To hear Dave Dahl tell it, climate change has no connection to human activity, notably the staggering increase in the past two centuries in atmospheric greenhouse gasses.

Dahl's only authority for his thesis that solar cycles are “the main driving force” of what he considers "climate change" is NASA -- hardly authoritative after eight years of an administration whose denial of anthropogenic (human-caused) planetary warming has been a policy and scientific scandal.

Pieces like Dahl's do the public a profound disservice, by distracting us from the hard choices that lie ahead. The fact of human-caused global warming is no longer a scientific controversy. Both John McCain and Barak Obama have addressed it on the campaign trail and a major feature of the next Administration will be federal legislation to curb emissions from industrial and power-generation sources.

Dahl should stick to what he knows, and does quite well: tomorrow's weather forecast.

I agree with the first comment. In 1983, I attended a University class that was required for fourth year Environmental Studies Majors. Among the many teachers were two that had worked at NASA. Global Warming was covered in detail and the major emphasis was upon "man's activities" and the need to curb fossil fuel use, pollution, deforestation and on and on. It is now 2008, gases are seeping through the melting Permafrost, and all Dave can do is sway people away from learning about the crisis we now face.