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about Gavin Schmidt

Gavin Schmidt is a climate modeler, working for NASA and with Columbia University.

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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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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Wilkins ice shelf collapse

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Since people are wanting to talk about the latest events on the Antarctic Peninsula, this is a post for that discussion.

The imagery from ESA (animation here) tells the recent story quite clearly – the last sliver of ice between the main Wilkins ice shelf and Charcot Island is currently collapsing in a very interesting way (from a materials science point of view). For some of the history of the collapse, see our previous post. This is the tenth major ice shelf to collapse in recent times.

Maybe we can get some updates and discussion of potential implications from the people working on this in the comments….?

Advocacy vs. Science

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The advocate will pick up any piece of apparently useful data and without doing any analysis, decide that their pet theory perfectly explains any anomaly without consideration of any alternative explanations. Their conclusion is always that their original theory is correct.

The scientist will look at all possibilities and revise their thinking based on a thorough assessment of all issues – data quality, model quality and appropriateness of the the comparison. Their conclusion follows from the analysis whatever it points to.

Which one is which?

Michaels’ new graph

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Every so often people who are determined to prove a particular point will come up with a new way to demonstrate it. This new methodology can initially seem compelling, but if the conclusion is at odds with other more standard ways of looking at the same question, further investigation can often reveal some hidden dependencies or non-robustness. And so it is with the new graph being cited purporting to show that the models are an “abject” failure.

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Olympian efforts to control pollution

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There is a new paper in Science this week on changes to atmospheric visibility. In clear sky conditions (no clouds), this is related mainly to the amount of aerosols (particulate matter) in the air (but is slightly dependent on the amount of water vapour as well, which is corrected for in this study). The authors report that the clear-sky visibility has decreased almost everywhere (particularly in Asia) from 1973 to 2007, with the exception of Europe where visibility has increased (consistent with the ‘brightening trend’ reported recently). Trends in North American stations seem relatively flat.

There is another story that didn’t get as much press when it came out late last year but that is highly relevant to this issue – whether any of the efforts that the Chinese authorities to reduce air pollution ahead of the Olympics last year had any impact. To the extent that they did, they might point the way to reducing aerosols and other pollutants across Asia, but it might also reveal how hard it is to do so.
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What George Will should have written

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We’ve avoided piling on to the George Will kerfuffle, partly because this was not a new story for us (we’d commented on very similar distortions in previous columns in 2004 and 2007), but mostly because everyone else seems to be doing a great job in pointing out the problems in his recent columns.

We are actually quite gratified that a much wider group of people than normal have been involved in calling out this latest nonsense, taking the discussion well outside the sometimes-rarefied atmosphere of the scientific blogosphere (summary of links). Maybe RealClimate has succeeded in its original aim of increasing the wider awareness of the scientific context? However, like many, we are profoundly disappointed in the reaction of the Washington Post editors and George Will himself (though the ombudsman’s column today is a step in the right direction). It would have been pleasant to see an example of the conservative punditocracy actually learning something from the real world instead of resorting to ever-more unconvincing pseudo-legalistic justifications and attacks on the messenger to avoid taking their head out of the sand. Nonetheless, in a moment of naive optimism, we have allowed ourselves to indulge in a fantasy for how a more serious columnist might have dealt with the issue:
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It’s wrong to wish on space hardware

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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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On replication

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This week has been dominated by questions of replication and of what standards are required to serve the interests of transparency and/or science (not necessarily the same thing). Possibly a recent example of replication would be helpful in showing up some of the real (as opposed to manufactured) issues that arise. The paper I’ll discuss is one of mine, but in keeping with our usual stricture against too much pro-domo writing, I won’t discuss the substance of the paper (though of course readers are welcome to read it themselves). Instead, I’ll focus on the two separate replication efforts I undertook in order to do the analysis. The paper in question is Schmidt (2009, IJoC), and it revisits two papers published in recent years purporting to show that economic activity is contaminating the surface temperature records – specifically de Laat and Maurellis (2006) and McKitrick and Michaels (2007).

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Antarctic warming is robust

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The difference between a single calculation and a solid paper in the technical literature is vast. A good paper examines a question from multiple angles and find ways to assess the robustness of its conclusions to all sorts of possible sources of error — in input data, in assumptions, and even occasionally in programming. If a conclusion is robust over as much of this as can be tested (and the good peer reviewers generally insist that this be shown), then the paper is likely to last the test of time. Although science proceeds by making use of the work that others have done before, it is not based on the assumption that everything that went before is correct. It is precisely because that there is always the possibility of errors that so much is based on ‘balance of evidence’ arguments’ that are mutually reinforcing.
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