Today Slashdot featured a story about global warming, the lead-in to which appeared in my Jabber client as follows:
Research from the University of East Anglia in Norwich, U.K. shows that the 20th century was the warmest for the northern hemisphere since approximately 800AD. Historical climate data were calculated from weather 'proxies' such as tree rings, ice cores, and seashells from Europe, Asia, and North America, and attempted to address the shortcomings of earlier studies. The findings support the argument for global warming as a result of human interference rather than natural climate change.
Let's say you were a sophisticated climate scientist back in 800 AD. And let's assume the eighth century was the warmest on record since approximately 400 BC. Would you be justified in asserting that the medieval global warming was a result of human interference?
And how about the global cooling of the late medieval period? Was that, too, a result of human interference? Or is global cooling somehow natural but global warming is the result of human interference?
People, the earth has been heating and cooling since the very beginning, and humans haven't had anything to do with it before, so I see little reason to think we have anything to do with it now. Can anyone prove that the twentieth century is any different from the eighth century in this regard?
Peter Saint-Andre > Journal