May 28, 2023·edited May 28, 2023Liked by Andrew Dessler
Thanks to both of you for this explanation. My problem is that I feel that these caveats are not highlighted enough in the paper. These should be stated very clearly upfront otherwise people that are not experts will become alarmed and draw the wrong conclusions, e.g. that Jim has found some missing physics that everyone else has missed and that we are doomed to 10C.
I believe that Hansen is *also* saying that IPCC assumptions about warming/ZEC are wrong:
"Section 3 (Climate Response Time) explores the fast-feedback response time of Earth’s temperature and energy imbalance to an imposed forcing, concluding that cloud feedbacks buffer heat uptake by the ocean, thus increasing warming in the pipeline and making Earth’s energy imbalance an underestimate of the forcing reduction required to stabilize climate."
Greetings from Auckland. I apologise for not being able to support you financially - I gave all my money to my children (the eldest 50) to buy houses to live in - but I did buy "Introduction to Modern Climate Change" prior!
My question is: If we stop emitting CO2, do the oceans start outgassing CO2? Since the oceans have been absorbing say a third of our CO2, one might think "yes". I guess it depends on how quickly the CO2 becomes sediment/how acidified they remain?
Yours is a great "hobby" - you CAN give up your day job ... hahaha :)
First to say I appreciate Zeke Hausfather thoughtful comments. Jim Hansen has a track record of very good work without ever trying to get it published in top journals (which due to space limitations would not never publish such analysis.)
Regarding some comments here on the question, raised by the author of this article, whether GHG levels will necessarily decline at some point in the future - i.e. at the latest once we run out of fossil fuels and CO2 emissions will stop: there is another one of Hansen's papers published 10 years ago that estimated the implications of burning all available fossil fuels, using a similar method based on paleo-climate analogues and minimal modeling:
Hansen J, Sato M, Russell G, Kharecha P. 2013 Climate sensitivity, sea level and atmospheric carbon dioxide. Phil Trans R Soc A 371: 20120294. http://dx.doi.org/10.1098/rsta.2012.0294
He estimated a resulting forcing of 9 W/m^2 and an (actual) warming of 16C, 30C at the poles and 20C over land areas. That would make much of the planet uninhabitable:
"Such temperatures would eliminate grain production in almost all agricultural regions in the world. Increased stratospheric water vapour would diminish the stratospheric ozone layer. [...] A warming of [only] 10–12C would put most of today’s world population in regions with wet a [deadly] bulb temperature above 35C. [...] there are more than enough fossil fuels to cause a forcing of 9W/m2 sustained over centuries."
What about the accelerated warming the preprint talks about - is this a new suggestion? I understand that sulfate aerosols mask warming, so a reduction of aerosols alone would increase temperature - but are they suggesting the effect is greater than previously believed?
You write, "We will definitely stop burning fossil fuels in somewhere between a few decades to a few centuries."
What makes you think that? Do you think that as a species, we will forget how to build internal combustion engines? Perhaps you're assuming some political miracle? What would drive that massive reversal?
Thanks to both of you for this explanation. My problem is that I feel that these caveats are not highlighted enough in the paper. These should be stated very clearly upfront otherwise people that are not experts will become alarmed and draw the wrong conclusions, e.g. that Jim has found some missing physics that everyone else has missed and that we are doomed to 10C.
https://insideclimatenews.org/news/26052023/james-hansen-climate-change-2-degrees-2050/
I believe that Hansen is *also* saying that IPCC assumptions about warming/ZEC are wrong:
"Section 3 (Climate Response Time) explores the fast-feedback response time of Earth’s temperature and energy imbalance to an imposed forcing, concluding that cloud feedbacks buffer heat uptake by the ocean, thus increasing warming in the pipeline and making Earth’s energy imbalance an underestimate of the forcing reduction required to stabilize climate."
Greetings from Auckland. I apologise for not being able to support you financially - I gave all my money to my children (the eldest 50) to buy houses to live in - but I did buy "Introduction to Modern Climate Change" prior!
My question is: If we stop emitting CO2, do the oceans start outgassing CO2? Since the oceans have been absorbing say a third of our CO2, one might think "yes". I guess it depends on how quickly the CO2 becomes sediment/how acidified they remain?
Yours is a great "hobby" - you CAN give up your day job ... hahaha :)
First to say I appreciate Zeke Hausfather thoughtful comments. Jim Hansen has a track record of very good work without ever trying to get it published in top journals (which due to space limitations would not never publish such analysis.)
Regarding some comments here on the question, raised by the author of this article, whether GHG levels will necessarily decline at some point in the future - i.e. at the latest once we run out of fossil fuels and CO2 emissions will stop: there is another one of Hansen's papers published 10 years ago that estimated the implications of burning all available fossil fuels, using a similar method based on paleo-climate analogues and minimal modeling:
Hansen J, Sato M, Russell G, Kharecha P. 2013 Climate sensitivity, sea level and atmospheric carbon dioxide. Phil Trans R Soc A 371: 20120294. http://dx.doi.org/10.1098/rsta.2012.0294
He estimated a resulting forcing of 9 W/m^2 and an (actual) warming of 16C, 30C at the poles and 20C over land areas. That would make much of the planet uninhabitable:
"Such temperatures would eliminate grain production in almost all agricultural regions in the world. Increased stratospheric water vapour would diminish the stratospheric ozone layer. [...] A warming of [only] 10–12C would put most of today’s world population in regions with wet a [deadly] bulb temperature above 35C. [...] there are more than enough fossil fuels to cause a forcing of 9W/m2 sustained over centuries."
My additions and omissions in [].
What about the accelerated warming the preprint talks about - is this a new suggestion? I understand that sulfate aerosols mask warming, so a reduction of aerosols alone would increase temperature - but are they suggesting the effect is greater than previously believed?
You write, "We will definitely stop burning fossil fuels in somewhere between a few decades to a few centuries."
What makes you think that? Do you think that as a species, we will forget how to build internal combustion engines? Perhaps you're assuming some political miracle? What would drive that massive reversal?