AFP: Global warming exists and is unquestionably due to human activity, France’s Academy of Science said in a report published Thursday and written by 120 scientists from France and abroad. “Several independent indicators show an increase in global warming from 1975 to 2003. This increase is mainly due to the increase in the concentration of carbon dioxide,” the academy said in conclusion to the report. “The increase in carbon dioxide, and to a lesser degree other greenhouse gases, is unquestionably…