It's been pointed out that 5 or 10 years is too short of a period to base a trend on. For that matter, 150 years is too short of a period, when talking about the earth. 150 years corresponds to how long we've been observing meteorology, and how long we've said global warming has been happening. 150 years ago also happens to correspond to the coldest period in the last 10,000 years, based upon ice cores in Greenland, peat bogs, tree rings, and other measurements. It only makes sense that the temperature has gone up in that period, but it is very difficult to say if man is causing it. In fact, temperatures about 4-5000 years ago were about 2.5 deg. C higher than our current temperatures, and temperatures about 1000 years ago (the Medieval Warm Period) were about 1 deg. C higher than now. Unlikely that industrialization was causing either of those warm periods.
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