350 ppm was the level of carbon dioxide in the atmosphere in 1989. Before the Industrial Revolution, it was something like 260 ppm; so apparently some "man-made" carbon dioxide is okay. The level sits at about 390 today.
Since the atmosphere passed the 350 level, ice sheets have been melting and other dramatic changes have been happening. Prominent scientists — notably NASA's James Hansen, one of the earliest to warn about global warming, and Rajendra Pachauri, head of the Intergovernmental Panel on Climate Change — have said 350 is the only safe level of carbon dioxide in the air."Ice sheets have been melting?" Whoever wrote this piece doesn't know a damn thing about what's going on except the stuff coming from warmistas, because the Antarctic ice sheet is thickening.
Item: The ice at the North Pole melted off in the 1950s, back when carbon dioxide was 315 ppm, which means perhaps 350 ppm is in fact too high?
Item: There has been no warming since 1998 despite the continued rise in atmospheric carbon dioxide.
Item: The oceans are cooler, and there's no way the atmosphere could be warming if the oceans are cooling.
Item: The sun is in a period of extended low activity, in every respect we measure.
Item: Plenty of glaciers are growing rather than retreating.
...and while we're at it, "350 is the only safe level of carbon dioxide in the air"? 350 is the only safe level? 349 is no good, 351 is no good, it must be 350 or we are all doomed? I know what they mean--that anything higher than 350 is "unsafe"--but that's not what they said, and words mean things.
It's all BS, though. CRU made up their figures (and based much of their "science" on one datum); if the "more CO2=more warming" model were even remotely correct we would have seen ever-increasing warming on a continuous curve which followed CO2 concentrations--and we haven't. In fact the case can be made that global temperature has declined slightly (particularly since January of 2007) even while CO2 continued to increase.
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Speaking of scientific illiteracy, here is a discussion of an article by a rich coastal liberal who doesn't know the difference between a periscope and a telescope, and who thinks that NASA's budget could be better used to "solve problems here on Earth".