starvation as a result. It turns out that governments are bad at running economies.
I don't know why so many people think that the same mechanism (a command-and-control economy) will lead to a different result just because you change the goal from food or industrial production to climate change mitigation.
Think also new deal / public works projects like the Hoover Dam (many died working on the Dam but not because it was a government mobilization project). Just the government spending a bunch of money on environmentally focused projects could happen and could be good.
Um, sure it did? Killing a lot of people was, in a sense, the goal.
America's WWII mobilization is really nothing like the Green New Deal. The total cost of the U.S. war effort is estimated at around $300 B (adjusted for 2009 dollars) [1]. The lowest realistic estimates for the cost of an effective Green New Deal are around double that amount every year, and lasting for decades [2].
It's true that WWII cost far more relative to GDP (over a third, versus 2% for the New Green Deal estimate above), but expressing the cost relative to GDP is not very useful in this context; in 1945 the U.S. was poised to enter a period of ten percent annual GDP growth at a time that military spending was plunging. The situation now is completely opposite; the U.S. will possibly never sustain greater than 2% GDP growth, and the Green New Deal proposes to pull money out of that for decades to come.
The character of WWII spending was also completely different. That money was largely spent on things that were pretty much guaranteed to help the war effort; materiel, industrial infrastructure, and troops. There was little risk of misallocation.
In contrast, the Green New Deal is fraught with misallocation risk. In that way, I suppose that a comparison to modern military spending is actually quite appropriate.
1 - https://eh.net/encyclopedia/the-american-economy-during-worl...
2 - https://newleftreview.org/issues/II112/articles/robert-polli...
Extrapolating a general theory from just two examples seems like a mistake.
> Pollin, however, strongly disagrees with the resolution’s aim of getting to net zero with just a decade of investment. “I think it’s completely unrealistic and it’s not worth costing out,” he said of the Green New Deal.
$1 trillion is the price tag of a much more conservative approach that puts a much longer timeline on carbon reduction:
> Edward Barbier, an economist at Colorado State University, agrees that a strict timeline isn’t realistic. He advocates jump-starting the transition by investing about 5 percent of GDP over five or so years. GDP was $20.5 trillion in 2018, according to the Bureau of Economic Analysis, so that’s a little over $1 trillion a year. “That would push us on a path to clean energy, and a path that permanently lowers carbon emissions,” he told us.
The second point I want to make is that we have much less headroom to do a "New Deal"-style project than we did in 1930. We are actually already far in excess of New Deal-era government involvement in the economy. (See my link above.) Today, government spending is at around 35% of GDP. We are in fact closer to the "total war mobilization" of World War II (where spending peaked at 45%) than to the New Deal era 18%.
So the real lesson is not that command economies are bad but rather that unforeseen circumstances should be avoided. If they hadn’t killed the sparrows we would not now be hearing about how many died.
The Four Pests Campaign is a great example of humans suffering the unintended consequences of their own stupidity and hubris. However the Great Famine had many proximal causes, and there is no evidence that simply sparing the sparrows could have prevented it.
If we go to total war to prevent climate change, that means things like:
* Shutting down power and fuel supplies to poor countries that can't afford current solar or wind power
* Military conquest of uncooperative countries
* Bombing coal mines to shut them down
* Bombing oil fields so nobody can get the oil
* Slaughtering foreign civilians to reduce their carbon emissions
When I think of a "total war" caused by an emergency response to global warming, those are the sort of consequences I imagine. Let's hope we don't get to "total war".
Vast overuse of energy resources is a pattern intertwined with modern life, from housing to transportation to food to recreation. The people demand having a vehicle with more than 100hp at their whim. Now picture a herd of 100 horses for every person on Earth. It is political suicide to propose cutting down to ecological sustainable levels of 1 horse per person. That's before we take in account the population explosion of 5-10-20x compared to pre-industrial levels. Not sure where you even begin implementing policies to reduce the population levels to ecological sustainable levels.
As a species, we are simply incapable to comprehend that the way out of poverty is intelligent frugality. Instead, we attempt to brute force our way. The effort needed to fall back into an ecological sustainable band far surpasses WW2, and no one wants to hear about the actual costs. Nothing will change until mother Nature will do the change for us. The hard way.
In my opinion, these approaches completely fail at solving large issues that require large orchestrated efforts that require things at state, nation, and even world scale and longer timescales than an individual or their kids.
We haven't really developed a 'hammer' for those sort of problems and that hammer keeps competing with our 'saw' we use on the other problems whose proponents want to only use their 'saw' for every problem they see, ignoring its shortcomings.
The problem with climate change is that it is really expensive to fix with highly uncertain costs to do so.
So it's not expensive in any long-run calculation, only the short-run.
Nor is cost net negative if you use high discount rates and try lower co2 targets (e.g. 3 degrees warming by 2100 is much more likely to have positive ROI than say holding 2 degrees). Huge controversy around protecting against lower probability, highly destructive scenarios. Point is there's lots of controversy here.
https://en.m.wikipedia.org/wiki/Economics_of_climate_change_...
Comparisons to a war are overly dramatic because it puts the destruction on the opposite side of the effort. If you're in a war and two countries spend a trillion dollars fighting the war, those resources go to causing trillions of dollars of damage to the other country -- most of the cost of the war is getting bombed, not making bombs. With climate change it's the opposite -- the more we do against it, the less damage there is overall. On top of that, most of the "costs" are just replacing other costs -- you have to spend money building solar panels, but then you don't have to spend money doing oil exploration or mining coal, which offsets most to all of the cost.
On top of that, wars are characteristically fought by governments with all the bureaucratic inefficiency that implies, whereas the single biggest thing we could do against climate change is to accurately price carbon and then let the market find the most efficient way to optimize it out.
Obviously that doesn't get us out of actually doing it, but the biggest problem isn't that it's actually that hard from an economic perspective, it's that it's hard from a political perspective because the oil industry has a trillion dollar interest in not ceasing to exist.
> While it is true that we estimated damages as high as 10% of GDP annually at the end of the century for warming of 15°F above pre-industrial levels, the odds of a temperature change that would drive damages of this magnitude are slim. In fact, they are less than 1-in-100 by our original calculation. Under a scenario of continued growth in global emissions, 9-out-of-10 global change temperature projections fall approximately in the range of 4°F to 11°F by 2100. The median change is closer to 6°F. We deliberately incorporate tail risks in our research, not just “most likely” outcomes, because consideration of tail risks is crucial to sound risk management.
> In other words, if global GDP doubles or halves by 2100, the results suggest real GDP per capita would still be 7.22% below where it would be otherwise.
For most of the world, an RCP8.5 scenario is equivalent to knocking out 3-4 years of GDP growth. Bad, but not catastrophic, and probably less bad than the impact of "WWII-style mobilization" and shifting the economy into command-and-control mode.
> Our localized approach to studying the relationship between climate and society reveals that the burden is spread unevenly. In many counties, GDP decline could total more than 10% by 2100, and in the worst-hit county, Florida's Union County, losses could near 28% for a likely warming scenario under continued emissions growth (the 7°F median change, not the extreme 15°F change highlighted in press coverage). The combined tally almost certainly understates the extent of the damages, because the worst effects are concentrated in places where incomes are lowest. Tumbling incomes in poor counties have a correspondingly small impact on nationwide GDP, meaning the economic burden of climate change is reduced because it falls on those with low incomes.
> If the burden is spread evenly, 1% or 2% of national GDP might seem manageable, but we will not all be equal in the face of climate change. Across the United States, there will be winners and losers. What is lost in all of this noise is the sad fact that even those smaller numbers are too high a cost. They come from a subset of outcomes that are well-measured. As ever in this debate, it is important that we look beyond the headlines, beyond the averages, and examine the people at the heart of the issue. Look at the mass of evidence that points to people who will actually be negatively affected by climate change. They are not abstract people not-yet-born and in some far-off land. They are your neighbors. They are your friends. They are you. Combining local climate projections with historical observations yields a personalized, evidence-based outlook of future risk. Our ongoing research is mapping out these local impacts across the globe.
That sounds pretty catastrophic.
[1]W. Nordhaus, “Projections and Uncertainties about Climate Change in an Era of Minimal Climate Policies,” American Economic Journal: Economic Policy, vol. 10, no. 3, pp. 333–360, Aug. 2018, doi: 10.1257/pol.20170046.
edit: This comment is currently sitting at -2. If you think a 1.5° target is optimal, you should explain why you think so rather than just down voting this post. The paper I linked to is by William Nordhaus who won the Nobel Prize for economics in 2018 for his work related to the economics of climate change.
Having worked with complex geologic (not climate) models in the past, this is the part that gives me pause. The scientists have set out as a first principle to find warming and then are working backwards and, ostensibly, everything is legitimate because model results are calibrated to previous real data.
But here's the problem. When you have complex, chaotic models with hundreds of freely tweekable parameters, it's fairly easy to fit data and simultaneously get any future prediction you (or your bias) want. Even when individually each variable is within a reasonable range.
We arguably have proof of this happening - climate models have been consistently overpredicting dT for what, 10 years now? There is an institutional problem with climate science, in that there is no real penalty for being wrong, and in fact the more aggressive results probably get the most attention. Because the modeling is so far removed from any sort of experimental or observational data collection, I think the field is dangerously susceptible to institutional bias.
> One question modeling can help answer is called “climate sensitivity,” an estimate of how much warmer the planet will be once it has adjusted to atmospheric CO₂ at double the pre-industrial level. (At current rates, CO₂ could reach a doubling point in the last decades of this century.) This is the old, reliable number that’s come out to 3°C for 40 years. It was as close as anything gets to certainty.
I'd be curious where your impression comes from, in terms of what sources of information you're receiving.
I think 5 out of 8 is not a very strong difference from 4 out of 8, which is the comparison that makes sense in this context.
Perhaps literally all historic climate models have been accurate, I've read extremely enthusiastically received articles suggesting as much.
There’s probably been a collective tendency to (try) to view what was coming our way through rose-tinted glasses, some unconscious effort to lowball the projections in order to have a less catastrophic outlook. Maybe the computers models are finally beginning to converge on a more realistic scenario as they factor in the actual changes that have occurred so far.
It has never ceased to amaze me how we have oodles of science fiction films that feature a lone astronomer spotting an incoming asteroid and that then segue into the whole of humanity pulling together to build a fleet of spacecraft to flee on or thermonuclear weapons to blast the thing out of the sky with, but in reality we’ve had people warning us of approaching doom for seventy years and haven’t managed much more than a collective “YOLO LOL”.
I have some experience in sensitivity analysis on stochastic systems such as climate models, and it seems to me that feedback loops are probably becoming increasingly tightly correlated, which in my field (macroeconomics) tends to herald massive discontinuities.
I am not at all happy about this. At all.
I finally decided to do something about it last fall. I researched and have committed to purchasing green power. Every month I purchase 850 kWh for $22 from Bullfrog Power (a Canadian company, I have no affiliation). It's much more reasonable than I thought. I still conserve as much as I can but $22/month allows me to feel like I am doing something. If in 40 years, my kids ask me what I did to prevent climate change, I feel like I'll have an answer I'll be proud of.
Have you considered your next step, and do you have any suggestions? Purchasing green power is such a minor sacrifice for my household, I'm still looking for something more.
Trying to solve it on individual goodwill of course helps but is not enough by itself.
Doesn't it kind of feel like this is the equivalent of a kid in the 70's asking why their parents didn't stop World War 2? We absolutely need to be as vocal as possible, but as individuals, outside of trying to get people with power to affect the change we need, I don't know what we can expect to accomplish. You just can't do enough diet modifications, carbon footprint reduction, or recycling to have it matter on a global scale.
I used to think like that. I used to think "There's nothing I can do, why do anything." Then I had kids and I realized that I need to be able to tell them I did something. Our world might be a wasteland of burnt forests and flooded cities, but at least I will be able to look my children in the eye and say "I tried."
You can follow this logic all the way down to an individual level.
If China doesn't do anyting, the US doesn't have to do anything either. If the US doesn't do anything, Germany doesn't have to do anything either. If not Germany, then not Munich. If not Munich, then not our little town. If not our neighbor, then me neither.
Everybody and every country should do whatever they can. Will it be enough? Probably not. But you gotta start where you actually have some control.
Don't fall into the trap that there's no reason to change your own habits because you think individual action doesn't matter. It does. But you're also right that it isn't enough.
[1] US EPA, 2017, "The transportation sector generates the largest share of greenhouse gas emissions. ... The largest sources of transportation-related greenhouse gas emissions include passenger cars and light-duty trucks, including sport utility vehicles, pickup trucks, and minivans. These sources account for over half of the emissions from the transportation sector." https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emis...
[2] Same source, 29% of emissions from Transportation; more than half that from commuter cars.
I honestly struggle to understand this statement in the context of discussing individual action. Making public transit a reasonable option for most personal transportation in the US would be a public works project on the scale of the New Deal.
Perhaps more importantly, cutting US emissions by 10% is very nearly inconsequential unless it is part of a coordinated effort that is driving global emissions down by significantly more than 10%.
I don't agree. Most large-ish cities already have quite good public transportation networks, but outside of a couple special places like NYC, Chicago, and maybe SF, they're not the default option. If the demand is there, adding more bus routes and increasing frequency is trivial. Adding more rail and subway lines is definitely a major task, but we spend more on garbage like the TSA and the F-35 than we do on increasing public transit options; it's hardly a task on the order of the New Deal.
My overall point is individual action is a major factor in transit emissions, which is a major source of carbon, and thus individual action does have an impact on our climate change future. The fact that individual action alone isn't enough to fix the problem isn't an excuse for individuals to avoid making choices to lower their emissions.
> Perhaps more importantly, cutting US emissions by 10% is very nearly inconsequential unless it is part of a coordinated effort that is driving global emissions down by significantly more than 10%.
I don't agree at all that decreasing US emissions by 10% is inconsequential[1], but yes, of course, it is not enough. I already agreed with you that individual action is not enough. But it is significant. I'm trying to back up that assertion with numbers.
[1] Ten percent of US emissions is about 1.37% of global emissions, https://en.wikipedia.org/wiki/List_of_countries_by_carbon_di...
That's because the power companies want to keep people from developing competition to them... if enough individuals install solar plants with battery storage, eventually they power company simply won't be needed any more, which is what they're trying to avoid.
By selling "green" feel good power, they quiet the impulse that people like you get to make changes that would impact their business.
It's still good that you choose to purchase green power over e.g. coal fired power, but it's also the power companies you're keeping in business that are causing a lot of climate change, and who have contributed to it all along.
edit: also it is very rare to have the externalities included into the sum of CO2 emissions (dams need cement, wind turbines need steel, solar panel need mining, we need to transport these components, etc. -> all of that is probably not currently powered by CO2 neutral energy).
Is there a typo somewhere? I run multiple computers at home 24/7 and I'm using ~2500 kWh a year. Also, 850 kWh for $22 sounds crazy cheap, I pay ~100€ per 200kWh (including the rented meter, but more importantly, taxes).
That too, yeah. Though they are primarily subsidized by not paying taxes on energy, they're not paying negative prizes (yet).
The impact of cloud cover in these models has been incorrect, and has such a large impact. Doesn't this strike anyone as a major problem?
We're burning about 100 billion gallons of aviation fuel per year.
> This means each gallon of jet fuel (6.5lbs) will combine with 23lbs of Oxygen and turn into twenty pounds of CO2, and just over nine pounds of water! (see: https://paullaherty.com/2015/01/10/calculating-aircraft-co2-...).
So that's 100B gallons * 9lbs is about a half a billion metric tons of water vapor going into the dry upper troposphere annually from commercial aviation.
Which, evidence would seem to suggest, has not been modeled properly (at all?) by these climate models?
If I was producing these models, I would be embarassed.
> It turns out simulated clouds often cause headaches for climate modelers.
to
> Which, evidence would seem to suggest, has not been modeled properly (at all?) by these climate models?
Embarrassment may be premature
Let's check it out it percentage terms. According to wikipedia, the mean mass of water vapor in the air is 1.27 * 10^16 kg. To get the units correct, that aviation contribution is 5 * 10^11 kg. Dividing the latter by the former, we find that the annual commercial aviation water vapor represents 0.004% of the mean mass of water vapor.
That's rounding error.
Your number "about a half a billion metric tons" is 0.5 × 10^12 liters of water, which is 5 orders of magnitude lower number. Or, less than 1/10 000 of atmospheric water.
To say in your words, "If I was quoting this number as a significant contribution, I would be embarassed."
Almost none of that atmospheric water resides at FL300. That's the point. You wildly adjust atmospheric parameters in the real world, with (apparently) not accurately accounting for them, and then claim your model is predictive?
This is why modelling complex, chaotic systems is hard. I've done it, and that's why I would be embarrassed.
Not because of the mistakes. Because I was so certain that my models were correct. The level of hubris displayed here is mind-boggling.
It's in no small part due to "solar weather" (sunspots), and long term levels of high-level water vapor:
> Contrails during day cause cooling because of reflecting of sunlight back into space. During night, they trap infrared heat causing heating. So it is a balance between the two time intervals. We would like to have more CICs (contrail-induced cirrus clouds) during day and none during night.; FAA Scientist: We Want Clouds By Day, None By Night
https://www.ted.com/talks/allan_savory_how_to_fight_desertif...
> The simulations showed that the rate of Arctic warming in a world without CFCs would be cut in half – a striking effect for a category of substances that are only present in small quantities to begin with. To ensure the result was not simply a quirk of the simulation, the researchers ran the experiment using two different climate models and arrived at a similar outcome.
https://www.theglobeandmail.com/canada/article-cfcs-are-a-ma...
The danger here is that there's something else we fundamentally don't understand about the atmosphere.
[1] https://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.h...
It's unlikely IMHO that floating point rounding oddities would cause catastrophically erroneous results. In my experience from other physics simulations, you usually validate some known behaviour you're not trying to predict, e.g. that energy is conserved, or that total mass of fluid is conserved. Bad numerics will usually violate these conservation laws, so you can use the fact that they are conserved as some evidence that your numerics are actually solving the differential equation relatively correctly.
Basically, people would notice broken numerics in this case.
There are situations where it is harder to validate numerics (e.g. if your numerics inherently conserve some quantity by construction, then you can't use it to validate the behaviour of the numerics), and to be sure, a concerning fraction of all publications with numerical results contain mistakes.
But I don't think floating point rounding is near the top of the list of issues to go looking for in these models.
I always hope that if heatwaves keep coming summer after summer, governments/the UN will take tough decisions.
If nothing is done and summers are too hot, I clearly see people protesting/striking/blocking roads/etc until governments concede. My biggest fear are consumers that will refuse to adapt their consumption because they will see this as unfair rich-vs-poor restrictions. People addicted to consumerism would easily riot to denounce how capitalism ruined their living standard.
Last summer when there was a heat wave here, lot of people bought ACs. Next year, they are also switching them on when it's 30 degrees Celsius outside.
The irony.
Which, in all fairness, it is. It's not like e.g. miles travelled is similar for everyone in any society. You have the upper class with multiple international vacations (usually via airplane, cruise ship etc), you have the middle class with maybe one trip per year to a foreign country, and you have the lower classes with maybe one trip every five or ten years. "Everybody just has to cut one trip a year" really is different for the rich vs the poor, isn't it?
The same is true for many related issues. It's not the poor families that own two or three cars (because you sometimes need a small car, can't take your SUV everywhere).
What's true is that the masses will have a large impact simply because they exist in large numbers. What's not true (by a long shot) is that they consume anywhere close to what the rich consume.
Basically, the backtesting failed to match reality for the recent past, they tweaked parameters to get it to fit, and that produced surprisingly high predictions for the future. I don't think that would leave them anything to backtest on, since they'd used effectively all their historical data to fit the model to.
There’s a nice article here on the issue and frustration of clouds for climate modelers by the head of the Royal Meteorological Society here: https://www.carbonbrief.org/guest-post-why-clouds-hold-key-b...
Ironically, socialism is being sold as a solution that you yourself make very clear. That, the pace of scientific progress is really fast ,and automation is going to make a lot of jobs obsolete.
Socialism (in the nordic sense, ie. capitalism with social welfare) is being proposed as a solution to rising inequality and unregulated for-profit forces in the free market of industries where the consumer has no choice. (medicine, education)
So it's not an issue of versioning (I assume they could reproduce the old results using the old data).
Could you explain this a bit more? Are you talking about data assimilation?
All PDEs are solved numerically by discretizing them into linear or nonlinear systems. If it's convex enough, Tikhonov regularization is often used.
Linear PDEs, where the solution depends only linearly on its derivatives, can be discretized into matrices. This gives a system like A m = d, where A is the discretized PDE, m is the "model" or parameter values, and d is the data. This is usually over or under-determined from the data, so it has to be solved by least squares. Since the resulting system is usually almost singular, regularization is applied, usually by penalizing the L2 norm of the model:
min || A m -d || + r ||m||^2
If it's nonlinear but convex enough, one can just solve it by fixed point iteration, with the above linear equation being solved at every step (Newton's method often doesn't work well). If it's too nonconvex, then MCMC or other Bayesian methods are better, since a single solution is useless if the parameter values could plausibly around widely separated minima.
Typically we know the basics of the physics, i.e. conservation of energy, momentum and angular momentum which set up the equations. But there a number of constitutive laws which relate parameters between these are "machine learned" but in generally, they are typically linear relations.
https://addons.mozilla.org/en-US/firefox/addon/temporary-con...
Disabling scripts generally doesn't break these types of sites but it does stop them from detecting whatever it is they are trying to detect.
They are educate guesses or educated estimates to be more charitable. Our computing capabilities are much too weak to accurately model systems as complex as the entire earth's climate.
We have a lot of data measured at many points on Earth spanning many decades. The data clearly shows that our planet is warming up and that there is a strong correlation with greenhouse gasses. One can extrapolate from these data points with certain reliability.
What is hard is to take into account are tipping points (which is why the IPCC excludes them in their projections), such as the effects of methane release from warming tundra soil. As far as I understand, most known possible tipping points only make things worse, not better.
At this point the question is not if climate change is happening (there is near universal agreement on that among climatologists), but whether it will be bad, but manageable, it will be ugly, or life-threatening to mankind. In any of these cases, we have to act now.
In the terms of "bad, unmanageable" climate change, I would invite you to research the early Holocene, which had temps as much as 7 degrees hotter than modern temps. The early Holocene began about 12K years ago and ended about 6K years ago. The warm temperatures correlate with boom times for humanity.
See: Early Holocene Temperature Oscillations Exceed Amplitude of Observed and Projected Warming in Svalbard Lakes
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201...
I'd say all of thinking is based entirely on experimenting with mental models. Are you saying your thinking is invalid? :))
The article talks about it a little bit about how the models are used to predict the 19th century to see if they are correct. But the models use the last 100 years as input so of course it will give you accurate output. But the real challenge of the models would be to accurately predict things that are not part of the inputs into the model. I don’t believe that these models can do this and are thus an exercise in straight extrapolation based on very complex and interconnected inputs.
What makes such a measurement an "invalid form"?
The measurements are real, and there is an established history of the models being generally correct (if not in specific details) by now. Climate study is not the new science you seem to think it is.
Can you point me to one such model? One that actually predicted temperatures correctly back in the 1970s and not after various recent "adaptations" like "corrected" emission data?
> The measurements are real
Yes, measurements are real. Interpolations, resulting "global" temperatures and predictions aren't.
HadCRUT4 (from UK Met Office Hadley Centre and the University of East Anglia’s Climatic Research Unit)
GISTEMP from the NASA GISS
MLOST from the NOAA
JMA from the Japan Meteorological Agency
I'm open to other datasets. I'm not choosy.
I believe that the noisy measure goes up, on average, because it is (noisily) measuring a warming climate. I'll make that bet every year, and I will come out ahead...
using the trend line, you could set odds at which the betting on a colder 2021 would be the correct bet - but it isn't 50/50, which it would be if the process were random noise.
as a professional poker player I'm not surprised by this argument, but I am saddened.
edit: do you actually not understand the basics of statistical inference? this is like, middle-level high school math.
Good luck with that, but you first asked about one year (next year), which is a different matter altogether.
> (edit: do you actually not understand the basics of statistical inference? this is like, middle-level high school math.
I completely understand your point and how you are trying to move the goalpost from an easily refutable argument to something more useful. Perhaps your "professional poker player" mind doesn't understand that recent increases/decreases in temperature averages affect next year's weather, whereas past poker games don't affect your current one.
I don't think any intellectually honest person is indifferent to this bet. Everyone believes there is a solid chance that the climate is actually getting warmer, and almost no one would wager serious money at even odds on a globally colder 2021.
If you wouldn't bet against the climate getting warmer, then I don't think you have any place calling yourself a "climate change skeptic"
In a similar vein, I invest in index funds because I'm not a market skeptic. The market (at the moment) tends to grow year over year. I put my money where my mouth is in the market, I'd do the same on global temperature, and I'd win (on average, if I bet year over year, unless something changes dramatically).
The climate isn't getting warmer or colder just because next year's temperature does.
Climate is a physical phenomenon which can be modeled. One problem is that humans have an effect on the climate, so models can't predict how much effort humanity is going to put into averting that change. Since that aspect can't be modeled, they produce different projections for multiple cases of human behavior: business as usual, modest efforts to change, aggressive efforts to change.
Start here: https://skepticalscience.com/empirical-evidence-for-co2-enha...
Then proceed to intermediate and advanced. There are a TON of citations for your perusal. After your are done with that, the comments have some additional insights.
Have fun. This is quite the rabbit hole to dive into.
What was the CO2 ppm in the early Holocene? Why was the early Holocene so much warmer than today in spite of lower CO2 concentrations?
Early Holocene Temperature Oscillations Exceed Amplitude of Observed and Projected Warming in Svalbard Lakes
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/201...
Here's one of them from that page, chosen at random: https://www.tandfonline.com/doi/abs/10.5589/m04-044
A blog page linking a bunch of academic papers is as good as a hackernews comment linking a bunch of academic papers.
Your linked paper is about arctic temperatures, not global average temperatures.
In realize, we need fewer cars, more trains, better transport options, cell phones that last 8 years and that are repairable rather than 1.5 year planned obsolescence Internet of Trash devices.
The debate over climate/CO2 is a religious ideology at this point, and a very unhelpful one at that.
Taliban
If I throw a ball to you, your ability to put your hand approximately where it's going to be and catch it is "extrapolation based on very complex and interconnected inputs," and as it gets closer you're able to improve based on additional input.
Sure the models could all be wrong, we could be on the brink of a new ice age, and that ball could suddenly take a sharp right turn and accelerate. I wouldn't recommend putting all your money on either of those as a bet.
You don't have to believe the models:
Climate change is happening right now, with effects that are observable as trends across the globe. Even the most optimistic model is predicting widespread catastrophe.
The models differ in the scale of how bad it's going to be, not on whether it's going to be bad. Your stance is kind of like saying "Well doc, you're telling me I have sepsis, but you can't tell me how bad that's going to be so I'm refusing treatment until you can improve your models."
Pascal's wager has no information. You know nothing of the state of god's existence.
The precautionary principle uses current equalibrium as the default.
The current working equalibrium embeds information.
The precautionary principle does not state it will result in the best outcome. Only that it's more likely to not have the worst.
Having said that, the reality remains that, even without the models, the CO2 levels are increasing, they are well correlated to temperature increases, and they are expected to increase further - so VERY PROBABLY - climate change is a very serious massive problem. This is all true even without the models.
When it comes to the reliability of models, the devil is in the details. ...but, of course, no one should assume that a model turning out to be wrong or biased suddenly negates all the other evidence we have. Models are just one piece of a probability decision tree we need to navigate.
Does "they" refer to all models?
The main article's set of models are different than the ones referred to in another link someone in this thread provided, and I suspect the article you've linked will also use yet another unique set.
If it was me trying to persuade people, and all historic climate change models did indeed work really, really well, I'd make an authoritative web page that lists all of these models including their inputs and outputs, and show a detailed quantitative comparison of their outputs. I would think this approach would be more persuasive in multiple ways than hundreds of separate articles written in a narrative style, lacking numbers and consistency in sets of models.
We don't need any climate models to know that Earth is warming. We can tell that just from what we know of: how electromagnetic radiation works, the basic thermodynamics of gases, determining isotope ratios of the carbon making up a sample of CO2, how much solar energy falls on the Earth, the mechanisms by which energy can leave the Earth, the amount of energy leaving Earth as measured by satellites.
That's enough to allow verifying that:
(1) a net heating of the Earth taking place,
(2) this is mostly caused by humans (mostly be emission of greenhouse gases from fossil fuels) (and yes, we can tell the difference because emissions from burning fossil fuels have a different carbon isotope ratio than other sources), and
(3) it is getting more extreme.
All you need climate models for is to try to figure out where the extra heat will end up and what it will do there.
> they don’t like it
Who? HNers? I don’t care. I think it more that people don’t like seeing themselves as the virus or cancer, when we could easily change our behavior and we wouldn’t be.