A climate scientist tells us that the science is not at all settled

The ABC and the media generally report climate stories as though what they are telling us is the unvarnished truth, and when anyone objects, the response is that the science is settled, or that 97 per cent of scientists agree about global warming. The sceptic or seeker after truth is portrayed as a denier facing the whole of organised science. That’s not the way it really is, at all, but it’s often hard to find, outside the well-known sceptical group, a scientist who offers publicly what I would call a ‘realist’ view. But I came across one the other day, and I thought it would be worthwhile to set out what he says about the so-called settled science of climate.

His name is John Christy. He is Distinguished Professor of Atmospheric Science at the University of Alabama at Huntsville in the USA, and he is also that State’s Climatologist. A third count in his favour is that he is responsible for one of the main temperature datasets that everyone uses, that of the University of Alabama at Huntsville (UAH). Christy has won a number of awards and honours, has testified before Congress, written editorials for the New York Times, and has been an expert reviewer for the IPCC.

The paragraphs that follow, re-ordered by me, seem to me crystal-clear, simply expressed, and most persuasive. He wrote them for a local newspaper in Virginia.

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.

Christy goes on to dispute that climate models are of much use.

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.”

Worse, he continues, none of the models has been validated by an independent team. People go on about extreme weather, but Christy points out that the evidence simply doesn’t support the claim that extreme weather is getting worse and that the cause must be carbon dioxide.

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.)

What about the authority of bodies like scientific academies and the IPCC? Some people, he says, latch onto [such a] 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.

He finishes with a reminder.

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. 

Christy’s little essay is one of the best I have read on this subject. Would Professor Flannery, or Professor Steffen, like to provide his own counter?