Updated on 25 Feb. 2016
Global Environment and Marine Department
The annual mean global average sea surface temperature in 2015 was +0.30°C above the 1981-2010 average, making it the highest since 1891. The linear trend of from 1891 to 2015 shows an increase of 0.52°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 global average sea surface temperature in 2015 was +0.30°C above the 1981-2010 average, making it the highest since 1891.
On a multi-year time scale, the global average sea surface temperature showed warming trends from around 1910 and to the 1940s and from the mid-1970s to around 2000, and remained at the same level from the 1940s to the mid-1970s and from around 2000 to the early 2010s.
A long-term warming trend is observed along with such decadal to multi-decadal variability, with the linear trend from 1891 to 2015 showing an increase of 0.52°C per century. The annual mean of the global average sea surface temperature varies in a way generally similar to that of the global average land surface temperature. It should be noted that the long-term trend observed for the period from 1880 to 2015 shows an increase of 0.87°C per century for land surface temperature, which is higher than that for sea surface temperature.
The absence of significant increase in global averages of sea surface temperature and land surface temperature since 2000 attracts attention as a hiatus in the warming trend. Meanwhile, continuous increase in global ocean heat content is observed. Recent studies have suggested that increased heat uptake through the ocean subsurface to deeper regions has contributed to the hiatus. (IPCC (Intergovernmental Panel on Climate Change) Fifth Assesment Report Box 9.2).
According to the IPCC Fifth Assessment Report, it is very likely that human influence has been the dominant cause of the warming observed since the mid-20th century.