Lotta sent me a link to a fascinating UK documentary that claims that the generally accepted relationship between CO2 and global warming (i.e., CO2 causes global warming) is actually backwards from what the data show. According to the scientists interviewed in the program, Antarctic ice core data show a lag between changes in global temperature and the amount of CO2 in the atmosphere. Throughout history, CO2 levels have increased decades after the planetary temperature has risen. This suggests that global warming leads to more CO2 in the atmosphere, not the other way around.
So if global warming isn't caused by CO2, what is the cause? The answer suggested in the documentary has to do with solar activity, solar wind, cosmic rays, cloud formation and the greenhouse effect caused by water vapor. Take a look; I found the data persuasive.
The documentary doesn't claim that global warming isn't happening; on the contrary, it claims that global warming and cooling are natural phenomena that have happened in cycles for as far back in time as we can see in the data. The point is that a lot of human effort is being expended reducing emissions of CO2, a molecule that the show's creators claim plays a comparatively miniscule role in climate change. It makes me wonder if the priorities of environmentally-conscious people around the world are a bit out of whack.
Perhaps we should instead concentrate on reducing the sorts of pollution that cause demonstrable harm to people, such as soot, pesticides, and runoff from mines. Also, even if we accept that the current trend of global warming is a serious problem, reducing CO2 emissions might not be the best way to address the problem. Perhaps we should find other more effective ways to address climate change. Some scientists have suggested deliberately seeding the upper atmosphere with dust to reduce the amount of sunlight that reaches the surface. The idea is that this would cause cooling similar to what is seen after large volcanic eruptions.
Another question is why so many people accept without question an explanation of global warming that is based on a backwards interpretation of the data. Is this just another example of groupthink?