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The research, published on Tuesday in the journal Nature Climate Change, used data collected from the array of about 3500 Argo buoys from 2006-13 to show temperatures were warming at about 0.005 degrees a year down to a depth of 500 metres and 0.002 degrees between 500-2000 metres.

Oceans south of the 20-degree latitude accounted for two-thirds to 98 per cent of the heat gain during the period studied, with three giant gyres in the southern Pacific, Indian and Atlantic oceans largely responsible for drawing down the extra warmth.

“The global ocean heat content right now is the most reliable metric of that radiation imbalance” between the energy received from the sun and what is radiated back to space, said Susan Wijffels, an oceans expert at the CSIRO and one of the report’s authors………..

“The ocean is just vertically transferring the heat away from the surface to the depth,” Dr Wijffels said. “The ‘hiatus’ is not meaningful.”

Even with the relative slowdown in surface temperature increases, 14 of the world’s 15 warmest years on record have been in the 21^st century, the World Meteorological Organisation said on Monday.

The United Nations body also confirmed that 2014 was the hottest year, edging out 2010 and 2005. The readings were based in part on United States agencies, including NASA which last month also declared 2014 as its warmest year.

John Church, another of the paper’s authors and also from the CSIRO, said the temperatures in the atmosphere – which accounts for just 1 per cent of the planet’s heat uptake – would rise sharply if oceans absorbed less of the heat……..

As it is, warming oceans are swelling in volume, lifting sea levels, and also affecting ecosystems, he said.

“If we want to avoid the worst impacts of climate change then we need to start taking some mitigation action,” Dr Church said. This included cutting carbon emissions and lifting renewable energy targets at home and overseas.

Future Argo missions will extend coverage to higher latitudes, including sea-ice zones, and reach depths of 6000 metres.

However, Dr Wijffels said Australia’s contribution is in doubt with about half of its Argo budget tied up with the Abbott government’s stalled higher education reform bills.  Those funds run out “in a few months”, she said.

The Nature study was led by Dean Roemmich of the California-based Scripps Institution of Oceanography. http://www.smh.com.au/environment/climate-change/southern-oceans-play-major-role-in-absorbing-worlds-excess-heat-study-finds-20150202-133j2p.html