2011 ninth warmest year in recorded history, NASA says

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2011 ninth warmest year in recorded history, NASA says

2012-01-20 20:33:46 GMT+7 (ICT)

WASHINGTON, D.C. (BNO NEWS) -- The global average surface temperature in 2011 was the ninth warmest since at least 1880, according to NASA scientists on Thursday. Nine of the ten warmest years have occurred since the year 2010.

An updated analysis released by NASA's Goddard Institute for Space Studies (GISS) in New York, which monitors global surface temperatures on an ongoing basis, showed temperatures around the globe in 2011 and were compared to the average global temperature from the mid-20th century.

The comparison shows how Earth continues to experience warmer temperatures than several decades ago. The average temperature around the globe in 2011 was 0.92 degrees Fahrenheit (0.51 Celsius) warmer than the mid-20th century baseline.

GISS director James E. Hansen stated that the planet is currently absorbing more energy than it is emitting. As a result, people around the world are continuing to see a trend toward higher temperatures.

"Even with the cooling effects of a strong La Nina influence and low solar activity for the past several years, 2011 was one of the 10 warmest years on record," Hansen said.

The difference between 2011 and the warmest year in the GISS record (2010) is 0.22 degrees Fahrenheit (0.12 Celsius). Because of the large natural variability of climate, scientists do not expect temperatures to rise consistently year after year. However, they do expect a continuing temperature rise over the coming decades.

Hansen said the first 11 years of the 21st century experienced notably higher temperatures compared to the middle and late 20th century. The only year from the 20th century which is in the top 10 warmest years is 1998.

Current higher temperatures are largely sustained by increased atmospheric concentrations of greenhouse gases, especially carbon dioxide. These gases absorb infrared radiation emitted by the Earth and release that energy into the atmosphere rather than allowing it to escape into space. As their atmospheric concentration has increased, the amount of energy "trapped" by these gases has led to higher temperatures.

According to the NASA report, the carbon dioxide level in the atmosphere was about 285 parts per million in 1880, when the GISS global temperature record begins. By 1960, the average concentration had risen to about 315 parts per million. Today it exceeds 390 parts per million and continues to rise at an accelerating pace.

In November 2011, the World Meteorological Organization (WMO) warned that the amount of greenhouse gases in the atmosphere had reached a new high in 2010, exceeding worst case scenarios which had been set in 2001. Between 1990 and 2010, the WMO recorded a 29 percent increase in radiative forcing - the warming effect on our climate system - from greenhouse gases. Carbon dioxide accounted for 80 percent of this increase, according to the WMO's Greenhouse Gas Bulletin.

"The atmospheric burden of greenhouse gases due to human activities has yet again reached record levels since pre-industrial time," WMO Secretary-General Michel Jarraud said in November. "Even if we managed to halt our greenhouse gas emissions today - and this is far from the case - they would continue to linger in the atmosphere for decades to come and so continue to affect the delicate balance of our living planet and our climate."

According to the WMO, heat-trapping carbon dioxide concentrations are the single most important man-made greenhouse gas in the atmosphere and 390 parts per million is the highest level since the start of the industrial era in 1750. The high concentrations of carbon dioxide are primarily because of emissions from combustion of fossil fuels, deforestation and changes in land-use.

In Thursday's report, Hansen said he expects record-breaking global average temperatures during the next two to three years because solar activity is on the upswing and the next El Nino will increase tropical Pacific temperatures. The warmest years on record were 2005 and 2010, in a virtual tie.

"It's always dangerous to make predictions about El Nino, but it's safe to say we'll see one in the next three years," Hansen said. "It won't take a very strong El Nino to push temperatures above 2010."

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