Reason.com, a libertarian website, has an advance copy of a New York Times op/ed piece to be published ?tomorrow? laying out the results of a Charles Koch Foundation-funded study at Berkeley (you may recall the acronym for this Berkeley Earth Surface Temperature project is "BEST)," run by former skeptic/denier Richard Muller. More details can be found here. They released preliminary findings in March 2011.
They have basically cofirmed the "hockey stick" concept, and attributed the warming to mankind:
Our results show that the average temperature of the Earth’s land has risen by two and a half degrees Fahrenheit over the past 250 years, and one and a half degrees Fahrenheit over the most recent 50 years. Moreover, it appears likely that essentially all of this increase is due to the human emission of greenhouse gases.These findings are stronger than those of the Intergovernmental Panel on Climate Change...