Climate change sceptics, especially those who posit against limiting anthropogenic factors that affect climate, often cite the pause in the rise of the surface-air temperatures over the last couple of decades as evidence supporting their stand. Despite the increase in the level of heat-trapping carbon dioxide, why hasn’t the planet’s surface gotten any hotter (popularly understood as global warming) since the turn of the century, they ask. Findings of a study by two scientists, published in Science and cited in The Economist, put us nearer to the answer than before. Chen Xianyao of the Ocean University of China, Qingdao, and Ka-Kit Tung of the University of Washington, Seattle, have inferred from temperature and salinity data gathered by 3,000 ocean floats that the heat has sank to the depths. In a nutshell, the faster temperature rise near the ocean floor than the surface corresponds to this period of supposed lull. The scientists found that, between 1999 and 2012,
69 zettajoules of heat (69 x 1021 joules) have been sequestered by the oceans at depths between 300 metres and 1,500 metres.
The other significant finding is that despite the Pacific’s larger expanse, it is the Atlantic which has absorbed most of heat. This could mean a paradigm shift for the world’s understanding of climate change as the Pacific’s influence on climate, such as the El Nino episodes, has been held as the most significant so far. Given that this sequestration must reverse itself at some point of time—a significant temperature difference between the surface and the depths is unsustainable, The Economist maintains—Xianyao’s and Tung’s research must prod further understanding of what changes can be expected because of the Atlantic’s influence.