At the 21 minute mark of this video of his Becker-Friedman Institute talk, Bill Nordhaus begins to discuss the impacts of climate change.  He stresses three impacts while emphasizing how difficult it is to predict future adaptation.  Overall, he appears to be an optimist but acknowledges the significant uncertainty!

1. The impact on agriculture ---- he points to the IPCC report and presents a nuanced view of the ability of farmers to adapt.  He presents a graph that farmers can take the heat with losing much output. He is highly optimistic about the ability of the farmers to adapt and slightly mocks the IPCC's doom and gloom.

2.   Species extinction --- here he is more pessimistic.  He notes that ecologists predict a major increase in extinction over the next 100 years relative to the previous 500 years.   For example, many snails are going to have trouble adapting to the heat.   Should we care?  Would Darwin care?

3.  Tipping points and catastrophic effects --- global effects such as melting of the Greenland ice caps and ocean acidification.   Nordhaus points out that his house would flood.   He argues that science finds that the melting of Greenland will take hundreds of years even at a 6 degree Celsius to melt.

At the 48th minute, Nordhaus says some very smart stuff regarding adaptation that Julian Simon and I both applaud.  He claims that adaptation is difficult to predict and then some guy at the 49th minute asks whether it is possible that "no adaptation" will occur and Nordhaus shoots him down.