by Judith Curry
The most savage controversies are those as to which there is no good evidence either way. -Bertrand Russell
As Science magazine observed in a March 30, 1990, editorial:
“Virtually everyone, children included, is concerned about global climate change and especially about the greenhouse effect. They have learned of increases in carbon dioxide. They have been told repeatedly that temperatures will increase 9’F. Political pressure is mounting to take action regardless of cost, and to take action now.”
This much is familiar to any observer within reach of the popular media. But what follows is not : “But how good is the evidence, and how likely is substantial global warming? When might it happen”? Applying the customary standards of scientific inquiry, one must conclude that there has been more hype than solid facts. Modeling of global climate is largely concentrated on examining effects of doubling the atmospheric content of greenhouse gases. As might he expected, the answers they get are functions of the models they employ. The spread is from 1. 5′ to 5’C; that is, there is great uncertainty. If one examines the subject, one finds virtually unanimous agreement that the models are deficient.
Where Science speaks of conflicting studies and ambiguous results, the popularizers of the greenhouse effect deliver dire warnings with the utmost certitude. In the name of the greenhouse effect, some environmentalists are demanding a 30 percent rollback in C02 emissions by the year 2000. They seem oblivious to the enormity of what they are demanding: a war on that most elemental of human discoveries-fire itself.
Why this enormous gap between what is known and what is urged?
Why It’s Not So Simple
THE ATMOSPHERE is among the earth’s most complex dynamic systems: subtle in its chemistry, chaotic in its flow. It interacts with everything from the solar wind to the deep oceans. It is subject to insults great and small, brief and enduring, from men and meteorites, volcanoes and termites, wildfires and algal blooms–a list without end.
The atmospheric sciences presently lie in limbo between the Newtonian rigor of classical physics and the realm of the undecidible. It is an uncomfortable time. The range of sincere expert opinion broadens with the complexity of the subject at issue. And at the interdisciplinary extreme–global climate expertise itself dissolves in that most universal of solvents, the theory of complexity.
If there were world enough and time, individual atmospheric scientists might achieve a combination of physical and geometric intuition approaching certain knowledge of how the earth will respond in the long run to human intervention. But in practice such polymathy scarcely exists- scientists are reeling in shock at the information explosion they’ve touched off.
We have as well another major problem. While we have indeed driven carbon dioxide above the historical (hundred-thousand-year) range of its recorded natural fluctuation by about 20 percent (70 parts per million), we have a rather feeble understanding of the paramount greenhouse gas: water vapor. Its clouds fill a tenth of the sky. ts atmospheric concentration is so vastly greater than that of C02 as to obscure its effect.
Tracking the Invisible Man
As a window for laymen to peer through, Global Change and Our Common Future, published in 1989 by National Academy Press, affords a startling contrast. At one end of the spectrum lies the rhetoric of uncertainty that dominates the hard sciences in the study of global change.
It is exemplified by the admission that it will take decades for a clear greenhouse signal to emerge from the noise of climatic variation-witness the dust-bowl drought of the 1930s and the abnormally high Great Lakes water levels of the 1980s-and by the confession that it will take 500 times more computer power to realistically model the course of the quarter-century to come. As one participant in the forum, which produced Global Change, J.D. Mahlman, noted, “Until such decadal-scale fluctuations are understood or are predictable, it will remain difficult to diagnose the specific signals of permanent climate change as they evolve. “
At the other end of the spectrum lies the rhetoric of extinction- life scientists confidently predicting the climate-driven disappearance of species over the next fifty years.
By the volume’s end, it is clear on which side Senator Albert Gore has enlisted: “My purpose is to sound an alarm, loudly and clearly, of imminent and grave danger, and to describe a strategy for confronting this crisis … the horrendous prospect of an ecological collapse. ”
So too, scientific perceptions of both where the world is, and the timing of its rendezvous with climatic change, are still in part very much a matter of taste. As is the question of whether scientists from disciplines unrelated to the atmosphere should lend their authority to the promotion of policies that might not prevail on the objective strength–or empirical weakness–of the available evidence. It is a prerogative of the manifesto-writing classes to dragoon as many members as they can of the National Academy of Sciences into signing them (a task too often easier than getting them read).
But the resulting embarras de richesses can he a problem when the signatories outnumber the real experts in the field. The Union of Concerned Scientists got a majority of the membership to sign a declaration calling for a substantial reduction in global C02 emissions by the year 2000. Some members (notably MIT atmospheric physicist Richard Lindzen) were appalled and said so, but they failed to make it onto prime-time television.
A DISTURBING reality confronts us: A the deliberate creation of a double standard, with one set of facts for internal scientific discourse and another for public consumption. On C02, some have cast objectivity aside and openly made common cause with the eco-politicians. But this pathology of the sociology of science is not without a remedy. For the power of television to project unchallengeable images of environmental quality, real or imagined, is utterly undone when the public achieves even a minimal level of quantitative understanding; numeracy and skepticism go hand in hand.
In the absence of numbers candidly conveyed, it is all too easy to transmute supposedly quantitative scientific “facts” about the present into a qualitative legal fiction about the future.
Clearly, a sharp-toothed carnivore is on the prowl. But we’ve yet to see a full-grown specimen. Are we dealing with Snoopy or Cerberus? It’s hard to tell- it’s only just a foundling pup, and the question of its diet remains to he wrestled with–it might grow into either. But grow it will–slowly, and for a long while undetectably. One of these centuries, we’re going to have a real dog in our front yard. But what kind? And when? An interdisciplinary consensus on the magnitude of the “greenhouse effect” and its impact on sea levels in the next century won’t come cheap-or soon.
Nobody knows if the synergy of all the ill-defined feedbacks will coincide with high-side outcomes of the many inputs that global systems models require. So some will invoke the presumed prudence of assuming the worst. For others, there is Murphy’s Second Law: if everything must go wrong, don’t bet on it.
Turning Up the Heat
Politically, I counsel constant vigilance. The salvation of the world affords an enchanting pretext for those predisposed to societal intervention. They have already raised the abolitionist banner, pointing to the prospect of Bangladesh awash and water skiing down the Mall to the Capitol–a prospect no more likely in my lifetime than nothing happening.
My personal expectation–and I reserve the right to change my mind if the evidence does–runs more to centimeter-per-year rises in sea level and a lot more climatic variability than actual temperature rise in that lifetime.
So there may indeed be a solution to the profound uncertainty that engenders reluctance when we are offered insurance against C02 bracket creep-at a trillion-dollar premium. Consider a double Scots Verdict: even if the verdict on global warming is not proven, we could still save a bundle of hard cash if a canny enough energy policy can be found.
And better too that cooler heads than those that dominate the hot media prevail in informing the Congress and the electorate. For this much is certain: science needs to see the illumination of today’s hot-tempered environmental policy debates. If light is to prevail over heat, many will have to simmer down and reflect they have lately been doing or counseling.
If candor prevails, climate professionals will realize once again that laymen too can recognize cant when they hear it and cartoons when they see them. Scientists would do well to recall that insight’s inevitable corollary-the neutrality of scientific institutions must first exist if it is to he respected.
Whether the trial of Galileo or the tyranny of Lysenko, at all times and in all polities, science politicized is science betrayed.
Think back to 1990 – as for moi, a recent Ph.D. graduate, I was aware of the issue but not paying much attention. I didn’t start paying much attention to politics and the broader scientific issues until 2005 (courtesy of the hurricanes and global warming wars).
I suspect that Seitz’s 1990 perspective was shared by a substantial majority of atmospheric scientists at the time. At that time, there was a relatively small number of scientists who were publicly sounding the alarm – Jim Hansen, Steve Schneider and John Houghton come to mind.
I excerpted about 20% of Seitz’s essay – points that generally remain valid today, IMO. Ironically, making such statements today would immediately classify you as a ‘denier’.
But we know so much more now than we did in 1990, right? Well, the range for climate sensitivity remains pretty much the same. The complexity of our understanding of the climate system has increased, with more complex climate models. But the science has become far more politicized, raising a host of questions about implicit and explicit biases in the science. And we still don’t have a good way to separate unforced (internal) from forced climate variability. The overall lack of policy relevant progress has been caused by the politicization of the science, and the focus on human caused climate change (neglecting natural causes of climate variability).
And finally, some reflections on Seitz’s current role in the climate debate. Seitz continues to publish some interesting essays, notably Knowing the Unknowns. He also blogs on climate issues vvatsupwiththat, which as far as I can tell belongs to the Sou Boudanga school of climate blogging (although I find Seitz’s blog articles pretty incoherent). I’ll ping Seitz on twitter to see if he will stop by to discuss.