Monday, December 5, 2011

Climate Change Skepticism

Some climate change skeptics who are very dear to me keep expressing puzzlement over why I'm not outraged by the series of leaked emails that constitute "Climategate". Specifically why do I not conclude from them that the best information that we have at present should not make us confident that anthropogenic climate change is real.

I thought I'd explain and give climate change skeptics something easy to attack. A positive argument.

  1. A conspiracy is only damaging if it is effective. A bunch of ineffectual twits sitting around a table plotting is of no danger to anyone. Leaked emails tell us where to look for evidence of damage
    but are not, by themselves, evidence of damage.
  2. If there were an effective conspiracy to doctor data to create a false consensus then it could only have been successful in creating a false consensus if there are papers that depend on doctored data.
    1. If so, it should be easy to find examples, via the paper citation graph, and present them.
    2. According to the skeptics, 1000's of scientists are outraged (outraged I tell you) that "the whole thing is a fraud" which permeates the IPCC and the climatological profession. Being scientists, they should be able to follow citations to find those papers. That they haven't over a year after the first "climategate" is reason enough to conclude tentatively that
      they can't.
  3. If there were an effective conspiracy to claim a consensus where none exists, then there should be plenty of paleo-climatologists who assume the contrary position in the peer-reviewed literature. Oreskes et al. is a positive example of a survey that argues they assume climate change is real.
    1. If there were an effective conspiracy to suppress the vast majority of research papers then there would be a large number of quality research papers that have been rejected and a large number of disaffected climatologists who would be clamoring to create their own journals, conferences, and review boards. This has not happened in the decades during which climate change has been discussed. Why not?
    2. The unsanitized rejected papers would have data that is substantially different from the sanitized mainstream literature or draw starkly different conclusions from the same data. The BEST study from Berkeley is positive evidence against the first. The second requires a large effective conspiracy as in (4).
  4. If there is a large, effective conspiracy that includes the majority of climatologists, then again, their data would have to be faked or their conclusions would not follow from this data.
    1. If their data is cooked, it would show. Again, the BEST study from Berkeley is positive evidence against this claim.
    2. If they make up false conclusions, then the evidence is in the literature, and there would have to be some mechanism by which large numbers of scientists coordinate to avoid contradictions that are obvious to lay-people. What is this mechanism?
  5. Conclusion: If the data is not cooked (not 2), paleo-climatologists genuinely try to draw reliable conclusions from their data (not 4), and paleo-climatologists genuinely agree that anthropogenic climate-change is real (not 3) after decades of research, then the best available information says that anthropogenic climate change is real.

If you are a climate change skeptic who wants to convince me of your position, argue against these propositions or present positive evidence. I would love to see any of the following:

  1. Papers that have been infected with cooked data, ideally including a proportion of the citation graph that depends on these papers.
  2. A survey of the recent existing literature that shows that many paleo-climatologists make assumptions inconsistent with anthropogenic climate change. Ideally, this study would compare the proportion of historians of 20th century Europe who believe the holocaust did not happen with the proportion of paleo-climatologists who believe anthropogenic climate change did not happen.
  3. A comparison of the data in papers that were rejected due to the conspiracy and those that were rejected because they were genuinely crap.
  4. A coordinating organization that helps large numbers of conspiratorial scientists to come up with non-obviously-contradictory non-sequiturs based on real data.

I am not going to waste my time looking at:

  1. Damning emails. These are at best pointers where to look for evidence of damage caused by a conspiracy. I've worked too long with databases to be impressed by hysterical emails claiming "the data is all corrupt". When you dig into the problem, usually there isn't one, and most of the rest of the time some forensic work with logs and backups will let me recover the ground truth. Emails are the least reliable signal. Demonstrated damage in dependent applications is the best, and logs that allow forensic analysis are a distant second.
  2. Lists of dissenters. I've looked at a few of these lists and the ones I've checked are full of non-climatologists, economists, and weather forecasters. I'm sure they're lovely people and most of them are probably competent in their own domains, but they are not competent on the question of "is anthropogenic climate change real?" "A Scientific Dissent from Darwinism is another scientist list in a different domain that I find equally unconvincing. If you understand why I find Project Steve so funny, you'll understand why I find your lists unimpressive.