Climate science isn’t necessarily ‘settled’
BY JOHN R. CHRISTY
March 20, 2014
Why do we argue about climate change?
The reason there is so much contention regarding “global warming” is relatively simple to understand: In climate change science we basically cannot prove anything about how the climate will change as a result of adding extra greenhouse gases to the atmosphere.
So we are left to argue about unprovable claims.
We can measure and prove that greenhouse gases are increasing. And, in the laboratory, we can measure and prove that adding greenhouse gases to a jar of air will lead to further warming.
But when it comes to how the actual climate system might respond to extra greenhouse gases, we’re out of luck in terms of “proof” because the climate’s complexities are innumerable and poorly understood.
Climate science is a murky science. When dealing with temperature variations and trends, we do not have an instrument that tells us how much change is due to humans and how much to Mother Nature. Measuring the temperature change over long time periods is difficult enough, but we do not have a thermometer that says why these changes occur.
We cannot appeal to direct evidence for the cause of change, so we argue.
The real climate system is so massively complex we do not have the ability to test global-size theories in a laboratory. Without this ability, we tend to travel all sorts of other avenues to confirm what are essentially our unprovable views about climate. These avenues tend to comfort our souls because we crave certainty over ambiguity.
It is a fundamental characteristic of the scientific method and, therefore, of the confidence we have in our theories, that when we finally understand a system, we are able to predict its behavior.
One avenue of inquiry is computer simulation. If a system’s important details can be represented properly in a computer model, predictions can be accurate and therefore valuable.
My local supermarket can predict with great skill what I am going to buy, thanks to the information-gathering system now utilized and my boring eating habits. Unfortunately, even the most advanced set of climate-model simulations does not deliver much in the way of certainty.
For example, I analyzed the tropical atmospheric temperature change in 102 of the latest climate-model simulations covering the past 35 years. The temperature of this region is a key target variable because it is tied directly to the response to extra greenhouse gases in models. If greenhouse gases are warming the Earth, this is the first place to look.
All 102 model runs overshot the actual temperature change on average by a factor of three. Not only does this tell us we don’t have a good grasp on the way climate varies, but the fact that all simulations overcooked the atmosphere means there is probably a warm bias built into the basic theory — the same theory we’ve been told is “settled science.”
To me, being off by a factor of three doesn’t qualify as “settled.”
As important as models can be for problems like this, it is clear we have a long way to go. And it is troubling that current policy is being based on these computer models, none of which has been validated by a formalized, independent Red Team analysis. (Congress, EPA: Are you listening?)
Others might look to certain climate anomalies and convince themselves that humans are the cause. I often hear claims that extreme weather is getting worse. Now, here we do have direct evidence to check. Whether it’s tornadoes (no change over the past 60 years), hurricanes (no changes over the past 120 years) or droughts and heat waves (not as bad as they were during the past 1,000 years), the evidence doesn’t support those claims. So, we argue.
Without direct evidence and with poor model predictability, what other avenues are available to us? This is where things get messy because we are humans, and humans tend to select those avenues that confirm their biases. (It seems to me that the less direct evidence there is for a position, the more passion is applied and the more certainty is claimed.)
One avenue many folks tend to latch onto is the self-selected “authority.” Once selected, this “authority” does the thinking for them, not realizing that this “authority” doesn’t have any more direct evidence than they do.
Other avenues follow a different path: Without direct evidence, folks start with their core beliefs (be they political, social or religious) and extrapolate an answer to climate change from there. That’s scary.
Then, there is that time-honored, media-approved, headline-grabbing source of truth — the opinion poll. The poll can be of scientists, nonscientists, the man on the street, anyone with a smartphone or groundhogs. If no one (not even an esteemed scientific organization) has direct evidence to substantiate any claim of the impact of greenhouse gases on climate, what would an opinion poll provide besides entertainment or (worse) justification for one’s agenda?
This polling tack is relatively clever. Without direct evidence to prove or refute the claims of a climate poll, the poll becomes the popular avenue for supporting whatever claims are being made. With enough attention, a poll’s climate claim morphs into “settled science.”
So we argue even more.
Finally, what to do about climate change is not a scientific question; it is a moral question: Is there value in enhancing the quality and length of human life?
If one believes greenhouse gases will cause terrible climate problems, then stopping their release from sources of carbon-burning energy means energy costs will skyrocket.
However, the length and quality of human life is directly proportional to the availability of affordable energy, which today is about 85 percent carbon-based. The truth is, carbon emissions will continue to rise no matter what the U.S. does, because most of the world has already answered the real question — that argument is settled.
Should we study new sources of energy? Absolutely.
And when they become safe and affordable, they could be ready for deployment. Until then, I’d rather see my five grandchildren have the opportunity to accumulate wealth, enabled by affordable energy, rather than be made poorer and thus less able to face whatever vagaries the world and the climate might throw at them in the future.
This is much more than a murky scientific issue and why the stakes, and thus passions, can be so high — and why we argue.
John R. Christy is a professor of atmospheric science at the University of Alabama in Huntsville and Alabama state climatologist. Readers may write to him at firstname.lastname@example.org. He wrote this for The (Fredericksburg, Va.) Free Lance-Star.