Climate change redux

It’s that time of year again.  As much of the country swelters, in what seems to be an annual event, conversation turns again to the topic of global climate change.  Is the heat a sign of global warming?  What about this past winter?   Were the huge snowfalls blanketing the east coast another sign that something is awry with our climate, or did the wintry weather help bring the whole global warming debate into question?

Where one stands on global climate change depends largely on where one sits politically.  About 86% of Democrats believe that global climate change is occurring, and, depending on how the question is phrased, roughly half of Republicans.  A much smaller percentage of Republicans, however, believe the climate is being affected by human activity.

I’ll never forget when, during my first year as a professor, my department received an e-mail from a local lawyer asking that we provide feedback to him about a letter he’d written asserting that global climate change had no basis in fact (he was, however, very concerned about the potential shift in the earth’s polarity).  I guess it hadn’t dawned on this particular lawyer that there were more proper authorities to consult on the issue of global warming than a department of historians and political scientists.  For him, the science didn’t matter.

Still, I have always wished I’d written back to the man. I’m not totally, after all, totally unqualified to comment on the matter (although admittedly not as qualified as a certain distant relative of mine).  As someone who is almost finished a book manuscript about research and scientific methodology, I have a pretty good feel for how the science works, even if I may not be aware of the specific statistical models and (often too closely guarded) datasets used in particular climatological studies.

First, the climate is almost certainly changing due to greenhouse gases, carbon dioxide foremost among them, being pumped into the environment.  Do I believe this because I’m a Democrat who “trusts elites” and because it’s a view that is diametrically opposed to the views of the dumbest member of the Senate?   Maybe that’s part of it, but the larger part is an understanding that the very basis of climatological inquiry involves the ability to statistically analyze the influence of greenhouse gases while controlling for other factors.

What other factors influence aggregate global temperatures?  Many.  El Ninos and Ninas, the North Atlantic Oscillation, increased solar activity, and numerous other factors influence global and regional climates and can even, for periods, subsume any consequences of man-made climate change. Often “climate skeptics” like to point to these other factors and have their “gotcha!” moment when they assert that it’s not greenhouse gases but “natural variation” that causes climate change.

Wow, if only scientists had only been as clever as these folk and thought of accounting for these other factors when calculating the net effect of carbon and other emissions.  But, of course, they have.

The best analogy for understanding how climatological studies work is to think about how epidemiologists came to the conclusion that cigarettes caused health problems.  Many things cause health problems, and the idea that something else could cause cigarette-related deaths was an idea repeatedly asserted by tobacco industry executives well into the nineties.  However, decades of studies that accounted for all these “other factors” repeatedly came to the same conclusion — all other things being equal, there was a clear trend between cigarette smoking and health problems.  As is the case with man-made climate change, the evidence collected through hundreds of study has continued to point in the same direction.

The evidence that has been collected about the effects of greenhouse gases on the climate up until this point, however, does only so much good in predicting the future effects of continued emissions.  One famous “skeptic” and author of some pretty cool novels, Michael Chrichton, justifiably criticized the faith some climatologists have put in simulation models of future climate change.  Since such models depend on difficult-to-know assumptions, future predictions of aggregate global temperature increases range from a modest degree or two, to a potentially catastrophic 10 degrees Fahrenheit or more.

The reason that it’s difficult to predict the future is due to the way that some of those “other factors” may mitigate or intensify global warming.  Increased cloud cover could help offset increased temperatures by reflecting light back into space.  On the other hand, the loss of snow and ice cover could have the opposite effect, as darker land and sea water absorbs increasing amounts of heat.  Even worse would be the release of large amounts of methane trapped in the world’s oceans. The biggest fear is a “runaway”-type affect as the effects of global warming creates a mutually reinforcing loop, with increased warming causing changes that warm the earth, which causes more changes, and so forth.

So what is to be done?  First, climate change “skeptics” need to ask themselves why they have such a hard time believing that greenhouse gases increase global temperatures.  It’s ironic that the same conspiratorial thinking about elites and clever-than-though attitude that lend themselves to a willingness to believe in strange things like a government coverup of 9-11 would also be associated with disbelief in a global phenomenon that might already have tragic consequences.

Second, we need to understand global climate change as a trend.  Blaming hot summers, cold winters, and particular hurricanes on greenhouse gases is silly.  Climate change trends take place over decades, not years, months, or seasons.  Just because some areas of the globe are cooling, doesn’t mean that aggregate temperatures aren’t rising.  At the same, data suggests that over time the trend tying emissions to temperature have become obvious, and the amount of carbon emissions will only increase in the coming years.

Finally, we need to deal honestly with the fact that some measures to reduce greenhouse emissions have real consequences.  Democrats often play their own denial game by playing up “green jobs” as a panacea for both economic growth and environmental preservation.  Agreements to restrict greenhouse gases at the national and international level increase energy prices and can lead to continued poverty for millions in underdeveloped countries.

A better mindset might be to think how a portion of the billions of dollars of economic growth that might be lost to draconian environmental regulation might instead be redirected toward the search for cleaner, more efficient technologies.  At the very least, a happy medium might be found between the need for economic and technological progress, and the recognition that global climate change will cause problems, potentially catastrophic problems, if we pretend the problem doesn’t exist.

The world is depending on the United States, the biggest greenhouse gas emitter by far, to get on board in the search for solutions.  For this to happen, those Americans who continue to deny that global climate change is a man-made phenomena need to get their heads out of the sand and stop thinking of science as an extension of politics.  Data doesn’t care what you want to believe.

Posted on July 22, 2011, in Uncategorized. Bookmark the permalink. 1 Comment.

  1. Nice writing, Doug.
    another more current measure of greenhouse emissions
    There’s a lot more to this question than carbon dioxide or halocarbons

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