Qing-Bin Lu, a professor of physics and astronomy at Waterloo, says "global warming" lasted from 1950 to 2000; and we are now in a cooling period. This already suggests no real correlation with man-made CO2, which has been increasing steadily since about 1850. He says in fact that when warming occurred, it was caused by a combination of chlorofluorocarbons (CFCs) and cosmic rays. Production of CFCs has gone down dramatically since about 2000, which was the first year that developed countries produced no new CFCs at all. Dr. Lu was intending to explore the relationship between CFCs and ozone loss or "the hole in the ozone layer," but he ended up arriving at findings about temperature and climate.
His work is peer-reviewed in a peer-reviewed journal (Physics Reports) with lots of peers reviewing it. In fact, it may even be sprinkled with fairy dust.
I think for a lay person the main question is: is there some doubt about the science that underlies the recommendations to spend billions or trillions reducing CO2 emissions?