[fella]

Mark Purdey has done a lot of study on this and has come up with conclusions along the same lines. It takes awhile to go through his site but it as a lot of good information.

[Lil'freeper]

Thank you for posting Purdey's link- you beat me to it. Although he'll strike many here as an environmentalist wacko, he's truly an independent researcher. Here are two essays that summarize his thesis: part 1 and part 2. Food for thought at very least.