Global warming has heated the oceans by the equivalent of one atomic bomb explosion per second over the last 150 years, according to new research findings.
More than 90% of humanity's greenhouse gas emissions were absorbed by the seas, with only a few percent heating air, land and ice caps. The enormous amount of energy added to the oceans leads to sea-level rise and intensification of hurricanes and typhoons.
Much of the heat was stored in the depths of the ocean, but here the measurements began only in recent decades and existing estimates Of the total heat that the oceans have taken up, the time lasts until about 1950. The new work is enough back to the year 1871. Scientists have said that understanding past changes in marine heat has been crucial in predicting the future impact of climate change.
A Guardian The calculation showed that the average warming over this period of 150 years corresponded to about 1.5 atomic bombs in Hiroshima size per second. However, warming has accelerated with the increase in carbon emissions during this period, and has now equaled three to six atomic bombs per second.
"I try not to do this kind of calculation just because I find it disturbing. Said Professor Laure Zanna of Oxford University, who led the new research. "We usually try to compare the heating with the energy consumption of [human] to make it less scary."
She added, "But obviously we put too much energy into the climate system, and many end up in the ocean,. There is no doubt. "The total heat that the oceans have absorbed over the last 150 years was about 1000 times the annual energy consumption of the entire world population.
The study was published in the journal Proceedings of the National Academy of Science and combined measurements of the surface temperature of the ocean since 1871 using computer models of ocean circulation.
Prof. Samar Khatiwala, also at Oxford University and part of the team, said, "Our approach is like painting. different parts of the sea surface with dyes of different color and monitoring, as they spread in the interior over time. If we know what the sea surface temperature anomaly was in the North Atlantic in 1871, we can find out how much it will contribute to warming in the deep Indian Ocean in 2018.
Rising sea levels were one of the most dangerous long-term effects of climate change, endangering the lives of billions of people living in coastal cities and assessing future rises are crucial to defense preparedness. Part of the increase is due to the melting of land-bound ice in Greenland and elsewhere, but another important factor was the physical expansion of the water as it warmed.
However, the oceans do not warm up evenly as the ocean currents transport heat around the world. The reconstruction of the amount of heat absorbed by the oceans in the last 150 years is important as it represents a basis. In the Atlantic, for example, the team found that half of the increase recorded since 1971 in low and mid-latitudes was due to heat transported by currents into the region.
The new work would help researchers to make better predictions for sea-level rise in different regions in the future. "Future changes in maritime transport could have serious consequences for the rise in regional sea level and the risk of coastal flooding," the researchers said. "Understanding the change in ocean heat and the role of circulation in shaping warming patterns remains the key to predicting global and regional climate change and sea-level rise."
Dana Nuccitelli, an environmental scientist not involved in the new research, said: "The ocean warming rate has increased as global warming has accelerated. The value in recent decades has been between about three to six Hiroshima bombs per second, depending on which record and what time frame is used. This new study estimates the ocean warming rate at about three Hiroshima bombs per second for the period from 1990 to 2015, which is at the lower end of other estimates. "