Deep oceans of the world sometimes can absorb enough heat to flatten the pace of global warming in periods as long as a decade, even longer-term warming, according to a new analysis conducted by the National Center for Atmospheric Research (NCAR).
The study, based on computer simulations of global climate, points deep ocean layers 1,000 feet (300 meters) as the principal heat "lost" in that period as the past decade, when global air temperature showed a tendency little. The results also suggest that several intervals, as can be expected in the next century and the global warming trend continues.
"We will see global warming goes through periods of hiatus in the future," said Gerald Meehl NCAR and lead author of the study. "However, these periods would probably last only a decade, and heating will resume . This study illustrates one of the reasons why the global temperature rise is not only a straight line. "
The study by scientists at NCAR and the Bureau of Meteorology in Australia, was published online in Nature on climate change. Funding for research through the National Science Foundation, NCAR's sponsor, and the Department of Energy.
When heat is lost
The decade of 2000 were the warmest decade of the Earth more than a century of weather records. However, the mark of a year for the warmer world, which was created in 1998, remained the same until 2010.
However, emissions of greenhouse gases continue to rise in 2000, and satellite measurements have shown that the discrepancy between the sunlight and the outgoing radiation from Earth, in fact increased. This meant that the heat was building somewhere on Earth, the 2010 study published in the NCAR scientists, researchers, Kevin Trenberth, John Fake.
The two scientists, who are co-authors of the new study suggests that the oceans could be storing some of the heat that would otherwise go to other processes, such as global warming or the floor or the melting of ice and snow more . Observations from a worldwide network of buoys showed a warming in the ocean surface, but not enough to account for heat build global economy. Although scientists suspect that the deep ocean have a role to play, little has been available to confirm this hypothesis.
To track where the heat is gone, Meehl and his colleagues used a powerful software tool called Community Climate System Model, which was developed by scientists from NCAR and the Department of Energy with colleagues from other organizations. Using the model's ability to depict the complex interactions between atmosphere, land, oceans and sea ice, they made five simulations of global temperatures.
The simulations are based on projections of future emissions of greenhouse gases from human activities, said that the temperature rises a few degrees during this century. But each simulation also showed periods where temperatures will stabilize for about a decade before climbing again. For example, a simulation of global mean temperature increases by about 2.5 degrees Fahrenheit (1.4 degrees Celsius) between 2000 and 2100, but the two rest periods of a decade during this century.
During this hiatus, the simulations showed that the extra energy came to the deeper layers of the oceans absorb a disproportionate amount of heat due to changes in ocean circulation. A wide range under the sea at about 1000 feet (300 meters), heated from 18% to 19% more during periods of rest than at other times. Instead, lower the global ocean has warmed by more than 1000 meters in less than 60% of non-silence periods of the simulation.
"This study suggests a lack of energy was really thrown into the sea," says Trenberth. "The heat has not gone away, so it can not be ignored. There must be consequences."
A model such as La Niña
The simulations also indicate that the world's oceans during periods of rest is a regional firm. During a break, the average sea surface temperatures in the tropical Pacific decreases, while tending to increase at higher latitudes, especially around 30 ° S and 30 ° N and 35 N Pacific and 40 ° N in the Atlantic, where surface waters converge to push the heat in the deep ocean.
These models are similar to those observed in the case of La Niña, according to Meehl. He added that El Niño and La Niña can be stacked on top of a broken model. Global temperatures tend to decrease slightly during the Niña, as the waters reach the surface cooling of the tropical Pacific and are expected to slightly increase during El Niño, when these waters are warmer.
"Global major disruption observed corresponded with La Niña, which is consistent with simulations," says Trenberth.
The simulations were part of NCAR's contribution to the phase of the Coupled Model Intercomparison Project 5 (CMIP5). They were executed on NCAR supercomputers the National Science Foundation sponsored by the Climate Simulation Laboratory, and on supercomputers at Oak Ridge Leadership Computing Facility and Energy National Centre for Scientific Computing Research, supported by the Office Science US Department of Energy.
Deep Ocean To Global Warming For The Cover Of The Decade Long
