As imitation is the sincerest form of flattery, we’ve naturally been delighted that a number of sites have sprung up over the past few years with missions complementary to our own focussing on the science of climate change. Last year, we were introduced to “climate ethics”, whose mission it is to focus on the ethical dimensions of climate change. Now there is “RealClimateEconomics”, whose aim it is to focus on the economic considerations surrounding climate change. Neither this site nor climateethics.org has any formal relationship with RealClimate, despite the similarity in name. We do nonetheless welcome them to the fray. We are pleased to add them to our blogroll, which we hope has become a useful resource for those wishing to explore the broader discourse on climate change that lies beyond the science.
Hit the brakes hard
) There is a climate splash in Nature this week, including a cover showing a tera-tonne weight, presumably meant to be made of carbon (could it be graphite?), dangling by a thread over the planet, and containing two new articles (Allen et al and Meinshausen et al), a “News & Views” piece written by two of us, and a couple commentaries urging us to “prepare to adapt to at least 4° C” and to think about what the worst case scenario (at 1000 ppm CO2) might look like.
At the heart of it are the two papers which calculate the odds of exceeding a predefined threshold of 2°C as a function of CO2 emissions. Both find that the most directly relevant quantity is the total amount of CO2 ultimately released, rather than a target atmospheric CO2 concentration or emission rate. This is an extremely useful result, giving us a clear statement of how our policy goals should be framed. We have a total emission quota; if we keep going now, we will have to cut back more quickly later.
Yet more aerosols: Comment on Shindell and Faluvegi
Guest post from Drew Shindell, NASA GISS
Our recent paper “Climate response to regional radiative forcing during the twentieth century”, has generated some interesting discussion (some of it very ‘interesting’ indeed). So this post is an attempt to give a better context to the methods and implications of the study.
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Aerosol effects and climate, Part II: the role of nucleation and cosmic rays
) Guest post by Bart Verheggen, Department of Air Quality and Climate Change , Energy research Institute of the Netherlands (ECN)
In Part I, I discussed how aerosols nucleate and grow. In this post I’ll discuss how changes in nucleation and ionization might impact the net effects.
Cosmic rays
Galactic cosmic rays (GCR) are energetic particles originating from space entering Earth’s atmosphere. They are an important source of ionization in the atmosphere, besides terrestrial radioactivity from e.g. radon (naturally emitted by the Earth’s surface). Over the oceans and above 5 km altitude, GCR are the dominant source. Their intensity varies over the 11 year solar cycle, with a maximum near solar minimum. Carslaw et al. give a nice overview of potential relations between cosmic rays, clouds and climate. Over the first half of the 20th century solar irradiance has slightly increased, and cosmic rays have subsequently decreased. RC has had many previous posts on the purported links between GCR and climate, e.g. here, here and here.
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Aerosol formation and climate, Part I
) Guest post by Bart Verheggen, Department of Air Quality and Climate Change , Energy research Institute of the Netherlands (ECN)
The impacts of aerosols on climate are significant, but also very uncertain. There are several reasons for this, one of which is the uncertainty in how and how fast they are formed in the atmosphere by nucleation. Here, in part I, I’ll review some of the basic processes that are important in determining the climate effects of aerosols, focusing in particular on their formation. This is also relevant in order to better understand –and hopefully quantify- the hypothetical climate effects of galactic cosmic rays which I’ll discuss in a follow-up post.
Farewell to our Readers
We would like to apologize to our loyal readers who have provided us so much support since we first went online in December 2004. However, after listening to the compelling arguments of the distinguished speakers who participated in the Heartland Institute’s recent global warming contrarian conference, we have decided that the science is settled — in favor of the contrarians. Indeed, even IPCC chair Rajendra Pachauri has now admitted that anthropogenic climate change was a massive hoax after all. Accordingly, RealClimate no longer has a reason for existence. The contrarians have made a convincing case that (a) global warming isn’t happening, (b) even if it is, its entirely natural and within the bounds of natural variability, (c) well, even if its not natural, it is modest in nature and not a threat, (d) even if anthropogenic warming should turn out to be pronounced as projected, it will sure be good for us, leading to abundant crops and a healthy environment, and (e) well, it might actually be really bad, but hey, its unstoppable anyway. (Can we get our check now?)
With all due respect…
) There was a great comedy piece a few years back (whose origin escapes us) that gave examples of how the English would use their language when speaking to a non-native speaker to imply the precise opposite of what was actually being understood. This allowed the English to feel superior without actually damaging international relations. One example was the phrase “with all due respect” which is generally understood to imply that the speaker has a great deal of respect for their counterpart, while the speaker is actually implying that they have no respect in the slightest for their interlocutor. The respect due being precisely zero.
This thought occurred to us when a few of us opened our email this week to see a draft ad being sent around by the Cato Institute (i.e. Pat Michaels) looking for signatories prior to being published in “major US newspapers” sometime soon:
Advice for a young climate blogger
) () Congratulations! You have taken the first step towards attempting to communicate your expertise and thoughts to the wider world, which remains poorly served by its traditional sources of information when it comes to complex societally relevant issues like climate change. Your aim to clarify the science (or policy options or ethical considerations or simply to explain your views) is a noble endeavor and we wish you luck and wide readership. But do be aware that you are dipping your blog into sometimes treacherous waters. Bad things can happen to good bloggers. So in a spirit of blog-camaraderie, and in light of our own experiences and observations, we offer some advice that may be of some help in navigating the political climate relatively unscathed.
Bushfires and extreme heat in south-east Australia
) () () Guest commentary by David Karoly, Professor of Meteorology at the University of Melbourne in Australia
On Saturday 7 February 2009, Australia experienced its worst natural disaster in more than 100 years, when catastrophic bushfires killed more than 200 people and destroyed more than 1800 homes in Victoria, Australia. These fires occurred on a day of unprecedented high temperatures in south-east Australia, part of a heat wave that started 10 days earlier, and a record dry spell.
This has been written from Melbourne, Australia, exactly one week after the fires, just enough time to pause and reflect on this tragedy and the extraordinary weather that led to it. First, I want to express my sincere sympathy to all who have lost family members or friends and all who have suffered through this disaster.
There has been very high global media coverage of this natural disaster and, of course, speculation on the possible role of climate change in these fires. So, did climate change cause these fires? The simple answer is “No!” Climate change did not start the fires. Unfortunately, it appears that one or more of the fires may have been lit by arsonists, others may have started by accident and some may have been started by fallen power lines, lightning or other natural causes.
Maybe there is a different way to phrase that question: In what way, if any, is climate change likely to have affected these bush fires?
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A global glacier index update
) () Guest commentary by Mauri Pelto
For global temperature time series we have GISTEMP, NCDC and HadCRUT. Each has worked hard to assimilate global temperature data into reliable and accurate indices of global temperature. The equivalent for alpine glaciers is the World Glacier Monitoring Service’s (WGMS) record of mass balance and terminus behavior. Beginning in 1986, WGMS began to maintain and publish the collection of information on ongoing glacier changes that had begun in 1960 with the Permanent Service on Fluctuations of glaciers. This program in the last 10 years has striven to acquire, publish and verify glacier terminus and mass balance measurement data from alpine glaciers the world over on a timely basis. Spearheaded by Wlfried Haeberli with assistance from Isabelle Roer, Michael Zemp, Martin Hoelzle, at the University of Zurich, their efforts have resulted in the recent publication, “Global Glacier Changes: facts and figures” published jointly with UNEP. This publication summarizes the information collected and submitted by the national correspondents of WGMS portraying the global response of glaciers to climate change, as well as the regional response.