Andrew Dessler’s Posts

• Why you should believe the IPCC, part 134,992,653

  The ideological tensions inside the IPCC gives its reports alarming credibility 2

  Posted 8 months, 1 week ago

  Over on DotEarth, Andy Revkin has an interesting post about the "burning embers" diagram from the latest IPCC. The upshot of the story is that several countries well-known for their desire to do nothing about climate change were able to remove an alarming figure from the 2007 report:

  The diagram, known as "burning embers," is an updated version of one that was a central feature of the panel's preceding climate report in 2001. The main opposition to including the diagram in 2007, they say, came from officials representing the United States, China, Russia and Saudi Arabia.

  People who argue… Read More

• Looking for validation

  The problem with climate-model criticism 4

  Posted 8 months, 2 weeks ago

  I have a paper [PDF] in this week's Science discussing the water vapor feedback. It is a Perspective, meaning that it is a summary of the existing literature rather than new scientific results. In it, my co-author Steve Sherwood and I discuss the mountain of evidence in support of a strong and positive water vapor feedback.

  Interestingly, it seems that just about everybody now agrees water vapor provides a robustly strong and positive feedback. Roy Spencer even sent me email saying that he agrees.

  What I want to focus on here is model verification. If you read the blogs,… Read More

• Attack of the zombies: global cooling! 0

  Posted 8 months, 3 weeks ago

  John Fleck comments on George Will's latest zombie attack: in the 1970s, scientists said the Earth was cooling!

  What's amazing is not that George Will is selectively quoting to mislead the reader, but that he continues to do so after John sent him a copy of the article in question:

  When George Will last wrote about this subject, last May, I sent him a copy of the Science News article he misleadingly quoted in the example I used above. I got a nice note back from him thanking me for sharing it.

  I'll leave it to the reader to… Read More

• Me, on the interwebs

  Online climate chat: Tuesday, Feb. 10, at 12:45 pm CST 2

  Posted 9 months ago

  This Tuesday (Feb. 10, 2009) I'll be doing an online chat over on Eric Berger's SciGuy website. We'll be talking about climate, climate change, and everything else climate related. It will be at 12:45 pm CST. If you can't make it, the transcript will be posted (I'll put a link to it in the comments).

• Negative climate feedback is as real as the Easter Bunny

  There is no negative feedback in the climate system 51

  Posted 9 months, 2 weeks ago

  The small number of credible skeptics out there (e.g., Spencer, Lindzen) have spent much of the last decade searching for a negative feedback in our climate system. If a sufficiently big one is found, then it would suggest that warming over the next century may well be small.

  Most climate scientists, however, are reasonably certain that a negative feedback big enough to overwhelm the well-known positive feedbacks in the climate system, such as the water vapor feedback [PDF], does not exist. Why?

  Negative feedbacks tend to dampen out climate change. If you add greenhouse gases to the atmosphere or… Read More

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Andrew Dessler’s Recent Comments

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  Uncertainty agenda

  Christophersj-

  You are correct.  Uncertainty is one of the key arguments made by skeptics, but it's really quite bogus.  I've blogged about this here (also see links therein).

  Thanks!
  On There is no negative feedback in the climate system posted 8 months, 3 weeks ago 51 Responses

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  Archive of chat

  can be obtained here.On Online climate chat: Tuesday, Feb. 10, at 12:45 pm CST posted 8 months, 4 weeks ago 2 Responses

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  typo in title

  Sam-

  In the original version of the post, I had the word "forcing" in the title, but have changed it to "feedback."  

  Now, on to your question.  Aerosols are a forcing of the climate, because they directly change the radiative balance of the planet.  A feedback is a process that responds to an initial warming, and either reinforces (positive) or ameliorates (negative) the initial warming.  Sorry for the confusion.On There is no negative feedback in the climate system posted 9 months, 2 weeks ago 51 Responses

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  A few thoughts ...

  Colin Wright-

  My interpretation of the IPCC results is that there is about a 50% chance that warming will be greater than 3°C if we do nothing to rein in greenhouse gas emissions.  It is very difficult to establish a probability for unlikely but high consequence events, such as release of methane from clathrates or tundra --- so the answer is I don't really have a good probability estimate.

  The article about spraying water into the atmosphere is interesting.  I am quite uncertain as to whether it would actually work, and I am extremely doubtful that it would be practical.  In general, geoengineering solutions are really a last resort, if every other approach has failed and you're heading for the abyss.  

  For this kind of application, the best place to inject water (and minimize the greenhouse effect of the gas) would be in places where the atmosphere is basically isothermal, which is likely high latitudes.

  JMG-

  The poll is just for fun.  As you correctly surmise, it is not a confident measure of anything.
  On Why large future warming is very likely posted 10 months ago 5 Responses

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  wow

  Those articles are terribly misleading, by any standard.  I hope the author is good at saying, "do you want fries with that?"  In her next career, which I predict will be starting soon, she'll need that skill.On Beltway paper runs two of the dumbest stories of the decade on climate science posted 11 months, 2 weeks ago 18 Responses