Saturday, January 3, 2015

Evaluating Global Warming Science

Usually science deals with phenomena that doesn't matter except to the scientists studying it.  There aren't many people who care about gravity waves except physicists studying gravity waves in the infant universe.  When science proceeds in this fashion, it can go in fits and starts, only eventually converging on strong evidence that can be widely accepted.  For example, after great effort, BICEP and BICEP2 purport to find the evidence, but then objections emerge and physicists looked further.

 But sometimes the topic matters, a lot, to everyone, like global warming.  How do we proceed?  For gravity waves we can withhold our judgement waiting for the physicists to reach consensus.  But we do not have that luxury when it comes to global warming.  The scientific evidence is presented and debated by the scientists taking a winding path as science usually does, but what do we do when the outcome is so important?

I have some expertise in data analysis, so I am able to make judgements about the evidence the scientists present.  But I'm not a climate scientist, so I need another approach to the evaluation of the science.  Let me give an example.  Evolution is another hot topic with people taking sides.  The evidence for evolution is overwhelming, more than we have for gravity.  Still there are people who want, for religious reasons, to deny or at least modify it to allow for intervention of a deity.  Michael Behe is just such a person.  He has tried again and again, but the beatback is stunning.  It's like watching a Rafael Nadal taking an unranked player to school.  That is what I see in the back and forth between the climate scientists and the deniers.  Over and over again the deniers are taken to school.

But where this becomes important is when the evidence is not there.  Who are we going to back to elucidate that evidence, the team that has been winning or the ones that haven't.  An "analysis" has been circulating among the deniers that asserts that global temperatures are declining.  The analysis however is a classic example of "lying with statistics".  The Cato Institute, which I've posted about previously, presented an article making the essentially the same claim, the global temperatures have declined in the last 18 years.  They since realized that the article was a mistake and they got someone else to redo the analysis(pdf) and found a small increase in global temperatures, not a decline. 

Ok, a small increase in global temperature, what are we to make of that?  Cato Institute wants us to make very little of it.  But what team should put our confidence in?  I put mine in the climate scientists, and it has been rewarded.  We find out that global atmospheric temperatures have slowed down, but instead have been absorbed by the oceans.  In fact global warming hasn't slowed down at all, but has been distributed differently.  And is that better or worse for us?