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The claim of reduced uncertainty for equilibrium climate sensitivity is premature

Filed under: — rasmus @ 21 January 2018

A recent story in the Guardian claims that new calculations reduce the uncertainty associated with a global warming:

A revised calculation of how greenhouse gases drive up the planet’s temperature reduces the range of possible end-of-century outcomes by more than half, …

It was based on a study recently published in Nature (Cox et al. 2018), however, I think its conclusions are premature.

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References

  1. P.M. Cox, C. Huntingford, and M.S. Williamson, "Emergent constraint on equilibrium climate sensitivity from global temperature variability", Nature, vol. 553, pp. 319-322, 2018. http://dx.doi.org/10.1038/nature25450

Fake news, hacked mail, alternative facts – that’s old hat for climate scientists

Distortion? False information? Conspiracy theories? Hacked email? Climate scientists have known all this for decades. What can be learned from their rich experience with climate propaganda.

The world is slowly waking up. “Post-truth” was declared the word of the year 2016 by the Oxford Dictionaries. Finally, people start to widely appreciate how dangerous the epidemic of fake news is for democracy.

Stir up hate, destroy discourse, make insane claims until no one can distinguish the most bizarre absurdity from the truth any more.

Thus the Austrian author Robert Misik aptly describes the strategy of right-wing populists.

Some call it “alternative facts”. (Those are the convenient alternative to true facts.) Let’s simply call it propaganda. More »

Blizzard Jonas and the slowdown of the Gulf Stream System

Filed under: — stefan @ 24 January 2016

Blizzard Jonas on the US east coast has just shattered snowfall records. Both weather forecasters and climate experts have linked the high snowfall amounts to the exceptionally warm sea surface temperatures off the east coast. In this post I will examine a related question: why are sea surface temperatures so high there, as shown in the snapshot from Climate Reanalyzer below?

 

GFS-025deg_NH-SAT1_SST_anom_24_Jan_2016

I will argue that this warmth (as well as the cold blob in the subpolar Atlantic) is partly due to a slowdown of the Atlantic Meridional Overturning Circulation (AMOC), sometimes referred to as the Gulf Stream System, in response to global warming. There are two points to this argument:

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Noise on the Telegraph

Filed under: — rasmus @ 11 February 2015

I was surprised by the shrill headlines from a British newspaper with the old fashioned name the Telegraph: “The fiddling with temperature data is the biggest science scandal ever”. So what is this all about?

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Storm surge: Hurricane Sandy

Filed under: — group @ 29 October 2014

On the second anniversary of Superstorm Sandy making landfall, we are running an extract from a new book by Adam Sobel “Storm Surge: Hurricane Sandy, Our Changing Climate, and Extreme Weather of the Past and Future”. It’s a great read covering the meteorology of the event, the preparation, the response and the implications for the future.

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Labels for climate data

Filed under: — rasmus @ 24 April 2014

metadata-fig “These results are quite strange”, my colleague told me. He analysed some of the recent climate model results from an experiment known by the cryptic name ‘CMIP5‘. It turned out that the results were ok, but we had made an error when reading and processing the model output. The particular climate model that initially gave the strange results had used a different calendar set-up to the previous models we had examined.

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A new European report on climate extremes is out

A new report on extreme climate events in Europe is just published: ‘Extreme Weather Events in Europe: preparing for climate change adaptation‘. It was launched in Oslo on October 24th by the Norwegian Academy of Science and Letters, and the report is now available online.

Front cover of 'Extreme Weather Events in Europe: preparing for climate change adaptation'

Front cover of ‘Extreme Weather Events in Europe:
preparing for climate change adaptation’

What’s new? The new report provides information that is more specific to Europe than the SREX report from the Intergovernmental Panel on Climate Change (IPCC), and incorporate phenomena that have not been widely covered.

It provides some compelling information drawn from the insurance industry, and indeed, a representative from Munich Re participated in writing this report. There is also material on convective storms, hail, lightening, and cold snaps, and the report provides a background on extreme value statistics, risk analysis, impacts, and adaptation.

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A new experiment with science publication

Filed under: — rasmus @ 28 June 2013

A while ago, I received a request to publish a paper on a post that I had written here on RealClimate, exposing the flaws in the analysis of Humlum et al., (2011).

Instead of writing a comment to one paper, however, I thought it might be useful to collect a sample of papers that I found unconvincing (usual suspects), and that have had a fairly high public profile.

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References

  1. O. Humlum, J. Solheim, and K. Stordahl, "Identifying natural contributions to late Holocene climate change", Global and Planetary Change, vol. 79, pp. 145-156, 2011. http://dx.doi.org/10.1016/j.gloplacha.2011.09.005

The answer is blowing in the wind: The warming went into the deep end

There has been an unusual surge of interest in the climate sensitivity based on the last decade’s worth of temperature measurements, and a lengthy story in the Economist tries to argue that the climate sensitivity may be lower than previously estimated. I think its conclusion is somewhat misguided because it missed some important pieces of information (also see skepticalscience’s take on this story here).

The ocean heat content and the global mean sea level height have marched on.

While the Economist referred to some unpublished work, it missed a new paper by Balmaseda et al. (2013) which provides a more in-depth insight. Balmaseda et al suggest that the recent years may not have much effect on the climate sensitivity after all, and according to their analysis, it is the winds blowing over the oceans that may be responsible for the ‘slow-down’ presented in the Economist.

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References

  1. M.A. Balmaseda, K.E. Trenberth, and E. Källén, "Distinctive climate signals in reanalysis of global ocean heat content", Geophysical Research Letters, vol. 40, pp. 1754-1759, 2013. http://dx.doi.org/10.1002/grl.50382

Ice hockey

Eric Steig

It is well known that ice shelves on the Antarctic Peninsula have collapsed on several occasions in the last couple of decades, that ice shelves in West Antarctica are thinning rapidly, and that the large outlet glaciers that drain the West Antarctic ice sheet (WAIS) are accelerating. The rapid drainage of the WAIS into the ocean is a major contributor to sea level rise (around 10% of the total, at the moment).

All of these observations match the response, predicted in the late 1970s by glaciologist John Mercer, of the Antarctic to anthropogenic global warming. As such, they are frequently taken as harbingers of greater future sea level rise to come. Are they?

Two papers published this week in Nature Geoscience provide new information that helps to address this question. One of the studies (led by me) says “probably”, while another (Abram et al.) gives a more definitive “yes”. More »