Guest essay by Eric Worrall
Even worse than we thought ™ – global warming estimates have been raised, just in time for next year’s COP26 conference. But one of high end CMIP6 models, CESM2 (highlighted above), has already been invalidated by a paleo study.
Just how hot will it get this century? Latest climate models suggest it could be worse than we thought
Michael Grose Climate Projections Scientist, CSIRO
Julie Arblaster Associate Professor, Monash University
May 18, 2020 5.58am AESTClimate scientists use mathematical models to project the Earth’s future under a warming world, but a group of the latest modelshave included unexpectedly high values for a measure called “climate sensitivity”.
Climate sensitivity refers to the relationship between changes in carbon dioxide in the atmosphere and warming.
The high values are an unwelcome surprise. If they’re right, it means a hotter future than previously expected – warming of up to 7℃ for Australia by 2100 if emissions continue to rise unabated.
Our recent study analyses these climate models (named CMIP6), which were released at the end of last year, and what insights they give for Australia.
These models contain the latest improvements and innovations from some of the world’s leading climate modelling institutes, and will feed into the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report in 2021.
But the new climate sensitivity values raise the question of whether previous climate modelling has underestimated potential climate change and its effects, or whether the new models are overdoing things.
If the high estimate is right, this would require the world to make greater and more urgent emission cuts to meet any given warming target.
…
Read more: https://theconversation.com/just-how-hot-will-it-get-this-century-latest-climate-models-suggest-it-could-be-worse-than-we-thought-137281
A few weeks ago WUWT reported a study which determined CESM2 predictions are incompatible with the fossil record, because CESM2 incorrectly hindcasts temperatures which would have created lifeless tropical deserts during the Early Eocene, a period of high atmospheric CO2 and abundant tropical life.
“Some of the newest models used to make future predictions may be too sensitive to increases in atmospheric carbon dioxide and thus predict too much warming,” said U-M’s Chris Poulsen, a professor in the U-M Department of Earth and Environmental Sciences and one of the study’s three authors. – source Science Daily
CESM2 is a component of high end CMIP6 projections (see the diagram at the top of the page).
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If it’s worse than we thought, that means what they thought before was wrong. If they were wrong before, why should we believe they’ve got it right this time? (particularly as this isn’t the first “worse they we thought” ie “we were wrong before” moment, nor the second, nor the third, etc. After being wrong countless times, now we’re supposed to believe they finally got it right? pull the other one, it has bells on.
I am wondering as a layman. I hear the word trapped a lot. Is the CO2 being trapped or is it just taking longer to escape because of thicker CO2?
The way I understand it is that the light waves that heat the earth bounce off the earth and are lost into space, but with the rising CO2 it gets trapped so the temperature increases.
Is it possible that at first the light is reflected back from the CO2 but is able to try again to escape, I believe we are losing this light into space now. If the light can again try to escape is this variable added into the models?
The last person to reply on this post was four days ago, so no one will likely see your question. I’m a moderator. That’s why I saw it.