The average global surface temperatures haven't increased over the past 13 years because strongest trade winds have forced the heat from global warming into the western pacific oceans, according to a University of New South Wales study. Researchers said that when these trade winds slow down, the heat will swiftly return to the atmosphere, leading to a sudden rise in global average temperatures.
The study found that the accelerated winds in the Pacific Ocean brought the deeper colder water to the surface and forced the warmer water from the atmosphere to accumulate below surface of the Western Pacific Ocean.
"Scientists have long suspected that extra ocean heat uptake has slowed the rise of global average temperatures, but the mechanism behind the hiatus remained unclear. But the heat uptake is by no means permanent: when the trade wind strength returns to normal - as it inevitably will - our research suggests heat will quickly accumulate in the atmosphere," Professor Matthew England, lead author of the study, said in a press release.
Researchers said that the strengthening of the pacific trade winds that began during the 1990s continues till today. Since the earlier climate models did not take into the account the strengthening of the trade winds, they failed to report the hiatus in warming. When the researchers incorporated the trade winds in their current models, the global average temperatures were similar to that of observations during the hiatus.
"The winds lead to extra ocean heat uptake, which stalled warming of the atmosphere. Accounting for this wind intensification in model projections produces a hiatus in global warming that is in striking agreement with observations," Prof England said.
Researchers said that people should not get mistaken with the current hiatus since it is just another pause in warming. Since the heat is not pushed deep into the ocean, it will eventually rise to the surface and cause sudden increase in global temperatures.
"Climate scientists have long understood that global average temperatures don't rise in a continual upward trajectory, instead warming in a series of abrupt steps in between periods with more-or-less steady temperatures," said Prof England.
The finding is published in the journal Nature Climate Change.
