It was back around 2005. I’ve been looking for the research paper. It used to be online but can’t find it on google now. I did find a few references in articles that refuted similar conclusions. Funny how the refutations are searchable but not the actual paper itself. It appears to have been scrubbed. Welcome to 1984.
Thanks for checking. I found an article from about the same time period. It said that people had refuted the finding but how. Not surprising that a finding would destroy the biggest source of climate funding and an excuse for total govt control would be “refuted”.