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The tragedy of climate commons

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Translations: (Svenska)

Imagine a group of 100 fisherman faced with declining stocks and worried about the sustainability of their resource and their livelihoods. One of them works out that the total sustainable catch is about 20% of what everyone is catching now (with some uncertainty of course) but that if current trends of increasing catches (about 2% a year) continue the resource would be depleted in short order. Faced with that prospect, the fishermen gather to decide what to do. The problem is made more complicated because some groups of fishermen are much more efficient than the others. The top 5 catchers, catch 20% of the fish, and the top 20 catch almost 75% of the fish. Meanwhile the least efficient 50 catch only 10% of the fish and barely subsist. Clearly, fairness demands that the top catchers lead the way in moving towards a more sustainable future.

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ACRIM vs PMOD

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Translations: (Italian)

Two recent papers (Lockwood & Fröhlich, 2008 – ‘LF08’; Scafetta & Willson, 2009 – ‘SW09’) compare the analysis of total solar irradiance (TSI) and the way the TSI measurements are combined to form a long series consisting of data from several satellite missions. The two papers come to completely opposite conclusions regarding the long term trend. So which one (if either) is right, then? And does it really matter?

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Monckton’s deliberate manipulation

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Our favorite contrarian, the potty peer Christopher Monckton has been indulging in a little aristocratic artifice again. Not one to be constrained by mere facts or observable reality, he has launched a sally against Andy Revkin for reporting the shocking news that past industry disinformation campaigns were not sincere explorations of the true uncertainties in climate science.
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Welcome to the fray

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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

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Translations: (Español)

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.

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Friday round-up

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Translations: (Español)

They knew all along?
A recent story in NYT: ‘Industry Ignored Its Scientists on Climate‘ has caught our attention.

Update: Marc Roberts’ take:

Latest skeptical song from Singer

This week, the annual European Geophysical Union (EGU)’s general assembly was held in Vienna. Friday afternoon, I went to one of the conference’s last talks to learn about the latest news from the climate skeptics (have to keep an open mind…). It was probably the talk with the smallest audience in the whole conference (see the photo, but note there were a couple of individuals who were not captured by camera), despite an unusually long slot (30 min) allocation.

singer.jpg And not much news, I’m afraid, apart from that SEPP plans to release it’s NIPCC’09 in May. I understand it will be a thick report (800 pages?). The main messages were (a) that GHGs were unimportant – allegedlly supported by Douglass et al. (2007), and (b) solar activity was the main reason for the recent global warming and the mechanism involved galactic cosmic rays (GCR).

I asked Singer how he could explain the most recent warming when there is no trend in the GCR-flux or other indices of solar activity since 1952. He countered by saying he was glad I asked him this question, and announced that he had done his thesis exactly on the topic solar wind and GCRs.

So I had to answer that I had written a book about solar activity and climate, and I repeated my question. He could not answer in the end – other than saying that we have to look at the data. I told him that we already have looked at the data (e.g. Richardsson et al 2002; Benestad, 2005; Lockwood & Frohlich, 2007), so I recommended him to read up on RC.

Yet more aerosols: Comment on Shindell and Faluvegi

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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

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Translations: (Italian)

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

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Translations: (Italian)

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.

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Breaking the silence about Spring

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Did you know that in 1965 the U.S. Department of Agriculture planted a particular variety of lilac in more than seventy locations around the U.S. Northeast, to detect the onset of spring — in turn to be used to determine the appropriate timing of corn planting and the like? The records the USDA have kept show that those same lilacs are blooming as much as two weeks earlier than they did in 1965. April has, in a very real sense, become May. This is one of the interesting facts that you’ll read about in Amy Seidl’s book, Early Spring, a hot-off-the-press essay about the impacts of climate change on the world immediately around us – the forest, the birds, the butterflies in our backyards.
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