Friday, March 05, 2010

Giant Rock Vs Volcanos - Round Two

By the looks of it another great scientific row is brewing. Last year I posted on reports by scientists that the extinction of the (non avian) dinosaurs was primarily caused by volcanic eruptions rather than a giant asteroid as previously claimed. As you might imagine, this was pretty controversial and now a review paper authored by a dream team of 41 researchers from 12 nations has appeared defending the original theory; in fact it goes as far as to say that the science is effectively settled. Much of it is a simple restatement of the original hypothesis but it does attempt to counter a number of the claims made by Gerta Keller and her team. As you might expect the ‘giant rock sceptics’ aren’t convinced.

"It's the same old story from them," says Norman MacLeod of the Natural History Museum in London, referring to the team that wrote the new paper. "The authors conveniently forget to mention critical data."

….MacLeod and another prominent doubter, Gerta Keller of Princeton University, don't dispute that a colossal space rock hit the Earth roughly 65 million years ago. And whether or not that led to the demise of the dinosaurs, new research is painting an increasingly detailed picture of the hellish conditions after the asteroid's arrival. The authors of the new study say that more than 60 percent of species went extinct, including most dinosaurs. MacLeod, though, says that dinosaurs were in decline for millions of years before the asteroid hit. He also wonders why, if the asteroid strike was such a doomsday event, some classes of species survived and even thrived. Keller questions even more basic claims, such as the dating of the asteroid strike. She argues that the Chicxulub rock hammered Earth hundreds of thousands of years before the mass extinctions shown in the fossil record. Just such arguments -- and media coverage of them -- are what prompted the scientists to publish their new paper, Goldin says.

After ignoring Keller and other skeptics for many years, the pro-crater forces got so frustrated that they decided to put all the evidence together.
"It is almost impossible to change the skeptics' minds," Goldin concedes. "But we hope we can communicate to the scientific community and the public that this impact-induced environmental catastrophe did happen."

I have to say I’m a giant space rock man myself, but I think there is a little of the ‘grandstanding’ about releasing a paper of ‘consensus science’ with no new findings and trying to present it as the final word. As Guardian user Arbuthnott says:

Let's hope that this is not a model for our ongoing treatment of AGW:

* Multiple competing theories, which appear to shuffle in prominence according to fashion (global warming has recently become popular for many or all of the other major extinction events and is a strong contender for this one)

* Reputable panel works for 20 years to come up with a definitive "consensus view", which now favours the "nuclear winter" mechanism for the extinction event

* An important competing claimed explanation published with considerable fanfare immediately beforehand, based on global warming from lava outflows

* By its conclusion (I have not read the report)), the published "official" solution appears to ignore the "double" iridium layer phenomenon, and "Shiva"

* Without the apparently slightly later impact of "Shiva", the crater of which is visible in the ocean off what is now Mumbai, India, there is a problem of timing, in that the dinosaurs appear to have been slow on the uptake and died as much as several hundred thousand years after the Chicxulub impact.
Still, I am glad that all this is now officially settled and we can go back to worrying about other things.

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Karl said...

Volcanoes or Asteroids? Huh, personally I like this theory better.

It has got more style, more drama; know what I am saying?

Well, within all seriousness I tend to lean towards giant asteroid killed the dinosaurs.

Jamie said...

Why not both? Deccan traps make life grim for the dinosaurs, big rock finishes them off.

Jim S. said...

I think the dinosaurs were wiped out by a giant whipped-cream pie, as evidenced by a worldwide layer of whipped cream marking the Creosote-Tutelary boundary (source).