Based on what I've read, ecosystems can adapt to a maximum rate of temperature change of about 2 C per century. That's about the midrange of good estimates for what will happen next century, even from noted skeptics. The Nature article indicates that ecosystem changes are observable due to the warming which has already occurred in the past 100-150 years, most notably the more rapid warming of the last 30 years. That doesn't mean ecosystems will collapse or that major extinctions will ensue (and there are other causes of extinctions that are probably more extensive and also more preventable, such as deforestation).
One of my favorite resouces for info on global warming is the Science & Environmental Policy Project
It is headed up by Dr. S. Fred Singer. A man that has repeatedly challenged Algore to debate global warming. Algore refuses. Algore also cancelled an apperance on Larry King Live to discuss global warming when he learned that Dr. Singer was going to be on the show with him. Algore later returned to do the show alone.
Human (read American) caused global warming is a scam.