NASA's Goddard Institute for Space Studies have just released their annual Surface Temperature Analysis report, in which they release their findings on average global temperatures for the previous year. You can read the report here, but the gist of it is that 2011 was the ninth warmest year since accurate global measurements began in 1880. That puts nine of the ten hottest years in recorded history in the 21st century, and all ten in the past 13 years. The warmest year was a tie between 2005 and 2010, with 2011 only 0.12°C cooler than that.
According to GISS director James E. Hansen, "We know the planet is absorbing more energy than it is emitting, so we are continuing to see a trend toward higher temperatures. Even with the cooling effects of a strong La Niña influence and low solar activity for the past several years, 2011 was one of the 10 warmest years on record."
The video clip to the left shows how temperatures in various locations around the planet have changed over the past 131 years, with red colours indicating that temperature increases, and blue indicating cooling. To provide the baseline, global temperatures over 30 years (from 1950 to 1980) were averaged for each measuring point. The changing colours on the map show changes relative to that average temperature. Such a long period was used for the base to ensure a real average, and to iron out any temporary highs and lows. The resulting video is quite striking.