Half of the cause of Greenland warming is natural

(About half of the surface warming narrows the Greenland ice sheets due to temperatures in the Pacific tropical ocean, not greenhouse gases, a new study says. here report.

>>>Seeing millions of years old radio stations under the Greenland ice sheet

Sea surface temperature in the Pacific Ocean is known to affect global climate models at lower latitudes. For example, the El Nino cycle moves rainfall throughout the world, distributing rain to the western part of North America and causing drought in Australia and Central America.

The new findings may explain why Greenland and the far north of Canada are becoming hotter and hotter than other areas of the world. Increasing temperature fluctuations have disturbed scientists: The most modern climate models, such as those in the fifth assessment report of the Intergovernmental Panel on climate change, failed to replicate the rapid warming observed in the Arctic.

'We know that global warming is caused by human effects, and can't explain why the earth is so warm up so quickly,' said the lead researcher, Qinghua Ding, a scientist. learn about climate at the University of Washington.

Researchers have come up with a number of ways to explain the rapidly rising temperature, such as the warmer Arctic Sea due to melting ice.

But instead, Ding and co-authored him to see, a relationship between tropical sea surface temperatures and North Atlantic Oscillation (NAO - North Atlantic Oscillation) , a type of climate dominates the Arctic climate. Since the 1990s, warm temperatures of the sea surface in the Western Pacific region and cool waters in the Eastern Pacific have pushed NAO into a model that allows high pressure above Greenland and the Arctic to Canada (High atmospheric pressure leads to warmer temperatures).

"We found between 20 and 50% of warming is artificial (human-induced) and the remaining 50% is natural, " Ding said. This study was published in Nature on May 7, 2014.

The relationship between the Atlantic and the Pacific

NAO is an important type of climate, which affects the size of the Arctic sea ice, the path of strong currents, and storms across North America, Atlantic and Europe.Finding a link between NAO and tropical regions could change the forecast for NAO , which has challenged accurate predictions.

'The general feeling is that the NAO is very chaotic , not linked to the conditions of the tropical sea' , Shang-Ping Xie, a climate scientist at the Research Institute Scripps Institute of Oceanography, who is not involved in the study. This rescue said. 'A clear meaning is that this connection can be exploited to improve climate forecasts in the North Atlantic region outside the tropics, where current prediction skills are low.'

Linking the Pacific and Greenland seas from atmostpheric pulse called Rossby waves . These are the winding in the high latitude wind that runs around the earth, like a strong current. The distribution of warm and cold air rising in the Pacific Ocean creates a Rossby wave, which ultimately facilitates warmth in the Greenland region.

'This is like smashing the atmosphere with a hammer at a specific area, producing a wave of high-pressure waves on the Greenland region , ' Ding said.

New connections to discover

Tropical sea temperatures have only been measured and monitored since 1979, with the advent of satellites, so researchers do not know whether the temperature cycle of the Pacific is short-lived. It has been stable for decades.

'Moreover our data is really short, so we're not sure what the real cause is , ' Ding told Live Science.

However, Ding said, the warming of the Pacific is not the same type as the El Nino cycle. Researchers are planning to find out why ocean temperatures may be related to other known climate cycles, such as Pacific Decadal Oscillation, or if this is a new variable. detected.

'This study shows how complex regional climate change is ,' said Juergen Bader, a climate scientist at the Max Planck Institute for Meteorology in Germany, who is not involved in the study. "Even remote processes have an important impact on regional climate," he said.

If the Pacific temperature pattern changes, warming in the Arctic may be slow in the coming decades, Ding said. There is some evidence alluded to in this case, such as the strong currents that attacked the East Coast with super-cold winds this year. However, human-induced global warming is capable of overcoming any natural cooling in the coming decades, the researchers said.