Climate Change and Comets
This is the opening to a terrific story by Rex Dalton in Miller-McCune:
It seemed like such an elegant answer to an age-old mystery: the disappearance of what are arguably North America’s first people. A speeding comet nearly 13,000 years ago was the culprit, the theory goes, spraying ice and rocks across the continent, killing the Clovis people and the mammoths they fed on, and plunging the region into a deep chill. The idea so captivated the public that three movies describing the catastrophe were produced.
But now, four years after the purportedly supportive evidence was reported, a host of scientific authorities systematically have made the case that the comet theory is “bogus.” Researchers from multiple scientific fields are calling the theory one of the most misguided ideas in the history of modern archaeology, which begs for an independent review so an accurate record is reflected in the literature.
(Real Climate was dubious several years ago.)
In his piece, Dalton goes on to chronicle the hubris of the comet proponents and notes:
Such intransigence has been seen before in other cases of grand scientific claims. Sometimes those theories were based on data irregularities. Other times, the proponents succumbed to self-delusion. But typically, advocates become so invested in their ideas they can’t publicly acknowledge error.
The controversy will perhaps resonate beyond rarified science circles “because it involves the politically sensitive issue of a climate shift,” Dalton writes.
He then turns to a famous climate expert:
“It does feed distrust in science,” says Wallace Broecker, a geochemist at Columbia University and an international dean of climate research. “Those who don’t believe in human-produced global warming grab onto it.”
In fact such episodes show the self correcting nature of science at work. Of course it may go slower than many people would have expected, but still.
As with the climate system, there are different time scales involved: A bogus idea comes very fast and goes a lot slower, but doens’t typically last very long compared to typical timescales of scientific knowledge building.
Also, it’s very true that “typically, advocates become so invested in their ideas they can’t publicly acknowledge error.”
Cosmic rays, iris, etc: These ideas are intimately connected with their originators/popularizers, and they will never back down from it once their personality is so stronlgy connected with their pet pieve theory. Of course some may say the same of “AGW”, but I don’t think that supposition would hold: The mainstream knowledge of climate change has steadily built up over time and gotten stronger rather than weaker, over multiple decades (spanning 1 1/2 century even). That is not a sign of a bogus theory; to the contrary.
I’m 100% with Bart on this, and while I don’t often disagree with Wally on this one I can’t see that he’s right. The comet proponents had a wild idea but one which they were able to argue for with falsifiable though rather speculative methods of science. They got their wild idea published, despite (or because of) the fact that it was iconoclastic vis a vis the glacial drainage theory. And then science got into it and showed it wrong, all in a matter of a few years.
The fact that the basic theory behind anthropogenic global warming has been around for over a hundred years (and in quite mature form since 1980), that few of the self-professed skeptics are able to couch their wild ideas in a sufficiently scientifically credible way to get them published in respectable journals, and that nobody has managed in all this time to overturn the central premises underpinning the prediction of risks caused by CO2 emissions — all that should roundly build faith that the scientific enterprise is working soundly and reliably when it comes to climate change.
When a hypothesis is put forth to explain a climate change event (past or present), deniers will use that to claim manmade activities aren’t causing warming. Climate, after all, has changed before without SUVs. When such a hypothesis is later refuted, deniers will use that to claim science can’t be trusted, and therefore manmade activities are not causing warming.
+1 to all above.
If competing theories are tested, and some found to be false, opponents of action will say, ‘look, the scientists don’t know whats going on!’; if there were no competing theories they would say, ‘look, the scientists are being dogmatic and not considering opposing theories!’ It will always be thus. Better understanding of the scientific endeavor is all I can see that would help, though not anytime soon.