Warming world in range of dangerous consequences
September 17th, 2008
Scripps Atmospheric and Climate Sciences Professor V. Ramanathan. Credit: Scripps Institution of Oceanography, UC San Diego
The earth will warm about 2.4° C (4.3° F) above pre-industrial levels even under extremely conservative greenhouse-gas emission scenarios and under the assumption that efforts to clean up particulate pollution continue to be successful, according to a new analysis by a pair of researchers at Scripps Institution of Oceanography at UC San Diego.
That amount of warming falls within what the world's leading climate change authority recently set as the threshold range of temperature increase that would lead to widespread loss of biodiversity, deglaciation and other adverse consequences in nature. The researchers, writing in the online edition of the Proceedings of the National Academy of Sciences, argue that coping with these circumstances will require "transformational research for guiding the path of future energy consumption."
"This paper demonstrates the major challenges society will have to face in dealing with a problem that now seems unavoidable," said the paper's lead author, Scripps Atmospheric and Climate Sciences Professor V. Ramanathan. "We hope that governments will not be forced to consider trade-offs between air pollution abatement and mitigation of greenhouse gas emissions."
In their analysis, Ramanathan and co-author Yan Feng, a Scripps postdoctoral research fellow, assumed a highly optimistic scenario that greenhouse gas concentrations would remain constant at 2005 levels for the next century. For the concentrations to remain at 2005 levels, the emissions of greenhouse gases such as carbon dioxide must decrease drastically within the next decade. Economic expansion, however, is expected to see emissions increase. The researchers then analyzed expected future warming by assuming that the cooling effect of man-made aerosol pollution will be eliminated during the 21st Century. Currently, particulate air pollution caused by fossil fuel combustion, forest fires and smoke from cooking and agricultural waste burning serves to mask global warming caused by greenhouse gases. The smog does so chiefly by creating a dimming effect at Earth's surface.
But mitigation of this type of pollution has been increasingly successful by countries around the world. Because soot and similar particles remain airborne only for a matter of weeks, it is expected that clean-up efforts produce relatively immediate results. Therefore, the authors based their projections of temperature increase assuming the absence of these pollutants in the atmosphere.
By contrast, greenhouse gases can remain in the atmosphere for decades or, in the case of carbon dioxide, more than a century.
Ramanathan and Feng estimated that the increase in greenhouse gases from pre-industrial era levels has already committed Earth to a warming range of 1.4° C to 4.3° C (2.5° F to 7.7° F). About 90 percent of that warming will most likely be experienced in the 21st Century. In 2007, the Intergovernmental Panel on Climate Change identified a temperature increase range between 1° C and 3°C (1.8° F and 5.4°F) as the threshold at which society commits the planet to biodiversity loss and deglaciation in areas such as Greenland and the Himalayas.
The pace at which the world approaches the threshold depends in part on national and international air pollution reduction policies. Despite the masking effects of atmospheric aerosols, the authors note that their removal is still an important objective because of the deleterious human health, agricultural and water supply effects of smog. The authors point out that the real problem is not the reduction of air pollution, but it is the lack of comparable reductions in emissions of CO2 and other greenhouse gases to offset the reductions in the surface cooling effect of fog. The paper also offers potential solutions.
"Given that a potentially large warming is already in our rear-view mirror, scientists and engineers must mount a massive effort and develop solutions for adapting to climate change and for mitigating it," Ramanathan said. "Drastic reduction of short-lived warming agents is one way to buy the planet time for developing cost-effective ways for reducing CO2 concentrations."
Source: University of California - San Diego
Jun 29, 2009 |
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I for one just really dont care about climate change. It happens, it happens. We all die who cares? Its not like anyone will be there to remember...
In the past warm has been good,cold has been BAD.I see no reason why it will be any different in the future.
The people posting the stories niavely report any alarmist publication as Gospel.
While most of the people reading items on this sight know that most of the news items posted on this site are a pile of....
I thought the most biodiverse climates were rather hot, like the rainforest.
Yes but then what will happen to the precious polar bears? It's funny how science is such a big proponent to evolution but yet they think it is our job to try and prevent life from being able to have a chance to evolve under harsh circumstances. If life can survive a 15 km asteroid in the blink of an eye I am sure it will be able to handle the temperature going up 2 degrees over a 100 year period.
Thats pretty much the theory as i understand it its based on historical events of extinction.
I know this is the internet but do we really have to lower ourselves to generalisations and attack anyting that doesnt sound familiar to us?
More nuance less idiotic behaviour please
Current speed of change is challenging most but the fastest reproducing species, just because their ability to change relies on genetic change at each generation. When change happens within generation, not in 10 or perhaps 100 as it did in previous times, species really can not adapt by genetic change. They may adapt if they can move to better environment. That might work for animals, but plants are having the short stick here.
I also think that we need to find a way to scrub the skies before we will hit some runaway event like permafrost melting induced methane and CO2 release.
http://www.physor...850.html
http://www.physor...692.html
I wouldn't say 4 degrees over 100 years is a faster change than the Ice age, or the multiple impact events that the Earth has faced.
Unfortunatly it does.
What really annoys me is the authors of this article casually connect catastrophic effect to the extremely limited data they report. They don't even place a caveat like "may" or "perhaps", but rather insist a certain and inevitable causality as though they were revealing a new testament of God.
I'm still waiting for an acceptable review of the idea that oceans are warming from natural volcanic activity, and this is causing more CO2 to be released.