One way of keeping an eye on climate change is to look at what the market thinks is happening. Hence these graphs from Intrade which give a probability of a year being the warmest on record.
The Intrade contracts, where people back their opinion about what is happening with their money, are based on the data published by the NASA Goddard Institute for Space Studies on “surface air measurements at meteorological stations and ship and satellite measurements of sea surface temperature”.
Further details can be found HERE
Average Global Temperature for 2011 to be the warmest on record