I consider ALL stories of human caused global warming to be crackpot.....some are more crackpot than others though.
There are three kinds of greenhouse gases: 1) water vapor - which is by far the most common, and natural; 2) carbon dioxide; and 3) methane. The “man-made” global warming morons focus on CO2, which is present in the atmosphere to the extent of 380 parts per million. Horrors! This is up from 320 ppm about 50 years ago, and they say it is all due to evil capitalists driving cars and burning wood in their ski condo fireplaces. The UN’s Kyoto Agreement and legislation proposed by socialists (both parties) in Congress will of course save the world.
The fact is, no one knows if the 60 ppm increase is all due to human activity. And know one knows if it is really a threat. More than likely, it is a minor blip compared to the activity of the sun, and its impact on our climate. What is known, is that normal precipitation (i.e., weather) on earth offsets the warming effect of greenhouse gases, making the earth very comfortable, thank you. Normal weather acts as a thermostat vs. normal water vapor.
I suggest reading “Climate Confusion” by Roy W. Spencer, and also “Unstoppable Global Warming -Every 1,500 Years” by Fred Singer & Dennis Avery. The first is superb. The second presents a theory that the sun’s cycles of activity are the main cause of cooling and warming periods on earth, happening about every 1,500 years.