I don't discount the previous heating & cooling cycles, what I do see is how RAPID it is happening. The last warming period took some 10,000 years to equal what has now happened in 150 years. I live near the large icefields(Colombia icefield) in the Canadian rockies & if you saw what is happening there you would have no doubts about global warming. I want someone to explain to me how burning nearly 90 million barrels of oil a day does not affect our atmosphere, & that is not counting the burning of coal, wood,natural gas,etc. Just our growing season alone has gone from 89 days to 118 in less than 20 years.The oil industry has also lots of money to put out false information. I live in Alberta where the Tar sands are. There was not a word locally about the distruction they were causing(they litrally owned the local media) until the international media got hold of the problem. They could not control that. If the Global warning proponents are wrong not much harm,but if the anti global warming supporters are wrong, what then. I would rather be sure than sorry in this case, & as I said what I have seen with my own eyes leaves me in no doubt whatsoever. I have also seen the lies & misinformation first hand, from the oil industry. The oil industry is spending more money than the tobacco industry did telling us cigarettes were good for us. Mick B.