Una traducción está disponible aquí.
A biased economic analysis of geoengineering
) Greenhouse gases
) PETM Weirdness
The Paleocene-Eocene Thermal Maximum (PETM) was a very weird period around 55 million years ago. However, the press coverage and discussion of a recent paper on the subject was weirder still.
Bubkes
) () Some parts of the blogosphere, headed up by CEI (“CO2: They call it pollution, we call it life!“), are all a-twitter over an apparently “suppressed” document that supposedly undermines the EPA Endangerment finding about human emissions of carbon dioxide and a basket of other greenhouse gases. Well a draft of this “suppressed” document has been released and we can now all read this allegedly devastating critique of the EPA science. Let’s take a look…
Hit the brakes hard
) Una traducción está disponible aquí.
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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It’s wrong to wish on space hardware
A number of satellite related issues have come up this weekend: The NSIDC reminded us that satellite sensors are (like all kinds of data) not perfectly reliable and do not last forever. Two satellites collided by accident last week, littering the orbit with dangerous amounts of debris. In San Diego this weekend, I was fortunate enough to attend a meeting with some of the Apollo astronauts and some of the scientists involved in Cassini and the Mars Phoenix missions. And yesterday morning we heard that the Orbiting Carbon Observatory mission launch failed to insert the satellite into orbit, and it is presumably measuring carbon dioxide somewhere at the bottom of the Southern Ocean. Coincidentally, when it came up on the news, I was in a meeting with one of the scientists who had been working on setting up a climate model to assimilate the OCO data in order to pin down the carbon sinks.
All of these events have served to remind me at least, that although the space age is 50 years old, we are a long way from the point where we can take our ability to launch and control off-planet machines for granted. Getting into space was, and remains, a tremendous challenge. This makes the successes we’ve had all the more incredible, and a testament to the hard work the engineers and scientists do over many years before a launch to give the missions the best chance of success.
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Simple Question, Simple Answer… Not
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) () Guest commentary by Spencer R. Weart, American Institute of Physics
I often get emails from scientifically trained people who are looking for a straightforward calculation of the global warming that greenhouse gas emissions will bring. What are the physics equations and data on gases that predict just how far the temperature will rise? A natural question, when public expositions of the greenhouse effect usually present it as a matter of elementary physics. These people, typically senior engineers, get suspicious when experts seem to evade their question. Some try to work out the answer themselves (Lord Monckton for example) and complain that the experts dismiss their beautiful logic.
The engineers’ demand that the case for dangerous global warming be proved with a page or so of equations does sound reasonable, and it has a long history. The history reveals how the nature of the climate system inevitably betrays a lover of simple answers.
Friday round-up
Blogging has been a little light recently (apologies!), but here are a few pieces that have caught our eye this week.
First up, the Columbia Journalism Review has a two–parter on journalistic coverage of climate change inspired by comments from Jeff Huggins on the Andy Revkin’s Dot Earth blog. The key issues CJR addresses are familiar ones to readers here: how to communicate mainstream science in a way that doesn’t distort the reality of the consensus on many issues in favour of controversy on more cutting-edge topics. Definitely worth a read, and proof (if such were needed) that commenting on blogs can make a difference to coverage.
Next, the role of CO2 as a long-term climate forcing. The old CO2 lead/lag issue keeps making the rounds as a contrarian talking point (and made a brief resurgence here in comments this week) despite the fact that the existence of impact of climate on the carbon cycle in no way invalidates the impact of CO2 (as a greenhouse gas) on climate. However, there is a nice paper in Nature this week (Lunt et al, 2008) which looks at the various proposed triggers for the onset of the quaternary glaciations at the end of the Pliocene (~3 million years ago). These triggers involve, permanent El Nino events, the closing of the Isthmus of Panama, changes in orbital forcing, tectonic uplift of the Rocky mountains – and long-term decreases in CO2 as a function of very slow variations in sea floor spreading and chemical weathering. Lunt et al find that only the change in CO2 (400 ppm to 280 ppm) can explain the changes in the ice sheet. None of the other ideas come even close.
Thus, it looks very much like the climate changed radically due to this externally forced drift in CO2 (and tectonic is external for climate purposes on this timescale). As a corollary, this is an expansion of the idea we discussed a few months back, that the long term changes in the Earth system due to external forcings might be well be larger than the classical (Charney) sensitivity we often talk about.
Third. There has been a lot of discussion on energy futures in the comments – Nature had a good rundown of the scientific constraints on the different prospects. But this video is a quite entertaining discussion of why we just can’t get our heads around the issue from Dan Gilbert (h/t GH).
Finally, a commentary on the prospects for continued employment as an Arctic ice expert (h/t Climate Feedback).
Once more unto the bray
We are a little late to the party, but it is worth adding a few words now that our favourite amateur contrarian is at it again. As many already know, the Forum on Physics and Society (an un-peer-reviewed newsletter published by the otherwise quite sensible American Physical Society), rather surprisingly published a new paper by Monckton that tries again to show using rigorous arithmetic that IPCC is all wrong and that climate sensitivity is negligible. His latest sally, like his previous attempt, is full of the usual obfuscating sleight of hand, but to save people the time in working it out themselves, here are a few highlights.
Aerosols, Chemistry and Climate
Everyone can probably agree that the climate system is complex. Not only do the vagaries of weather patterns and ocean currents make it hard to see climate changes, but the variability in what are often termed the Earth System components complicates the picture enormously. These components – specifically aerosols (particulates in the air – dust, soot, sulphates, nitrates, pollen etc.) and atmospheric chemistry (ozone, methane) – are both affected by climate and affect climate, since aerosols and ozone can interact, absorb, reflect or scatter solar and thermal radiation. This makes for a rich research environment, but can befuddle the unwary.
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