An analysis, carried out by a scientist of Indian origin, along with his colleagues, has shown that irreversible global warming will lead to biodiversity loss and substantial glacial melt.
The scientist in question is Professor V. Ramanathan from Scripps Institution of Oceanography at UC (University of California) San Diego.
The analysis has estimated that the earth will warm about 2.4 degree C 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.
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 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," he added.
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.
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 degree C to 4.3 degree C.
About 90 percent of that warming will most likely be experienced in the 21st Century.
"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," said Ramanathan.
"Drastic reduction of short-lived warming agents is one way to buy the planet time for developing cost-effective ways for reducing CO2 concentrations," he added.