Seawater to a depth of up to 700 meters is warming at a pace of 0.02 degree every 10 years worldwide, according to an analysis by the Meteorological Agency.
In its first analysis into deep-water temperatures, the agency says that rises in seawater temperatures could lead to higher sea levels because heat expands, and to an accelerated pace of global warming because the warmer water may absorb less carbon dioxide.
The agency used temperature data up to 700 meters below sea level sampled at between roughly 70,000 and 2 million spots each year since the 1950s. The data were collected by observation ships from the agency and other countries, and commercial ships that sampled sea temperatures at research institutes' request.
In satellite observations, sea levels worldwide have risen at a pace of 2.95 mm every year since 1993. According to the Meteorological Agency, about one-third of the rise, or about 0.88 mm, can be attributed to increases in seawater temperatures up to 700 meters deep, according to the agency.
While the average seawater temperature for the world in 1950 was 0.069 degree below the average between 1981 and 2010, the figure in 2011 was 0.075 degree above the average. With yearly differences adjusted, that translates into a rise of 0.02 degree every 10 years.