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Some Historical Perspective
...I’m looking at the temperature record as read from this central Greenland ice core. It gives us about as close as we can come to a direct, experimental measurement of temperature at that one spot for the past 50,000 years. As far as I know, the data are not adjusted according to any fancy computer climate model or anything else like that....

...Yes, Virginia, there was a Medieval Warm Period, in central Greenland at any rate. But we knew that — that’s when the Vikings were naming it Greenland, after all. And the following Little Ice Age is what killed them off, and caused widespread crop failures (and the consequent burning of witches) across Europe. But was the MWP itself unusual?...

...Well, no — over the period of recorded history, the average temperature was about equal to the height of the MWP. Rises not only as high, but as rapid, as the current hockey stick blade have been the rule, not the exception...

...In other words, we’re pretty lucky to be here during this rare, warm period in climate history. But the broader lesson is, climate doesn’t stand still. It doesn’t even stand stay on the relatively constrained range of the last 10,000 years for more than about 10,000 years at a time.

Does this mean that CO2 isn’t a greenhouse gas? No.

Does it mean that it isn’t warming? No.

Does it mean that we shouldn’t develop clean, efficient technology that gets its energy elsewhere than burning fossil fuels? Of course not. We should do all those things for many reasons — but there’s plenty of time to do them the right way, by developing nanotech. (There’s plenty of money, too, but it’s all going to climate science at the moment. :-) ) And that will be a very good thing to have done if we do fall back into an ice age, believe me.

For climate science it means that the Hockey Team climatologists’ insistence that human-emitted CO2 is the only thing that could account for the recent warming trend is probably poppycock....