The proponents of catatrophic global warming are taking some serious hits lately. One of the basic concepts behind the global warming hypothesis is that the concentration of carbon dioxide in the atmosphere was constant up until the start of the industrial age about a century ago. The increase in atmospheric carbon dioxide since then was the reason for the purported 1 F average temperature increase over the last century. (The reason for a simliar average temperature increase over ninteenth century was not explained, nor were the temperature fluctuations in the twentieth century that did not comport with the steady increase in carbon dioxide in the atmosphere.) Now researchers are looking at direct measurements of atmospheric carbon dioxide concentrations made 150 to 200 years ago. Many of these measurements indicate levels that are higher than those seen today. It turns out that the IPCC disregarded over 90% of the old data because it didn't match the assumption that carbon dioxide levels were constant prior to the industrial age. It is curious that the IPCC acknowledged that carbon dioxide levels had varied widely over the history of Earth, and that some such as Al Gore had argued that the large increases in Earth's temperature in the past were caused by the increase in carbon dioxide even though it was clear that the temperature increases preceded the carbon dioxide increases. There is also recent work that casts doubt on the cloud data used in the Global Circulation Models. The GCMs do a poor job of predicting cloud cover, so that becomes an input parameter. Clouds obviously have a lot to do with temperature, so an error in cloud action makes the computer simulation invalid. It becomes a classic case of what in the computer analysis world is called GIGO (Garbage in, garbage out).