For those in the northern hemisphere, we are still shivering from our winter. Well it is getting warmer. According to NOAA (National Oceanic and Atmospheric Administration), the combined average temperature over global land and ocean surfaces for February 2013 tied with 2003 as the ninth warmest on record, at 0.57°C (1.03°F) above the 20th century average of 12.1°C (53.9°F). The global land surface temperature was 1.00°C (1.80°F) above the 20th century average of 3.2°C (37.8°F), tying with 2010 as the 11th warmest February on record. For the ocean, the February global sea surface temperature was 0.42°C (0.76°F) above the 20th century average of 15.9°C (60.6°F), making it the eighth warmest February on record. So despite some snow it is warmer than it used to be.
Global warming is the rise in the average temperature of Earth's atmosphere and oceans since the late 19th century and its projected continuation. Since the early 20th century, Earth's mean surface temperature has increased by about 0.8 °C (1.4 °F), with about two-thirds of the increase occurring since 1980.
Temperature changes vary over the globe. Since 1979, land temperatures have increased about twice as fast as ocean temperatures (0.25 °C per decade against 0.13 °C per decade). Ocean temperatures increase more slowly than land temperatures because of the larger effective heat capacity of the oceans and because the ocean loses more heat by evaporation. The northern hemisphere warms faster than the southern hemisphere because it has more land and because it has extensive areas of seasonal snow and sea-ice cover subject to ice-albedo feedback. Although more greenhouse gases are emitted in the Northern than Southern Hemisphere this does not contribute to the difference in warming because the major greenhouse gases persist long enough to mix between hemispheres.
It was much warmer than average across much of Mexico, Central America, northern South America, parts of Africa, the Middle East, and Southeast Asia. It was cooler than average across the southwestern United States, part of western Europe, Mongolia, and eastern Siberia, where some regions experienced record cold.
In the high northern latitudes, Iceland was "exceptionally warm" for February, according to the Icelandic Meteorological Office. The capital city of Reykjavic had its third warmest February in its 143-year period of record.
Finland was milder than average during February. Austria was 1.0°C (1.8°F) below the 1981—2010 average. Areas in the Alps were up to 4.1°C (7.4°F) colder than average.
Following its all-time record-warmest month in January, the February average maximum and minimum temperatures across Australia remained above the 1961—1990 average, though not as extreme as the previous month, ranking as the 16th and 35th warmest for February, respectively.
The February 2013 globally-averaged ocean temperature anomaly of 0.57°C (1.03°F) was the eighth warmest on record for February. Somewhat neutral conditions were present across the central and eastern equatorial Pacific Ocean, with sea surface temperatures below average across the eastern half of the equatorial Pacific. According to NOAA's Climate Prediction Center, neutral conditions are favored into the Northern Hemisphere summer 2013.
In other regions, it was notably warmer than average across the equatorial Atlantic, Indian, and western Pacific Oceans, with record warmth observed in the Indian Ocean near parts of northern and southwestern Australia, the seas of Borneo to New Guinea, and some areas of the Arctic Seas.
The December 2012—February 2013 average seasonal temperature across the world's land and ocean surfaces was the 12th warmest on record for the period, at 0.51°C (0.92°F) above the 20th century average. With neutral conditions persisting during all three months in the eastern and central equatorial Pacific Ocean, the globally-averaged ocean surface temperature was the eighth warmest for December—February, with record-warm temperatures observed across the Indian Ocean near northwestern and southwestern Australia and some areas of the Arctic Seas.
Globally, the land surface temperature tied with 1992 as the 15th warmest December—February on record. There were differences between the hemispheres, however, with the Southern Hemisphere land observing its second warmest summer on record (0.98°C / 1.76°F above average) and the Northern Hemisphere land observing its 27th warmest winter on record (0.61°C / 1.10°F above average). It was cooler than average across parts of Siberia, Mongolia, northeastern China, parts of northern Canada, and much of the western United States.
For further information see State of the Climate.
Warming? image via Wikipedia.