Friday, April 08, 2011

Climate Crunch

Deconstructing Conclusions
During the winter of 2009-2010 I began investigating climate science, and since then have been reading in the field on-and-off. Again this last winter I have been reading way too much, trying to get to the bottom of various intricacies of the coupled earth-human system. Suffice to say, the Earth's climate is extremely complex, and every scientific sub-discipline has made its own peace with the devil in the details. Getting to the bottom of what scientists believe, and why, is no easy task, and after more than a year of research I have learned a huge amount about the Earth, but still am not definitively convinced about every aspect of climate change science.

This is as it should be. Science is complex and ever-evolving, and the Earth is a very, very complicated place. But provisional results and untested assumptions, although ever-present, make soft bedrock for climate policy. The truth is that we simply do not understand many of the key issues, such as feedbacks, in the climate system.

Many issues, such as divergence in tree-ring proxy records, don't by themselves discredit the theory of anthropogenic global warming, even if scientists can't explain everything. But they do begin to cast doubts. The issue of "hide the decline" probably falls into this category, because although some scientists chose to substitute instrument data for the misbehaving paleo data, the divergance can be explained. But is this explanation just hand-waving? How do we really know what happened hundreds or thousands of years ago? Obviously climate proxies may be complicated, idiosyncratic, and only reliable under certain conditions. It has been said that "trees are not thermometers," but this admission, even if carefully defined, can lead to increasing skepticism.

Unresolved Issues
Skeptic Science (SkS) has a great index of skeptic arguments, many of which continue to be problematic. They attempt to "refute" each argument, and they are the best source for good answers to most of these issues. But not every question can be answered definitively. Sometimes one question simply leads to three or four more. For example, they point out that warming is not due to the sun....but it is very, very, complicated. SkS explains why CO2 lags temperature in paleoclimate....but their response is not good system thinking, doesn't address the skeptic arguments about what the Vostok ice core means, and isn't especially convincing.

I've been researching climate change for over a year, and still am not close to understanding many of the major issues. What's worse, I can't find good evidence that the climate scientists understand all of the issues either! Much of science is dependent on good faith and trust, but at some point an explanation has to be convincing. Some theories (and I would put String Theory and Global Warming into this category) are too gnarly to be comprehended by mere mortals. They may be true, but I can't believe in what I don't understand.

The bottom line is that, if you really want to know,... its complicated. I'm officially revoking my previous conclusion, pending better explanations of the science. Maybe I'll have to wait to believe the models until they're proved true: until then I'll continue to entertain belief in multiple possibilities about this weird, beautiful world we live on.

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