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State of Antarctica: red or blue? Lo stato dell’Antartide: più caldo o più freddo?

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A couple of us (Eric and Mike) are co-authors on a paper coming out in Nature this week (Jan. 22, 09). We have already seen misleading interpretations of our results in the popular press and the blogosphere, and so we thought we would nip such speculation in the bud.

The paper shows that Antarctica has been warming for the last 50 years, and that it has been warming especially in West Antarctica (see the figure). The results are based on a statistical blending of satellite data and temperature data from weather stations. The results don’t depend on the statistics alone. They are backed up by independent data from automatic weather stations, as shown in our paper as well as in updated work by Bromwich, Monaghan and others (see their AGU abstract, here), whose earlier work in JGR was taken as contradicting ours. There is also a paper in press in Climate Dynamics (Goosse et al.) that uses a GCM with data assimilation (and without the satellite data we use) and gets the same result. Furthermore, speculation that our results somehow simply reflect changes in the near-surface inversion is ruled out by completely independent results showing that significant warming in West Antarctica extends well into the troposphere. And finally, our results have already been validated by borehole thermometery — a completely independent method — at at least one site in West Antarctica (Barrett et al. report the same rate of warming as we do, but going back to 1930 rather than 1957; see the paper in press in GRL).

Una traduzione in italiano è disponibile qui.
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CNN is spun right round, baby, right round

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With the axing of the CNN Science News team, most science stories at CNN are now being given to general assignment reporters who don’t necessarily have the background to know when they are being taken for a ride. On the Lou Dobbs show (an evening news program on cable for those of you not in the US), the last few weeks have brought a series of embarrassing non-stories on ‘global cooling’ based it seems on a few cold snaps this winter, the fact that we are at a solar minimum and a regurgitation of 1970s vintage interpretations of Milankovitch theory (via Pravda of all places!). Combine that with a few hysterical (in both senses) non-scientists as talking heads and you end up with a repeat of the nonsensical ‘Cooling world’ media stories that were misleading in the 1970s and are just as misleading now.

Exhibit A. Last night’s (13 Jan 2009) transcript (annotations in italics).
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Communicating the Science of Climate Change

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It is perhaps self-evident that those of us here at RealClimate have a keen interest in the topic of science communication. A number of us have written books aimed at communicating the science to the lay public, and have participated in forums devoted to the topic of science communication (see e.g. here, here, and here). We have often written here about the challenges of communicating science to the public in the modern media environment (see e.g. here, here, and here).

It is naturally our pleasure, in this vein, to bring to the attention of our readers a masterful new book on this topic by veteran environmental journalist and journalism educator Bud Ward. The book, entitled Communicating on Climate Change: An Essential Resource for Journalists, Scientists, and Educators, details the lessons learned in a series of Metcalf Institute workshops held over the past few years, funded by the National Science Foundation, and co-organized by Ward and AMS senior science and communications fellow Tony Socci. These workshops have collectively brought together numerous leading members of the environmental journalism and climate science communities in an effort to develop recommendations that might help bridge the cultural divide between these two communities that sometimes impedes accurate and effective science communication.

I had the privilege of participating in a couple of the workshops, including the inaugural workshop in Rhode Island in November 2003. The discussions emerging from these workshops were, at least in part, the inspiration behind “RealClimate”. The workshops formed the foundation for this new book, which is an appropriate resource for scientists, journalists, editors, and others interested in science communication and popularization. In addition to instructive chapters such as “Science for Journalism“, “Journalism for Scientists” and “What Institutions Can Do“, the book is interspersed with a number of insightful essays by leading scientists (e.g. “Mediarology–The Role of Climate Scientists in Debunking Climate Change Myths” by Stephen Schneider) and environmental journalists (e.g. “Hot Words” by Andy Revkin). We hope this book will serve as a standard reference for how to effectively communicate the science of climate change.

The Younger Dryas comet-impact hypothesis: gem of an idea or fool’s gold?

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There was a paper in Science last week that has gotten quite a bit of press. It reports further evidence in support of the idea that the Younger Dryas — a distinct period towards the end of the last ice age when the deglaciation in the Northern Hemisphere was interrupted for a period of about 1300 years — was caused by a barrage of comets hitting North America.

When the first papers on this came out last year, we expressed skepticism. We remain skeptical and our reasons remain unchanged. But we think it is worth saying a bit more on this, because the reporting on this issue has largely ignored just how big an idea this is, and therefore how much more work would need to be done before it could be taken very seriously.
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FAQ on climate models: Part II

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This is a continuation of a previous post including interesting questions from the comments.

More Questions

  • What are parameterisations?

    Some physics in the real world, that is necessary for a climate model to work, is only known empirically. Or perhaps the theory only really applies at scales much smaller than the model grid size. This physics needs to be ‘parameterised’ i.e. a formulation is used that captures the phenomenology of the process and its sensitivity to change but without going into all of the very small scale details. These parameterisations are approximations to the phenomena that we wish to model, but which work at the scales the models actually resolve. A simple example is the radiation code – instead of using a line-by-line code which would resolve the absorption at over 10,000 individual wavelengths, a GCM generally uses a broad-band approximation (with 30 to 50 bands) which gives very close to the same results as a full calculation. Another example is the formula for the evaporation from the ocean as a function of the large-scale humidity, temperature and wind-speed. This is really a highly turbulent phenomena, but there are good approximations that give the net evaporation as a function of the large scale (‘bulk’) conditions. In some parameterisations, the functional form is reasonably well known, but the values of specific coefficients might not be. In these cases, the parameterisations are ‘tuned’ to reproduce the observed processes as much as possible.

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Environmental reporters ought to be more responsible too

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At RealClimate, we have more than once been accused of being imbalanced — criticizing those who would deny the basic science of climate change, while leaving inflammatory statements by what might be called the “environmentalist side” without comment. It’s not an entirely a fair criticism, because there is a world of difference between the willful obfuscation of science and the naive exaggeration of it. There are however plenty of silly, and sometimes outrageous, claims made – see e.g. the Telegraph on Jan. 3rd — and we probably ought to do a better job of calling these out, particularly when they show up in prominent places. So to inaugurate the New Year, I humbly offer a rant about a minor but illustrative example that I happened to notice because there was a link to it on Nature Reports Climate Change.

The subject of the linked article, in the British online newspaper The Independent, is the decline of various bird and butterfly species in England. The article, entitled Changing climate devastates UK species, reports that “insects in particular, and creatures that feed on insects…were sharply reduced in numbers” due to a “cold late spring, a wet summer, with few sunny days, and the long dry autumn….” Now I have no reason to doubt the accuracy of the claim that 2008 was a hard year for UK insects and insectivores. But this is weather we’re talking about, not climate. And while it is true that at least one prominent study shows that there has been an overall increase in rainfall in the latitude band that includes the UK, and that climate models reproduce this trend (see e.g. the Zhang et al. article in Nature, in 2007), one cannot, as we are fond of pointing out, attribute a single, or even several individual extreme weather events to “climate change”.

Indeed, Peter Stott, a co-author on the Zhang et al. study noted, in reference to 2007 (the wettest summer on record in the UK) that “This latest study cannot make the link between climate change and what we have experienced so far this summer.” Moreover, most projections actually suggest drier summers in the UK in the future, though with increased convection (so less total precipitation, but bigger rainstorms).

Another thing that bugs me about the Independent article is the suggestion that climate is becoming “more unpredictable”. I suspect what is meant here is that we used to know what a mean season and normal variations were, and now we don’t. That’s valid, since the baseline climate is changing. But saying it this way — that “climate is becoming more unpredictable” is misleading. In fact, climate may, if anything, become more predictable as anthropogenic forcing becomes even more dominant (as greenhouse gas concentrations increase), relative to natural forcing and variability. And what is definitely not the case — but might be inferred from the article — is that weather is becoming more unpredictable. Weather prediction is based on observations just a few days in advance — climate and climate trends have nothing to do with it.

The point here is not that we shouldn’t be concerned about the fate of insects and birds in the UK (that would be the kind of conclusion that only the most willfully ignorant would draw.) They have been in decline for a long time (mostly due to land use change and pesticides) and there is little doubt that climate change will continue to add insult to injury. But it is simply wrong to confuse a year or even two years of unfavorable weather with a change in climate, and it is irresponsible to headline an article that is really about weather with the provocative juxtaposition of “climate” and “devastates”. Doing so gives the average reader the sense that their personal observations about “weird weather patterns” or fewer sightings of Parus caeruleus represent definitive manifestations of climate change. The fact is, climate changes are — so far — small enough in most places, relative to the natural variability, that one’s personal experience is a very poor guide to what is happening over the long term (observations of sea ice changes by those that live in the high Arctic notwithstanding).

2008 Year in review

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Way back at the end of 2006, we did a review of the year’s climate science discussion. It’s that time of year again and so we’ve decided to give it another go. Feel free to suggest your own categories and winners…

Most clueless US politician talking about climate change (with the exception of Senator Inhofe who’d always win):
Sarah Palin:

Well, we’re the only Arctic state, of course, Alaska. So we feel the impacts more than any other state, up there with the changes in climates. And certainly, it is apparent. We have erosion issues. And we have melting sea ice, of course. [….] You know there are – there are man’s activities that can be contributed to the issues that we’re dealing with now, these impacts. I’m not going to solely blame all of man’s activities on changes in climate.

Most puzzling finding from 2006 that has yet to be convincingly replicated:
Methane from plants

Most reckless extrapolation of short term trends:
Michael “All global warming has been erased” Asher (Daily Tech)

This year’s most (unsurprisingly) abused study:
Keenlyside et al. initialised climate forecasts (and no, they didn’t take our bet).

Climate scientist with biggest disconnect between his peer-reviewed papers and his online discussions:
Roy Spencer

Most worn out contrarian cliche:
The “Gore Effect”. This combines the irrelevant confusion of climate with weather and the slightly manic obsession with Al Gore over the actual science. Do please grow up.

Most bizarre new contrarian claim:
Global warming is caused by undersea volcanoes (and pirates!).

The S. Fred Singer award for the most dizzying turn-around of a climate pseudo-skeptic:
Dennis Avery: “Global warming is likely to continue” (2006) , to global warming is “unstoppable” (2006), to “Say Good-Bye To Global Warming And Hello To Global Cooling!” (2008).

Pottiest peer on the contrarian comedy circuit:
Viscount Monckton of Brenchley

Least unexpected observations:
(Joint winners) 2008 near-record minima in Arctic sea ice extent, last decade of record warmth, long term increases in ocean heat content, record increases in CO2 emissions.

Most consistently wrong media outlet:
The Australian (runner-up the UK Daily Telegraph). Both comfortably beating out the perennial favorite, the Wall Street Journal – maybe things have really changed there?

Best actual good news:
The grown-ups being back in charge starting January 20 (compare with this).

Most inaccurate attempted insinuation about RealClimate:
‘The Soros-funded Realclimate.org’ Chris Horner

Most revealing insight into some US coal companies and year’s best self parody:
Frosty the Coalman (video available here)

Most disturbing trend for science journalism:
The axing of dedicated science units at CNN, the Weather Channel and elsewhere. Can Climate Central and blogging journalists take up the slack?

Happy New Year to all of our readers!

2008 temperature summaries and spin

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The great thing about complex data is that one can basically come up with any number of headlines describing it – all of which can be literally true – but that give very different impressions. Thus we are sure that you will soon read that 2008 was warmer than any year in the 20th Century (with the exception of 1998), that is was the coolest year this century (starting from 2001), and that 7 or 8 of the 9 warmest years have occurred since 2000. There will undoubtedly also be a number of claims made that aren’t true; 2008 is not the coolest year this decade (that was 2000), global warming hasn’t ‘stopped’, CO2 continues to be a greenhouse gas, and such variability is indeed predicted by climate models. Today’s post is therefore dedicated to cutting through the hype and looking at the bigger picture.

Una traduzione in italiano è disponibile qui.
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Ozone holes and cosmic rays

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ozone hole sept 2007Browsing through the blogosphere recently, I came across an interesting little story about the scientific method, scientific progress, and un-scientific spin (h/t Hank Roberts). The subject concerns the polar ozone hole in Antarctica and a possible role for cosmic rays in its variability on solar cycle timescales. The proponents of this link are a small research group at the University of Sherbrooke in Canada, who find themselves up against the mainstream stratospheric chemistry community and whose ideas are twisted out of all recognition by the more foolish of the usual suspects.

Una traduzione in italiano è disponibile qui
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