The way scientists have unravelled the complexity of the climate system over the ages never ceases to amaze me. It shows what humans are capable of doing.
The next project should be a political system that does away with politicians.
It's too bad that we are running this particular experiment but I do appreciate the chance to look over the shoulder of scientists as they try to understand real-time data.
Modeling public opinion and all the forcings involved would make climate models look simple. But I think people in the highest Offices throwing the climate issue to public opinion to decide, where every element of it becomes contestable was a profound abrogation of their duty and betrayal of trust. Add in deliberate encouraging distrust in the science based expert advice - by people who have had unfettered access to experts and resources to assess it's validity as well as the duty to take it seriously - and it goes way beyond mere negligence. As a blanket term - corrupt seems to be the best description.
I think the relationship of politicians to policy is more like the relationship of fine food to toilet paper.
But my question is, will decent Americans get out and vote for Biden because they realise the need to keep Trump out, or will they feel an overpowering need to punish him and stay home.
The message of climate science is that the globe is warming, it's anthropogenic, and it's already taking a toll in homes, livelihoods and lives. The message of economics is that collective, i.e. government, intervention in the energy market is needed to cap the cumulative cost of warming, by replacing fossil carbon with renewable energy throughout the global economy. Of course, anyone who prefers to proceed toward that goal rather than resign themselves to open-ended costs in money and grief, must consider the political possibilities.
In the US, the Republican Party adopted climate-science denial as a firm plank at least 20 years ago, and has successfully branded climate-science supporters as 'libs'. The Democratic Party is at least willing to pass (without a single Republican vote) the somewhat-cynically named "Inflation Reduction Act" of 2022, which flawed though it may be, is the most significant climate legislation in 35 years. For US voters, that makes electing Democratic candidates the correct course, at least until some Republican candidate is willing to publicly defy their party. Supporters of alternative political courses are obliged to explain how they'll acquire the power to implement their proposals.
Oct 31, 2023Liked by Zeke Hausfather, Andrew Dessler
I clicked on your hot model paper and saw that Kate Marvel was a coauthor. The name sounded familiar and then I put two and two together and recognized the name from some recent interviews by David Wallace Wells at NYT, e.g.
Kate Marvel is indeed great and, like Zeke, an excellent communicator on the science and modelling of climate change. She has a TED talk from 6 years ago, but I really like this interview on TVO. It’s a great primer on climate change with clear explanation of key concepts like forcings, feedbacks, and tipping points. https://youtu.be/kZNAlEPMrOY
Kate is awesome, and is leading our chapter in the upcoming US 5th National Climate Assessment. Its been a lot of fun working closely together on that over the past few years.
FYI, I found your BTI article from 2019 and yaleclimateconnections article from 2016 on natural gas so I think I have the answers/information was I looking for - a quick aside the figures for GWP are very slightly different in the two which I did not understand. BTW, did you see that McKibben had an article about LNG in the New Yorker yesterday, https://www.newyorker.com/news/daily-comment/a-smoking-gun-for-bidens-big-climate-decision ?
Would it be correct to say that the models are broadly correct on a global average basis? Most of the outliers we have seen recently are more local (like the North Atlantic) and those outliers really get averaged out when looking at the entire globe.
Has this blog discussed the 2019 Perspective by Palmer and Stevens in PNAS, titled "The scientific challenge of understanding and estimating climate change" (https://www.pnas.org/doi/pdf/10.1073/pnas.1906691116)? From the introduction:
"As climate scientists, we are rightfully proud of, and eager to talk about, our contribution to settling important and long-standing scientific questions of great societal relevance. What we find more difficult to talk about is our deep dissatisfaction with the ability of our models to inform society about the pace of warming, how this warming plays out regionally, and what it implies for the likelihood of surprises. In our view, the political situation, whereby some influential people and institutions misrepresent doubt about anything to insinuate doubt about everything, certainly contributes to a reluctance to be too openly critical of our models. Unfortunately, circling the wagons leads to false impressions about the source of our confidence and about our ability to meet the scientific challenges posed by a world that we know is warming globally."
I take that to mean "don't overlook the shortcomings of current models, but consider your audience."
Zeke, as you point out, for the CMIP6 models they use historical data up to 2015.
As a result, your post-2008 graphs are a joke, half historical, half future. You are NOT looking at how well the models do at predicting the future.
And if you look at that, at how they predict the post-2014 trends, the models are doing HORRIBLY, running almost twice as warm as the real world. So you've clearly cherry-picked your starting point.
Next, I do love the part where you say:
===
"CMIP6 contains a subset of models that are running quite hot (>5C climate sensitivity per doubling CO2) that generally do a poor job of representing historical global surface temperatures.
For this reason, the most recent IPCC report created Assessed Warming Projections that weight the CMIP6 ensemble by its performance in matching historical temperatures, and tend to show future warming more in-line with the prior generation of climate models (CMIP5)."
===
Gosh, Zeke, so you're telling us that if you throw away all the models that do a very poor job of modeling, the rest of the models do a wonderful job of modeling?
Really? That passes for a scientific argument on your planet?
Finally, you've put up the historical hindcasts of the models as if they meant something … but you're totally ignoring a curious fact about these '100% physics based' models, a fact pointed out by Dr. Jeffrey Kiehl in 2007 and resolutely ignored by climate scientists since then.
These model have radically different values for climate sensitivity, varying by a factor of four, from about 1.5 °C/2xCO2 to 6°C/2xCO2 … and despite that, they can all do a pretty dang good job of hindcasting the past.
Say what???
Simply put, that would not be possible if these models were actually "physics-based" as the modaholics claim … but they're not. They are a collection of kludges and tuned parameters that are carefully adjusted, rewritten, and put under pressure until they can hindcast the past.
But as the post 2015 data above shows, they are really bad at predicting the future.
That should come a no surprise. In the US, stock brokerages are required to put a disclaimer on their ads saying something like "Past performance is no guarantee of future success" … climate models desperately need the same warming.
In short, this might make a great high-school paper about models. But it ignores the real failings of the models, and just spreads peanut butter over the glaring gaps in the logic, the use of egregious cherry picking, the discarding of models that don't fit the party line, and the clear lack of any actual physics basis for the models.
TL;DR Version?
Would not recommend.
My best to all, including Zeke. He's a genius meteorologist, but unfortunately, also a craven apologist for the Tinkertoy™ models.
I am left curious why CMIP6 performs significantly worse CMIP5. We know sensitivity is not 5C, so why are hot-running, poor postdicting models even included in the ensemble? I would think it better to focus on the top 5 or so most accurate models and vary initiation parameters to fill out the stocastic grey envelope. Over time modeling should get better not worse!
Well, the traditional approach has been model democracy. But as we argue in our Nature piece, the issues with CMIP6 (and the choice of the AR6 to develop its own weighted ensemble for Assessed Warming Projections) show that approach is outdated.
Nitpick re “we would expect roughly one in 20 months to be above the 95th percentile range if models are accurately representing real-world variability.” Shouldn’t that read “… outside the 95th percentile range …”?
I've updated it to be clearer and just say we expect one in 20 months to be above the 95th percentile (since I'm actually showing the 90th percentile range, from p5 to p95).
You're welcome. But the baseline of Zeke's graphs is chosen to quantify changes in GMST over the period of interest. Choosing a different baseline affects the total amount of change, but not the rate of change during that period. Does that help?
Yes. Thank you. I am very interested by the present question of, if there is an "acceleration" of the temperature increase, does the model of the paper will be able to match the observations. The conclusions is "yes" for the moment in the paper. Will the model remain consistent as it is said until now !
Also, what are your thoughts on the documentary by ABC news “Earth 2100”? It depicts a rather scary future where we do indeed collapse by then, but with believable reasons. Take a look, it’s both worrying and interesting!
There is so much misinformation out there and even good people like Andy Revkin get taken in by people like Roger Pielke Jr., https://substack.com/@revkin/note/c-44555537 . My biggest problem with the 'Low Hanging Fruit' post by Roger is that Roger claims that if we replace 5% of the worst coal plants would with nuclear we will decrease emissions by 9 Gt per year. That is so wrong on so many levels especially since global coal power generation emissions are about 10.5 Gt / year. His analysis is predicated on the erroneous paper by Grant et al. I estimate that at best getting rid of the worst 5% would maybe save 8% of the emissions caused by coal generation, .84 Gt / year - Ref. https://www.nature.com/articles/s41893-019-0221-6 .
I refuse to subscribe to THB just to call him on it.
I changed my mind, paid for a month subscription at THB and posted my reply correcting RPJ’s analysis of CO2 abatement costs between nuclear and the IRA. It was well received by Roger and he was appreciative. He wants to write a paper together. I’m not interested in doing that but maybe I did some good in a very small way.
My abatement costs are still way too high compared to what I see elsewhere for abatement costs of CO2. I would like to understand how traditional abatement costs are calculated.
The way scientists have unravelled the complexity of the climate system over the ages never ceases to amaze me. It shows what humans are capable of doing.
The next project should be a political system that does away with politicians.
It's too bad that we are running this particular experiment but I do appreciate the chance to look over the shoulder of scientists as they try to understand real-time data.
Modeling public opinion and all the forcings involved would make climate models look simple. But I think people in the highest Offices throwing the climate issue to public opinion to decide, where every element of it becomes contestable was a profound abrogation of their duty and betrayal of trust. Add in deliberate encouraging distrust in the science based expert advice - by people who have had unfettered access to experts and resources to assess it's validity as well as the duty to take it seriously - and it goes way beyond mere negligence. As a blanket term - corrupt seems to be the best description.
I think the relationship of politicians to policy is more like the relationship of fine food to toilet paper.
But my question is, will decent Americans get out and vote for Biden because they realise the need to keep Trump out, or will they feel an overpowering need to punish him and stay home.
The message of climate science is that the globe is warming, it's anthropogenic, and it's already taking a toll in homes, livelihoods and lives. The message of economics is that collective, i.e. government, intervention in the energy market is needed to cap the cumulative cost of warming, by replacing fossil carbon with renewable energy throughout the global economy. Of course, anyone who prefers to proceed toward that goal rather than resign themselves to open-ended costs in money and grief, must consider the political possibilities.
In the US, the Republican Party adopted climate-science denial as a firm plank at least 20 years ago, and has successfully branded climate-science supporters as 'libs'. The Democratic Party is at least willing to pass (without a single Republican vote) the somewhat-cynically named "Inflation Reduction Act" of 2022, which flawed though it may be, is the most significant climate legislation in 35 years. For US voters, that makes electing Democratic candidates the correct course, at least until some Republican candidate is willing to publicly defy their party. Supporters of alternative political courses are obliged to explain how they'll acquire the power to implement their proposals.
I clicked on your hot model paper and saw that Kate Marvel was a coauthor. The name sounded familiar and then I put two and two together and recognized the name from some recent interviews by David Wallace Wells at NYT, e.g.
https://www.nytimes.com/interactive/2022/10/26/magazine/climate-change-warming-world.html
https://www.nytimes.com/2023/09/05/opinion/ezra-klein-podcast-kate-marvel.html . Very cool.
I guess my take away is that there is still confidence in the models and we shouldn't totally be freaking out.
Kate Marvel is indeed great and, like Zeke, an excellent communicator on the science and modelling of climate change. She has a TED talk from 6 years ago, but I really like this interview on TVO. It’s a great primer on climate change with clear explanation of key concepts like forcings, feedbacks, and tipping points. https://youtu.be/kZNAlEPMrOY
Kate is awesome, and is leading our chapter in the upcoming US 5th National Climate Assessment. Its been a lot of fun working closely together on that over the past few years.
RE: Natural gas as a transition fuel.
FYI, I found your BTI article from 2019 and yaleclimateconnections article from 2016 on natural gas so I think I have the answers/information was I looking for - a quick aside the figures for GWP are very slightly different in the two which I did not understand. BTW, did you see that McKibben had an article about LNG in the New Yorker yesterday, https://www.newyorker.com/news/daily-comment/a-smoking-gun-for-bidens-big-climate-decision ?
Would it be correct to say that the models are broadly correct on a global average basis? Most of the outliers we have seen recently are more local (like the North Atlantic) and those outliers really get averaged out when looking at the entire globe.
Has this blog discussed the 2019 Perspective by Palmer and Stevens in PNAS, titled "The scientific challenge of understanding and estimating climate change" (https://www.pnas.org/doi/pdf/10.1073/pnas.1906691116)? From the introduction:
"As climate scientists, we are rightfully proud of, and eager to talk about, our contribution to settling important and long-standing scientific questions of great societal relevance. What we find more difficult to talk about is our deep dissatisfaction with the ability of our models to inform society about the pace of warming, how this warming plays out regionally, and what it implies for the likelihood of surprises. In our view, the political situation, whereby some influential people and institutions misrepresent doubt about anything to insinuate doubt about everything, certainly contributes to a reluctance to be too openly critical of our models. Unfortunately, circling the wagons leads to false impressions about the source of our confidence and about our ability to meet the scientific challenges posed by a world that we know is warming globally."
I take that to mean "don't overlook the shortcomings of current models, but consider your audience."
Zeke, as you point out, for the CMIP6 models they use historical data up to 2015.
As a result, your post-2008 graphs are a joke, half historical, half future. You are NOT looking at how well the models do at predicting the future.
And if you look at that, at how they predict the post-2014 trends, the models are doing HORRIBLY, running almost twice as warm as the real world. So you've clearly cherry-picked your starting point.
Next, I do love the part where you say:
===
"CMIP6 contains a subset of models that are running quite hot (>5C climate sensitivity per doubling CO2) that generally do a poor job of representing historical global surface temperatures.
For this reason, the most recent IPCC report created Assessed Warming Projections that weight the CMIP6 ensemble by its performance in matching historical temperatures, and tend to show future warming more in-line with the prior generation of climate models (CMIP5)."
===
Gosh, Zeke, so you're telling us that if you throw away all the models that do a very poor job of modeling, the rest of the models do a wonderful job of modeling?
Really? That passes for a scientific argument on your planet?
Finally, you've put up the historical hindcasts of the models as if they meant something … but you're totally ignoring a curious fact about these '100% physics based' models, a fact pointed out by Dr. Jeffrey Kiehl in 2007 and resolutely ignored by climate scientists since then.
These model have radically different values for climate sensitivity, varying by a factor of four, from about 1.5 °C/2xCO2 to 6°C/2xCO2 … and despite that, they can all do a pretty dang good job of hindcasting the past.
Say what???
Simply put, that would not be possible if these models were actually "physics-based" as the modaholics claim … but they're not. They are a collection of kludges and tuned parameters that are carefully adjusted, rewritten, and put under pressure until they can hindcast the past.
But as the post 2015 data above shows, they are really bad at predicting the future.
That should come a no surprise. In the US, stock brokerages are required to put a disclaimer on their ads saying something like "Past performance is no guarantee of future success" … climate models desperately need the same warming.
In short, this might make a great high-school paper about models. But it ignores the real failings of the models, and just spreads peanut butter over the glaring gaps in the logic, the use of egregious cherry picking, the discarding of models that don't fit the party line, and the clear lack of any actual physics basis for the models.
TL;DR Version?
Would not recommend.
My best to all, including Zeke. He's a genius meteorologist, but unfortunately, also a craven apologist for the Tinkertoy™ models.
w.
PS—my post on Dr. Kiehl's findings is:
https://wattsupwiththat.com/2013/10/01/dr-kiehls-paradox/
And my post on how the model temperature outputs can be accurately emulated by a very simple lagged, resized version of the forcings is:
http://wattsupwiththat.com/2011/05/14/life-is-like-a-black-box-of-chocolates/
I am left curious why CMIP6 performs significantly worse CMIP5. We know sensitivity is not 5C, so why are hot-running, poor postdicting models even included in the ensemble? I would think it better to focus on the top 5 or so most accurate models and vary initiation parameters to fill out the stocastic grey envelope. Over time modeling should get better not worse!
Well, the traditional approach has been model democracy. But as we argue in our Nature piece, the issues with CMIP6 (and the choice of the AR6 to develop its own weighted ensemble for Assessed Warming Projections) show that approach is outdated.
Nitpick re “we would expect roughly one in 20 months to be above the 95th percentile range if models are accurately representing real-world variability.” Shouldn’t that read “… outside the 95th percentile range …”?
On a warming planet I guess it’s more likely to be above than below, but still.
I've updated it to be clearer and just say we expect one in 20 months to be above the 95th percentile (since I'm actually showing the 90th percentile range, from p5 to p95).
Would you please explain "w.r.t. a" indicated at vertical axis in the first 3 figures: warming trend... ?
The y-axis label should be read as "°C with respect to a 1900-2000 baseline". The baseline is at 0°C of global mean surface temperature rise.
[Edit: the Y-intercept isn't always the 1900-2000 baseline. I'm glad I could correct myself before somebody else did! MA]
Thank you for the answer.
For your 2d point, I read some discussions about "what if" the baseline is not 1900-2000...
You're welcome. But the baseline of Zeke's graphs is chosen to quantify changes in GMST over the period of interest. Choosing a different baseline affects the total amount of change, but not the rate of change during that period. Does that help?
Yes. Thank you. I am very interested by the present question of, if there is an "acceleration" of the temperature increase, does the model of the paper will be able to match the observations. The conclusions is "yes" for the moment in the paper. Will the model remain consistent as it is said until now !
Hey Zeke, you stated a while back that you did not support the conclusions in Hansen's paper, Global Warming In The Pipeline, but you then went on the New York Times and stated that warming was celebrating here: https://nytimes.com/2023/10/13/opinion/climate-change-excessive-heat-2023.html
Could you clarify your stance? Thanks
Also, what are your thoughts on the documentary by ABC news “Earth 2100”? It depicts a rather scary future where we do indeed collapse by then, but with believable reasons. Take a look, it’s both worrying and interesting!
Zeke,
I Google your name occasionally to catch up with your Twitter/X posts, (I refuse to subscribe to X.) Nice summary on global emissions today at Carbon Brief, https://www.carbonbrief.org/analysis-growth-of-chinese-fossil-co2-emissions-drives-new-global-record-in-2023/ . We will have to wait to see if emissions peak next year.
There is so much misinformation out there and even good people like Andy Revkin get taken in by people like Roger Pielke Jr., https://substack.com/@revkin/note/c-44555537 . My biggest problem with the 'Low Hanging Fruit' post by Roger is that Roger claims that if we replace 5% of the worst coal plants would with nuclear we will decrease emissions by 9 Gt per year. That is so wrong on so many levels especially since global coal power generation emissions are about 10.5 Gt / year. His analysis is predicated on the erroneous paper by Grant et al. I estimate that at best getting rid of the worst 5% would maybe save 8% of the emissions caused by coal generation, .84 Gt / year - Ref. https://www.nature.com/articles/s41893-019-0221-6 .
I refuse to subscribe to THB just to call him on it.
Any chance you or Andrew care to take that on?
I changed my mind, paid for a month subscription at THB and posted my reply correcting RPJ’s analysis of CO2 abatement costs between nuclear and the IRA. It was well received by Roger and he was appreciative. He wants to write a paper together. I’m not interested in doing that but maybe I did some good in a very small way.
Viewing Roger’s blog is free if you are interested in seeing the exchange, https://rogerpielkejr.substack.com/p/low-hanging-fruit/comments . My comment should be one of the most recent.
My abatement costs are still way too high compared to what I see elsewhere for abatement costs of CO2. I would like to understand how traditional abatement costs are calculated.
Thanks for doing that.