There are, if you look, some quite effective rebuttals of the key science i the IPCC findings, in particular the models which have been heavily fudge-factored to make them produce the 'correct' results. One of the models which produces the now famous 'hockey stick' sharp upturn in global temperatures has been shown to produce the same shape graph when fed with random data !

And doesn't the Greenland ice cover what was once green farmland ?

I for one, whilst accepting that it MAY be a serious issue, and very sceptical of the finding from some very compromised scientists. Just like the Cold War, Global Warming is a nice well filled trough to feed from for ages IF you are prepared to make the right noises in the right place - I think there are enough tales of mysteriously withdrawn grants etc when someone speks out against the politically 'correct' science to warrant suspicion.