Finally confirmed: An asteroid wiped out the dinosaurs

No, you became more certain that an asteroid hit a certain place to within a 11,000 year range. Title is false. From the actual paper's abstract:

> The Chicxulub impact likely triggered a state shift of ecosystems already under near-critical stress.

So this confirms that one thing (likely) happened while other things were happening. I can think of other things that were happening that would put the ecosystem into near-critical stress:

- For one thing, the Deccan traps were spewing crazy huge volumes of noxious material into the atmosphere for about 30,000 years.

- For another, the supercontinent cycle was in a period of orogeny and likely caused an icehouse climate. There would be lower diversity in "bottom rung" niches, which combined with the hazardous effect of global volcanic eruptions for 30,000 years could very likely destabilize the food chain. This bodes poorly for large megafauna which reproduce relatively infrequently and require large amounts of specific foods to meet their nutrition requirements.[1]

There was a large confluence of factors and it makes intuitive sense that, just as the abstract says, a large impact could be the proverbial straw on the proverbial camel's back. I have no doubt the asteroid was important.

But this Roland Emmerich disaster movie interpretation of geology isn't nearly the whole picture. My best guess as to why we latch onto this hypothesis, aside from how admittedly awesome it sounds, is because it's hard for us to accept that this kind of change is gradual and can sneak up on us. It takes the matter out of our hands and alleviates us from certain responsibilities. Clearly something sudden must happen because otherwise we totally have this under control, right? But that sort of waxing is not terribly useful.

[1] (Update). Note how avian dinosaurs survived, but plesiosaurs did not. The air was apparently survivable enough, but the near-shore ecosystem - which would be adversely affected by the reduction in coastlines from a supercontinent aggregation - lost its large lumbering members sitting atop the precarious food chain. None of this constitutes evidence, but I think my wild-ass guess is at least as valid as any other wild-ass guess, consensus or not.

See a current submission to HN

http://news.ycombinator.com/item?id=5187709

for a more nuanced discussion that is not a rehashed press release, but an edited long-form article by an experienced writer on the topic.

When I read the title, I was also shocked by the word 'confirmed.' Any kind of explanation about dinosaurs explanation should be a theory. We can say 'the new evidence provided support for a theory' but cannot say 'the new evidence confirmed that the theory is the truth.'

I was hoping for some more evidence of causation. The new research is still circumstantial, in that before it was the assumptive cause because the impact was dated to within ~1 million years of the extinction event, and now it's even more assumed to be the cause because it has been dated to within ~11,000 years of the extinction event.

Where was the line drawn for it to be "confirmed"? Is circumstantial evidence the best we can do?

Perhaps science changed in the last decade, but when I worked on my PhD words like "confirmed" and "definitely" were frowned upon.

Frequent asteroid impacts lend credence to the Doomsday Argument [1], which, simply put, argues that it is unlikely that the human race will be long lived, simply because it is growing so fast. According to the DA, there is a 95% chance of extinction within 9,120 years.

[1] http://en.wikipedia.org/wiki/Doomsday_argument

I have a tough time believing the word "confirmed" when the scientists behind the study use the words "likely triggered".