In 2004 Stephen Pacala and Robert Socolow published a paper in Science in which they argued that a pragmatic, but still difficult, way of stabilizing atmospheric CO2 levels over the long term was via the implementation of seven “stabilization wedges” over the next 50 years. The idea was very simple: each wedge represented one in-hand technology or societal practice that could be implemented, relatively slowly at first and increasing linearly with time, to make a small but growing dent in the rise in CO2 emissions, stabilizing them at 2004 levels (about 7 Gigatons C/Year) over the next 50 years (see figure below).
[Read more…] about The high cost of inaction
Greenhouse gases
Volcanic vs. Anthropogenic CO2
Guest Commentary by Terry Gerlach*
TV screen images of erupting and exploding volcanoes spewing forth emissions are typically spectacular, awesome, and vividly suggestive of huge additions of gas to the atmosphere. By comparison, the smokestack and exhaust pipe venting of anthropogenic emissions is comparatively unexciting, unimpressive, and commonplace. Consequently, it easy to get traction with the general public for claims that volcanic CO2 emissions are far greater than those of human activities, or that the CO2 released in some recent or ongoing eruption exceeds anthropogenic releases in all of human history, or that the threat of a future super-eruption makes concerns about our carbon footprint laughable. The evidence from volcanology, however, does not support these claims.
[Read more…] about Volcanic vs. Anthropogenic CO2
Lu: from ‘interesting but incorrect’ to just wrong
Some readers might recall a story from a couple of years of ago relating polar ozone depletion to cosmic rays and the subsequent failure of predictions made using that theory. The idea came from from a Qian-B. Lu (U. Waterloo), and initially seemed interesting (at least to those of us who were not specialists). Perhaps cosmic ray induced chemistry was playing some part in releasing chlorine from CFCs as well as the more accepted idea of heterogeneous chemistry on polar stratospheric particles? Lu’s predictions for increased polar ozone loss in 2008/2009 as a function of the low solar activity (and therefore higher CR flux) did not come to pass. Worse (for this idea), new analyses demonstrated that the hypothesized CR-induced CFC loss wasn’t detectable at all.
[Read more…] about Lu: from ‘interesting but incorrect’ to just wrong
Fracking methane
The Howarth et al paper estimating the climatic impact of shale gas extraction by hydraulic fracturing (fracking) has provoked a number of responses across the media. Since the issue of natural gas vs. coal or oil, and the specifics of fracking itself are established and growing public issues, most commentary has served to bolster any particular commenter’s prior position on some aspect of this. So far, so unsurprising. However, one aspect of the Howarth study uses work that I’ve been involved in to better estimate the indirect effects of short-lived emissions (including methane, the dominant component of shale gas). Seeing how this specific piece of science is being brought into a policy debate is rather interesting.
[Read more…] about Fracking methane
From blog to Science
There is a lot of talk around about why science isn’t being done on blogs. It can happen though, and sometimes blog posts can even end up as (part of) a real Science paper. However, the process is non-trivial and the relatively small number of examples of such a transition demonstrate clearly why blog science is not going to replace the peer-reviewed literature any time soon.
Getting things right
Last Monday, I was asked by a journalist whether a claim in a new report from a small NGO made any sense. The report was mostly focused on the impacts of climate change on food production – clearly an important topic, and one where public awareness of the scale of the risk is low. However, the study was based on a mistaken estimate of how large global warming would be in 2020. I replied to the journalist (and indirectly to the NGO itself, as did other scientists) that no, this did not make any sense, and that they should fix the errors before the report went public on Thursday. For various reasons, the NGO made no changes to their report. The press response to their study has therefore been almost totally dominated by the error at the beginning of the report, rather than the substance of their work on the impacts. This public relations debacle has lessons for NGOs, the press, and the public.
[Read more…] about Getting things right
The A-train
A little behind schedule, I finally found time to read the article in the July 2010 edition of Physics Today “Touring the atmosphere aboard the A-Train” by Tristan S. L’Ecuyer and Jonathan H. Jiang. I think this article is a worth-while read, telling a fascinating story about how new satellite missions lead to greater understanding of our climate system.
Happy 35th birthday, global warming!
) (
) (
) Global warming is turning 35! Not only has the current spate of global warming been going on for about 35 years now, but also the term “global warming” will have its 35th anniversary next week. On 8 August 1975, Wally Broecker published his paper “Are we on the brink of a pronounced global warming?” in the journal Science. That appears to be the first use of the term “global warming” in the scientific literature (at least it’s the first of over 10,000 papers for this search term according to the ISI database of journal articles).
In this paper, Broecker correctly predicted “that the present cooling trend will, within a decade or so, give way to a pronounced warming induced by carbon dioxide”, and that “by early in the next century [carbon dioxide] will have driven the mean planetary temperature beyond the limits experienced during the last 1000 years”. He predicted an overall 20th Century global warming of 0.8ºC due to CO2 and worried about the consequences for agriculture and sea level.
Recent trends in CO2 emissions
Guest commentary by Corinne Le Quéré, Michael R. Raupach, and Joseph G. Canadell
There is a letter in Nature Geoscience this month by Manning et al (sub. reqd.) “Misrepresentation of the IPCC CO2 emission scenarios” discussing some recent statements about the growth rates of CO2 emissions compared to the IPCC scenarios that informed the climate modeling in the last IPCC report. In it they refer to results published by us and colleagues in a couple of recent papers (Raupach et al. 2007; Le Quéré et al. 2009), and to statements made by others on the basis of our results (Ganguly et al. 2009; Anderson et al. 2008; Reichstein 2010). Specifically, Manning et al object to the claim that “current CO2 emissions from fossil fuel burning were higher than the values used in climate projections by the IPCC”.
We agree with the Manning et al’s main point, and appreciate the chance to provide some clarification on the graph in question and subsequent use of our result. To be specific, recent emissions were not higher than each and every one of the climate projections by the IPCC, as has been claimed by some other studies citing our work, although they were near the top end of the range.
So what is the claim of ‘misrepresentation’ based on?
[Read more…] about Recent trends in CO2 emissions
Climate change commitments
) There is an interesting letter in Nature Geoscience this month on what climate changes we have actually already committed ourselves to. The letter, by Mathews and Weaver (sub. reqd.), makes the valid point that there are both climatic and societal inertias to consider.