[quote poorgradstudent]I’ve read some very rational arguments that human contribution to the global warmiing we’ve seen is a drop in the bucket compared to larger global effects beyond our control. But at least those arguments admit the earth has gotten warmer in the past five decades! [/quote]
Again, topic for another thread, but AGW is not proven.

The IPCC was even put in an embarrassing position in 2008. It had snowed in London. London has not had snow for more than 70 years.
http://www.thisislondon.co.uk/standard/article-23579420-arctic-blast-brings-london-earliest-snow-for-70-years.do

The Snow Line is Moving South

This is also why the subject has changed from ‘global warming’ to ‘global climate change’. Talk to any meteorologist, and they will tell you – the climate always changes.
BTW: It also recently snowed in Florida and Texas. When was the last time that occurred?

As for warmer over past 5 decades(500 years), that is blatantly false. Chinese records show the northern passage open/free of ice around 1470. England also used to grow grapes/make wine. Now it is only done on the individual scale.
http://www.english-wine.com/history.html
Growing grapes requires higher temperatures. That is why they are grown in the NAPA valley and not along the coast in California.