Climate science from climate scientists...
There are two hearings today from the new congress that are of relevance for RealClimate readers:
The House Oversight Committee is having hearings on the possible suppression of climate change science by the administration (streaming from here). Witnesses include Drew Shindell (NASA GISS), Roger Pielke Jr. and R. Piltz. Update: Full hearing video available at C-SPAN.
The Senate EPW Committee is having an open forum for senators to discuss climate change legislation (streaming from here).
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) Halldór Björnsson, William Connolley and Gavin Schmidt
Late last year, the UK Treasury’s Stern Review of the Economics of Climate Change was released to rapturous reception from all sides of the UK political spectrum (i.e. left and right). Since then it has been subject to significant criticism and debate (for a good listing see Rabbett Run). Much of that discussion has revolved around the economic (and ethical) issues associated with ‘discounting’ (how you weight welfare in the future against welfare today) – particularly Nordhaus’s review. We are not qualified to address those issues, and so have not previously commented.
However, as exemplified by interviews on a recent Radio 4 program (including with our own William Connolley), some questions have involved the science that underlies the economics. We will try and address those.
Kerry Emanuel (whose influential scientific work we’ve discussed here previously) has written a particularly lucid and poignant popular article on climate change for the literary forum “Boston Review”. The article is entitled Phaeton’s Reins: The human hand in climate change. We thought it worth passing along.
Guest Commentary from Andy Baker, U. of Birmingham
It doesn’t seem obvious really. Going underground into caves, removing stalagmites and analysing their isotopic composition isn’t the first thing you would do to look for past climate information. But for nearly 40 years, there has been an active, and growing research community that investigates the climate records preserved in these archives. Stalagmites have recently received high profile use in climate reconstructions, for example records from China and Norway have featured in Moberg’s last millennium temperature reconstruction; in a northern hemisphere temperature reconstruction of the last 500 years and even been debated here on RealClimate. So it seems timely to review why on (or even under) earth should research go underground to look at surface climate.
“An Inconvenient Truth,” the Davis Guggenheim documentary on global warming starring Al Gore’s presentation on the subject, provides an accurate, engaging, accessible, thought-provoking and (at times) even humorous introduction to one of the most important scientific issues of our time ( see our review of the movie). In some countries, viewing “An Inconvenient Truth” has actually become a required part of the science curriculum, and with good justification, we think. Given that the DVD is currently selling for $19.99 through Amazon.com, you’d think that the National Science Teachers’ Association ( NSTA) would jump at the chance to quickly get 50,000 free copies quickly into the hands of their members. Yet, when Laurie David, one of the producers of the film, made this offer to NSTA last November, it was summarily turned down on the grounds that the NSTA has a 2001 policy against “product endorsement” (as if Laurie David were trying to shop some new deodorant to high school science teachers). What in the world is going on here?
Before continuing with the history of NSTA’s bizarre decision, let us provide you with the most important information: Up to 50,000 US science teachers can receive a free copy of the DVD by filling out a simple request form here . The deadline for requesting your copy is January 18, so if you want a copy, take a few minutes to put in your request right away.
[Read more…] about Calling All Science Teachers
) () Guest Commentary by Cecilia Bitz, University of Washington
Last month a paper I co-authored received considerable media attention. Headlines read “Experts warn North Pole will be ‘ice free’ by 2040”, “The Big Melt: Loss of Sea Ice Snowballs“, and “Arctic Clear for Summer Sailing by 2040: Models Predict Rapid Decline of Sea Ice”. The story also reached NPR, BBC, CBC, the Discovery channel, and Fox News, among others. Dr. Marika Holland, the first author of the paper, was inundated with media attention. About a dozen journalists contacted me too. I was impressed by the questions they posed — questions that probably reflect what the public most wants to know. However, after giving lengthy interviews, I would read the resulting article and see my explanations boiled down to a few lines. In this essay, I’d like to explain the science in the paper and give my answers to the most often asked questions.
[Read more…] about Arctic Sea Ice decline in the 21st Century
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) () It has now become all too common. Peculiar weather precipitates immediate blame on global warming by some, and equally immediate pronouncements by others (curiously, quite often the National Oceanic and Atmospheric Administration in recent years) that global warming can’t possibly be to blame. The reality, as we’ve often remarked here before, is that absolute statements of neither sort are scientifically defensible. Meteorological anomalies cannot be purely attributed to deterministic factors, let alone any one specific such factor (e.g. either global warming or a hypothetical long-term climate oscillation).
Lets consider the latest such example. In an odd repeat of last year (the ‘groundhog day’ analogy growing ever more appropriate), we find ourselves well into the meteorological Northern Hemisphere winter (Dec-Feb) with little evidence over large parts of the country (most noteably the eastern and central U.S.) that it ever really began. Unsurprisingly, numerous news stories have popped up asking whether global warming might be to blame. Almost as if on cue, representatives from NOAA’s National Weather Service have been dispatched to tell us that the event e.g. “has absolutely nothing to do with global warming”, but instead is entirely due to the impact of the current El Nino event.
[Update 1/9/07: NOAA coincidentally has announced today that 2006 was officially the warmest year on record for the U.S.]
[Update 2/11/08: It got bumped to second place. ]
[Read more…] about El Nino, Global Warming, and Anomalous U.S. Winter Warmth
Gavin Schmidt, Michael Mann, David Archer, Stefan Rahmstorf, William Connolley, and Raymond Bradley
Andy Revkin, who’s one of the best journalists on the climate beat, wrote a curious piece in the NY Times discussing the ‘middle stance’ of the climate debate. It’s nice to see news pieces on climate that aren’t breathless accounts of a new breakthough and that take the time to point out that the vast majority of relevant scientists take climate change extremely seriously. To that extent, the message of this piece was a welcome one. The curious part, however, was the thread running through the piece that this middle ground is only now emerging, and even curiouser, that this middle ground can be characterized as representing some sort of ‘heresy’.
Heresy, is commonly defined as ‘an opinion or doctrine at variance with the official or orthodox position’. So where does this idea come from, and why is it now ’emerging’?
[Read more…] about Consensus as the New Heresy
) () () This is just a pointer to a ‘Quick Study’ guide on The physics of climate modelling that appears in Physics Today this month, and to welcome anyone following through from that magazine. Feel free to post comments or questions about the article here and I’ll try and answer as many as I can.
Statements often appear in the media about suggesting that more extreme mid-latitude storms will result from global warming. For instance, western Norway was recently battered by an unusually strong storm which triggered many such speculations. But scientific papers on how global warming may affect the mid-latitude storms give a more mixed picture. In a recent paper by Bengtsson & Hodges (2006), simulations with the ECHAM5 Global Climate Model (GCM) were analysed, but they found no increase in the number of mid-latitude storms world-wide. Another study by Leckebusch et al. (2006) showed that the projection of storm characteristics was model-dependent. (Note that the dynamics of tropical and mid-latitude (often called ‘extra-tropical’) storms involve different processes, and tropical storms have been discussed in previous posts here on RC: here, here, here, and here).
The factors that control this are often confounding and so make this a tricky prediction. Simple arguments based on the expected ‘polar amplification‘ and the fact that the surface temperature gradient between the tropics and the poles will likely decrease would reduce the scope for ‘baroclinic instability’ (the main generator of mid-latitudes storms). However, there are also increases in the upper troposphere/lower stratospheric gradients (due to the stratosphere cooling and the troposphere warming) and that has been shown to lead to increases in wind speeds at the surface. And finally, although latent heat release (from condensing water vapour) is not a fundamental driver of mid-latitude storms, it does play a role and that is likely to increase the intensity of the storms since there is generally more water vapour available in warmer world. It should also be clear that for any one locality, a shift in the storm tracks (associated with phenomena like the NAO or the sea ice edge) will often be more of an issue than the overall change in storm statistics.
[Read more…] about On Mid-latitude Storms