Updated on 29 Mar. 2013
Global Environment and Marine Department
The annual anomaly of the global average sea surface temperature in 2012 was +0.09°C above the 1981-2010 average, making it the 9th highest since 1891. The long-term trend of the global average sea surface temperature for 1891-2012 was about 0.51°C per century.
Time-series representation of global sea surface temperature annual anomalies
The 1981 - 2010 average is used as the normal. The black, blue and red lines represent annual global sea surface temperature anomalies, their five-year running mean and the long-term linear trend, respectively.
The annual mean of the global average sea surface temperature in 2012 was +0.09°C above the 1981-2010 average, making it the 9th highest since 1891. Anomalies above +0.1°C have been seen very often since 2000.
On a multi-year time scale, the global average sea surface temperature was at a local minimum in the period around 1910 and at a local maximum in the early 1940s. It subsequently remained at the same level for a while before assuming an ongoing warming trend again in the middle of the 1970s.
On a longer time scale, the global average sea surface temperature has risen at a rate of about 0.51°C per century. According to the IPCC (Intergovernmental Panel on Climate Change) Fourth Assessment Report, most of the increase seen since the mid-20th century is very likely to have been caused by the observed increase in anthropogenic greenhouse gas concentrations.