Global Warming May Have Killed the Dinosaurs 269
The Fun Guy sent in a link to the American Society for Microbiology site, your leading news source for everything between nano and macro. The site is featuring a story about new research into the KT barrier extinction: the period in history where the dinosaurs went extinct, along with a number of other families of species. For a number of years scientists have theorized that an impact on the Yucatan peninsula was responsible for the species crash, but microbiological examination of marine organisms of the time indicate life persisted for another 300,000 years after the 'Chicxulub impact'. The researchers at Princeton who made this discovery theorize that global warming caused by a volcanic eruption in India is a more likely culprit for the world-wide devastation. The article generalizes that there is no 'smoking gun' for this event, and further research is required.
What I have always wondered about... (Score:4, Informative)
http://www.unb.ca/passc/ImpactDatabase/CIDiameter
Wikipedia blurbs on the two largest (as usual, do more research to verify if interested:)
http://en.wikipedia.org/wiki/Vredefort_crater [wikipedia.org]
http://en.wikipedia.org/wiki/Sudbury_Basin [wikipedia.org]
There are also questions about a possible crater in Antarctica, but it's too new an announcement to know if the features observed are actually impact related: http://researchnews.osu.edu/archive/erthboom.htm [osu.edu]
My question is, why would the Chicxulub event have been so uniquely deadly?
I suppose one possible scenario is a double (or more) sucker punch of large impact followed by volcanic activity and/or other factors that happened to hit while the Earth was still recovering from the impact. Of course, that's a bit complex for a spectacular headline.
I hope work continues on this - it's a fascinating insight into our environment and might be useful in knowing how to safeguard ourselves against changes in the future.
Actually, it says both (Score:3, Informative)
Later, global cooling wiped out the ones that were left.
From what they can tell, the Chicxulub impact occured too early to have triggered the global cooling.
Re:What caused it? (Score:3, Informative)
The issue here is that we might be warming the Earth artificially already, so when the natural process kicks in on top of our "contribution" we all could be royally screwed.
We are in fact supposed to be living in an Ice Age at the moment, so the "natural" warming ain't even here yet!
On the positive side, perhaps 75 million years in the future some giant cockroaches could use our liquified remains to fuel the SUVs!
Re:Well, THERE'S the problem! (Score:3, Informative)
Every time a global warming story comes up, lots of readers throw out their own unsubstantiated (or more usually debunked) theories, without bothering with basic fact checking. Here, the parent is 'certainly interested' in geologic CO2 fluxes, but can't be bothered to search. Are geological CO2 fluxes being measured? Yes. It's called Wikipedia, people.
Sorry. But if someone throws out solar fluctuations as the primary reason for current warming one more time, I'm going to be very, very cross. Do some research.
Start here [wikipedia.org]
Carbon flux- humans have thrown the net flux out of whack [wikipedia.org]
The ocean is a carbon sink, thanks to us [wikipedia.org]
Here's the carbon cycle. Lots of big fluxes, but we've tipped the balance [nasa.gov]
Re:Iridium layer (Score:3, Informative)
Re:Well, THERE'S the problem! (Score:3, Informative)
Then read this [nasa.gov]. Surprise! The volcano argument is lame.
Your post is exactly what I am talking about [slashdot.org]; I should have teed off on you instead of that other guy. You have a belief (loosely stated as my poop can't possibly be as stinky as moose poop) and have found support for it with a number that is, by any sane reading of the data, wrong. There's plenty of holes to poke in climate change science, but where the increased atmospheric and oceanic carbon is coming from ain't one of them.