Earth to get hotter despite global warming slowdownby Dharmendra Kapri | 25-07-2015 10:51 |
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NASA research results published in Nature Climate Change that hinges on a new and more detailed calculation of the sensitivity of earth's climate to the factors that cause it to change, such as greenhouse gas emissions, has warned that the earth's climate would continue to warm during this century on track with previous estimates, despite the recent slowdown in the rate of global warming.
Drew Shindell, a climatologist at NASA's Goddard Institute for Space Studies in New York found that the earth is likely to experience roughly 20 per cent more warming than estimates that were largely based on surface temperature observations during the past 150 years.
Research shows that the global temperatures have increased at a rate of 0.12 degrees Celsius per decade since 1951. Since 1998, the rate of warming is however shown to be only 0.05 degrees Celsius per decade - even as atmospheric carbon dioxide continues to rise at a rate similar to previous decades. The research suggested Earth may be less sensitive to greenhouse gas increases than previously thought.
To put a number to climate change, researchers calculate what is called earth's transient climate response and this calculation determines how much global temperatures would change as atmospheric carbon dioxide continues to increase at about one per cent per year until the total amount of atmospheric carbon dioxide has doubled. The estimates for transient climate response range around 1.4 degrees Celsius as against IPCC's estimate of 1.0 degrees Celsius. The study estimates a transient climate response of 1.7 degrees Celsius, and determined it is unlikely values will be below 1.3 degrees Celsius.
According to the researchers it is necessary to account for the effects of atmospheric aerosols in order to understand the role played by carbon dioxide emissions in global warming. While multiple studies have shown the northern hemisphere plays a stronger role than the southern hemisphere in transient climate change, this has not been included in calculations of the effect of atmospheric aerosols on climate sensitivity.
When corrected, the range of likely warming based on surface temperature observations is in line with earlier estimates, despite the recent slowdown, researchers report. The Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), issued in 2013, also reduced the lower range of Earth's potential for global warming. |