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Climate Science

Climate Sensitivity: A new assessment

22 Jul 2020 by Gavin

Not small enough to ignore, nor big enough to despair.

There is a new review paper on climate sensitivity published today (Sherwood et al., 2020 (preprint) that is the most thorough and coherent picture of what we can infer about the sensitivity of climate to increasing CO2. The paper is exhaustive (and exhausting – coming in at 166 preprint pages!) and concludes that equilibrium climate sensitivity is likely between 2.3 and 4.5 K, and very likely to be between 2.0 and 5.7 K.

[Read more…] about Climate Sensitivity: A new assessment

References

  1. S.C. Sherwood, M.J. Webb, J.D. Annan, K.C. Armour, P.M. Forster, J.C. Hargreaves, G. Hegerl, S.A. Klein, K.D. Marvel, E.J. Rohling, M. Watanabe, T. Andrews, P. Braconnot, C.S. Bretherton, G.L. Foster, Z. Hausfather, A.S. von der Heydt, R. Knutti, T. Mauritsen, J.R. Norris, C. Proistosescu, M. Rugenstein, G.A. Schmidt, K.B. Tokarska, and M.D. Zelinka, "An Assessment of Earth's Climate Sensitivity Using Multiple Lines of Evidence", Reviews of Geophysics, vol. 58, 2020. http://dx.doi.org/10.1029/2019RG000678

Filed Under: Climate modelling, Climate Science, Instrumental Record, Paleoclimate

Shellenberger’s op-ad

9 Jul 2020 by group

Guest commentary by Michael Tobis

This is a deep dive into the form and substance of Michael Shellenberger’s promotion for his new book “Apocalypse Never”. Shorter version? It should be read as a sales pitch to a certain demographic rather than a genuine apology.

Michael Shellenberger appears to have a talent for self-promotion. His book, provocatively entitled “Apocalypse Never” appears to be garnering considerable attention. What does he mean by that title? Does it mean we should do whatever we can to avoid an apocalypse? Does it mean that no apocalypse is possible in the foreseeable future? For those of us who haven’t yet read the book (now available on Kindle), Shellenberger provides an unusual article (at first posted on Forbes, then at Quillette and the front page of the Australian) which appears less a summary than a sales pitch, an “op-ad” as one Twitter wag put it.

It’s called “On Behalf Of Environmentalists, I Apologize For The Climate Scare”. In short, Shellenberger lands clearly on the naysayer soil. Not much to see, everyone. Cheer up, carry on, these are not the droids you’re looking for.

FEW PEOPLE KNOW THAT THE MOON IS MADE OF CHEESE

In support of this insouciance, Shellenberger offers twelve “facts few people know”. Most of the points are defensible to some extent, and most of them raise interesting topics. A main purpose of this article is to provide references to the relevant discussions. But in going through it, it’s worth keeping an eye on the rhetorical purposes of the items, which appear a bit scattershot, and to the rhetorical purpose of the list, which might appear rather obscure.

Clearly labeling the list “facts that few people know” implies that all these points unambiguously refute common beliefs that are widely. And the “apology for the climate scare” indicates further that these beliefs are widely held by a supposedly misguided community of “climate scared”. A defender of the list, Blair King suggests that “[Shellenberger] identified false talking points used repeatedly by alarmists to misinform the public and move debate away from one that is evidence-based to one driven by fear and misinformation”. That does seem to be a fair reading of the stated intent of the list, but it just doesn’t ring true as a whole.

Speaking as a verteran “climate scared” person, the items don’t seem especially familiar. It’s hard to imagine a conversation like this:“Gosh, climate change is an even bigger threat to species than habitat loss.”“I know, and the land area used for producing meat is increasing!”As Gerardo Ceballos said:

This is not a scientific paper. It is intended, I guess, to be an article for the general public. Unfortunately, it is neither. It does not have a logical structure that allows the reader to understand what he would like to address, aside from a very general and misleading idea that environmentalists and climate scientists have been alarmist in relation to climate change. He lists a series of eclectic environmental problems like the Sixth Mass Extinction, green energy, and climate disruption. And without any data nor any proof, he discredits the idea that those are human-caused, severe environmental problems. He just mentions loose ideas about why he is right and the rest of the scientists, environmentalists, and general public are wrong.

What causes the strange incoherence of these “facts few people know”? At the end of this review I’ll propose an answer. Meanwhile, I will consider several questions regarding each item:

  • VALIDITY Is the claim unambiguously true? Unambiguously false? Disputed?
  • RELEVANCE TO CLIMATE Is the claim directly relevant to climate concern/”climate scare” or is it more of interest to tangentially related environmental issues?
  • SALIENCE Is the contrary of the claim widely believed by environmental activists? Does widespread belief in the claim contribute materially to an excess of climate concern?
  • IMPLICATION What is the rhetorical purpose of the question?
  • REALITY To what extent is the rhetorical purpose justified?
[Read more…] about Shellenberger’s op-ad

Filed Under: Climate impacts, Climate Science, Sea level rise

Unforced Variations: July 2020

1 Jul 2020 by group

This month’s open thread for climate science topics.

Filed Under: Climate Science, Open thread

Sensitive but unclassified: Part II

13 Jun 2020 by Gavin

The discussion and analysis of the latest round of climate models continues – but not always sensibly.

[Read more…] about Sensitive but unclassified: Part II

Filed Under: Climate modelling, Climate Science

‘2040’

3 Jun 2020 by rasmus

After an absurd period with a real-life gloomy corona pandemic, lock-down and unrest, it was quite refreshing to see visions for a sustainable future in a new documentary ‘2040‘ (link to trailer). Its message, through the voice of Damon Gameau, is about hope and is based on rational thinking.


The video takes us to twenty years fast-forward to an imagined future. It makes good use of effects that communicate. For instance, Damon Gameau speaks with children about green and sustainable solutions and then makes the time travel to show what such a future may look like when climate change has stopped.


The documentary also makes use of some cool effects to demonstrate how things work. But it is mostly about a positive message on solutions rather than emphasising climate science and harmful consequences of climate change.


There is an interesting timing with the release of ‘2040’, and hopefully it will contribute to discussions about new solutions and how we can make use of both technology and new behaviour to improve our lives and the health of the planet. This is something that is already being discussed in Europe.


I thought the documentary made some interesting points about energy production, how to make agriculture more sustainable through mixed crops and good soil health, and how to use ocean resources. Another important point is the importance of empowering girls and women. However, I’m not in the position to say how successful the suggested solutions would be. I guess we may know answers in 2040.

Filed Under: Climate Science

Unforced variations: Jun 2020

2 Jun 2020 by group

This month’s open thread on climate science issues.

Filed Under: Climate Science, Open thread

Unforced variations: May 2020

1 May 2020 by group

This month’s climate science open thread.

Filed Under: Climate Science, Open thread

Nenana Ice Classic 2020

27 Apr 2020 by Gavin

Readers may recall my interest in phenological indicators of climate change, and ones on which $300K rest are a particular favorite. The Nenana Ice Classic is an annual tradition since 1917, and provides a interesting glimpse into climate change in Alaska.

This year’s break-up of ice has just happened (unofficially, Apr 27, 12:56pm AKST), and, like in years past, it’s time to assess what the trends are. Last year was a record early break-up (on April 14th), and while this year was not as warm, it is still earlier than the linear trend (of ~8 days per century) would have predicted, and was still in the top 20 earliest break-ups.

Nenana Ice Classic ice break up dates

A little side bet I have going is whether any of the contrarians mention this. They were all very excited in 2013 when the record for the latest break-up was set, but unsurprisingly not at all interested in any subsequent years (with one exception in 2018). This year, they could try something like ‘it’s cooling because the break up was two weeks later than last year (a record hot year)’, but that would be lame, even by their standards.

Filed Under: Arctic and Antarctic, Climate Science, Instrumental Record

Regional climate modeling and some common omissions

17 Apr 2020 by rasmus

There is a growing need for local climate information in order to update our understanding of risks connected to the changing weather and prepare for new challenges. This need has been an important motivation behind the World Meteorological Organisation’s (WMO) Global Framework for Climate Services (GFCS).

There has also been a lot of work carried out to meet these needs over time, but I’m not convinced that people always get the whole story.  

[Read more…] about Regional climate modeling and some common omissions

Filed Under: Climate Science

A problem with YouTube

7 Apr 2020 by rasmus

The American Geophysical Union (AGU) started to stream sessions at their annual meeting in San Francisco a few years ago. This kind of participation over the Internet is a nice alternative since many scholars are unable to attend the AGU meetings due to distance, time constraints, time difference and cost.

  [Read more…] about A problem with YouTube

Filed Under: Climate Science

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