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Curbing Soot, Smog Could Help Limit Global Temperature Rise

June 14, 2011

A United Nations report released Tuesday calls for fast action on reducing emissions of black carbon, ground level ozone and methane to help limit near term global temperature rise preventing the Earth from overheating, reports AFP.

Fast action could also reduce losses of mountain glaciers and reduce projected warming in the Arctic over the coming decades by as much as two thirds.

Cutting out these pollutants now could also boost global food output and save millions of human lives lost to heart and lung disease, according to the report from the UN Environment Program (UNEP) and the World Meteorological Organization (WMO).

Close to 2.5 million premature deaths from outdoor air pollution could on average also be avoided annually by 2030, with many of those lives saved being in Asia, according to estimates.

Even as nations continue to be in a stalemate over climate change responsibilities, parallel action now on black carbon particles and ground-level ozone would buy precious time in limiting projected global temperature increases of 3.6 degrees Fahrenheit in the coming decades, the report said.

Record output in 2010 of CO2 emissions and levels in the atmosphere suggest that efforts to maintain the temperature cap may already be too late, according to climate scientists.

On the world’s current trajectories, temperatures are set to rise 2.3 degrees Fahrenheit by 2050. Add in an already 1.6 F jump since human-induced warming came into play and that would bring the total rise to 4.0 degrees in worldwide average temperature increase.

Cutting out these “short-lived” climate forcers would have an immediate benefits in respect to climate, health and agriculture, the report says. This is because, unlike CO2, which remains in the atmosphere for centuries, black carbon only exists for a few days or weeks. But even as curbing black carbon and ground-level ozone could play a key role in limiting near-term climate changes, cutting back CO2 levels is crucial for the long-term temperature outlook.

“There are clear and concrete measures that can be undertaken to help protect the global climate in the short and medium term,” said Drew Shindell, a researcher at NASA’s Goddard Institute for Space Studies and one of the 50 scientists behind the new assessment.

“The win-win here for limiting climate change and improving air quality is self-evident and the ways to achieve it have become far clearer,” said Shindell.

The report was released in Bonn as the 190-nation UN Framework Convention on Climate Change (UNFCCC) struggles to move forward in the deadlocked climate negotiations.

Black carbon, found in soot, is a byproduct of incomplete burning of fossil fuels, wood and biomass. The most common offenders are auto emissions, primitive wood stoves, forest fires and industry.

Soot suspended in the air accelerates global warming by absorbing sunlight. When it covers snow and ice, the Sun’s radiative force is unable to be reflected back into space and is instead soaked up on Earth, speeding up the melting of mountain glaciers, ice sheets, and the Arctic ice cap.

Soot has also been linked to premature death from heart disease and lung cancer.

Ground-level ozone, a huge ingredient in urban smog, is a powerful greenhouse gas and also a noxious air pollutant. It is formed from methane and other gases. Methane itself is a powerful driver of global warming.

“The science of short-lived climate forcers has evolved to a level of maturity that now requires … a robust policy response by nations,” said Achim Steiner, Executive Director of UNEP.

Recommended procedures for cutting black carbon include the use of mandatory diesel filters on vehicles, phasing out wood-burning stoves in wealthy countries, use of clean-burning biomass stoves for cooking and heating in developing nations, and a ban on the open burning of agricultural waste.

For cutting ground-level ozone, the report calls for the curbing of organic waste, requirements of water treatment facilities to recover gas, reduce methane emissions from coal and oil industries, and promote anaerobic digestion of manure from cattle and pigs, both of which are huge methane sources.

Curbing ground-level ozone could also avoid losses in global maize, rice, soybean, and wheat production, the report concludes.
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