Not so fast. If you read other articles from the same site you find that:
1. "Silver Bullet" theories like asteroid impacts are not generally associated with mass extinctions.
2. What may have caused most mass extinction events is "sick earth syndrome" which they compared to global warming.
3. Therefore if we continue to drive our SUV's around we will generate a new "sick earth" event which will cause a mass extinction.
So we can safely take all the money we are spending on tracking asteroids and give it to Al Gore so he can continue to generate hot wind.
“Not so fast. If you read other articles from the same site you find that ... “
The article I posted was just one at the Science News source that pointed to an asteroid/comet impact as being the source of the extinctions and not humans ...
1. Six North American Sites Hold 12,900-year-old Nanodiamond-rich Soil http://www.sciencedaily.com/releases/2009/01/090101172136.htm
2. Extraterrestrial Impact Likely Source Of Sudden Ice Age Extinctions - http://www.sciencedaily.com/releases/2007/09/070924172959.htm
3. Did A Comet Hit Great Lakes Region, Fragment Human Populations, 12,900 Years Ago? - http://www.sciencedaily.com/releases/2007/05/070523094009.htm
4. Exploding Asteroid Theory Strengthened By New Evidence Located In Ohio, Indiana - http://www.sciencedaily.com/releases/2008/07/080702160950.htm
George