Climate change: IPCC cites global temperature rise over last century | Environment | The Observer
...This point was backed by Professor Myles Allen at Oxford University. "We have examined the forecasts made by climate scientists over the past three decades and they have been absolutely spot on in terms of predicting subsequent levels of global warming," he said. "Our climate models are robust and working well."
[Professor Jonathan Bamber of Bristol University] "One recent study found a way to assess sea ice cover in the Arctic over the past 1,600 years. At no point in that time were levels found to be as low as they are today. The current drop is probably the handiwork of human beings."