According to NOAA, 2011 was the 11th warmest year on record in terms of global average temperature since modern records began around 1880. The global average temperature was .92 degrees Fahrenheit above normal.
While that is fairly warm, what really stands out is the fact that 2011 was the warmest La Nina year on record. We have pretty accurate records of El Nino / La Nina events at least back to around 1950.
So as you can see in the yearly temperature departure from normal graph, there has been an overall uptick in temperature with the El Nino years (in red) showing an extra spike up and the La Nina years (in blue) showing a small drop. La Nina is characterized by cooler than normal waters in the tropical Pacific Ocean between South America and Indonesia. This and its opposite cousin, El Nino, help shape steering currents and weather patterns around the world.
This post was written by Tony Schumacher on February 22, 2012