I value his views particularly as a Senior Scientist and pleased of his reasoning on this issue having held simular views for many years, mind you I haven't done the research he has.
Regardless of global warming (or cooling) I still think it is prudent, and just plain common sense, to look after our environment and minimize our impact. So energy efficiency, reducing pollution, reducing the burning of fossil fuels, preservation of forests and natural habitats, are all aims I support and think governments and companies should be doing more to support.
For one thing temperature data has been cherry picked, massaged, and politically interpreted by some people to support their global warming hypothesis.
When I look at broader data sets and raw data, without fudging selected data and omitting other data, you find there is no warming trend, and most likely there has been a cooling trend over the past 5-10 years. Another thing too is that our life on earth depends upon a greenhouse effect of about +33°C, without which the global average temperature would be -18°C instead of the +16°C it currently is.
I think many of the scientists involved have allowed their ambition (for career, doing good, or profit) to cloud their judgment, much like Shakespeare's Macbeth. Sadly, I think it makes all scientists and science look bad and undermines motivation to reduce emissions, including CO2, reduce waste, and take better care of the environment.
- http://www.ruf.rice.edu/~leeman/GeoColumn.gifClimate change Graph