Alister Doyle PlanetArk 15 Jun 11;
Tighter limits on soot and smog provide a quick and easy way to fight global warming while protecting human health and raising crop output, a U.N. study said on Tuesday.
It outlined 16 measures, ranging from plugging leaky gas transport pipelines to improving wood burning stoves, to limit "black carbon" -- soot -- methane and tropospheric ozone, which is a greenhouse gas that is a big component of smog.
"A small number of emission reduction measures ... offer dramatic public health, agricultural, economic and environmental benefits," Achim Steiner, head of the U.N. Environment Programme, said in a statement of the report.
The study, urging actions beyond a normal focus on curbing carbon dioxide, the main greenhouse gas from human activities, said the recommended actions could lop 0.5 degree Celsius (0.9 Fahrenheit) off rising temperatures.
That would help the world reach a goal adopted by 200 nations in Mexico last year of limiting the rise to below 2 degrees C above pre-industrial times. World temperatures have already risen by about 0.8 degree C, and are headed upwards.
Even before accounting for wider benefits, there were often low costs or even savings.
"For many of the measures, especially the methane ... there are cost savings," Johan Kuylenstierna of the Stockholm Environment Institute told a news conference in Bonn on the sidelines of June 6-17 climate talks.
PADDY FIELDS
To reduce methane, it called for better ventilation of coal mines, better use of gas associated with oil and gas production, reduced leaks from pipelines, better recycling of waste and reforms to agriculture such as better management of rice paddy fields.
To limit black carbon, it called for adoption of diesel particle filters at European Union standards, cleaner-burning stoves and a ban on the open-field burning of farm waste.
Michel Jarraud, head of the World Meteorological Organization, said the WMO would step up monitoring of the impact of the air pollutants on the climate.
The report expanded on preliminary findings from February.
It reiterated that less air pollution could avoid 2.4 million premature human deaths a year and the annual loss of 52 million tonnes, or about 2 percent, of world production of maize, rice, soybean and wheat.
The researchers, backed by a $200,000 grant from Sweden, would work out an action plan to try to work out costs and areas where the biggest gains could be made.
They also said benefits would be felt strongly in ice-covered regions of the Arctic or the Himalayas. When soot settles on ice, it darkens the surface and allows it to soak up more heat, adding to a thaw that further stokes global warming.
The report estimated that the measures could slow warming in the Arctic by about 0.7 degree Celsius by 2040, almost two-thirds of the projected warming in the region.
The report said it focused on heat-trapping pollution. Some polluting particles have the opposite impact of reflecting sunlight into space and so contributing to cooling.
(Editing by Janet Lawrence)
Curb soot and smog to keep Earth cool, says UN
Marlowe Hood Yahoo News 14 Jun 11;
PARIS (AFP) – Sharply reducing emissions of soot and smog could play a critical role in preventing Earth from overheating, according to a UN report released on Tuesday.
Curbing these pollutants could also boost global food output and save millions of lives lost to heart and lung disease, said the report from the UN Environment Programme (UNEP) and the World Meteorological Organisation (WMO).
Even as climate talks remain deadlocked on how to share out the task of cutting CO2, parallel action on "black carbon" particles and ground-level ozone would buy precious time in the quest to limit global temperature rise to 2.0 degrees Celsius (3.6 degrees Fahrenheit), it said.
Record output in 2010 of carbon from energy use and unprecedented CO2 levels in the atmosphere suggest that efforts to maintain the 2.0 C cap, widely seen as a threshold for dangerous warming, may already be doomed, say scientists.
On current trajectories, temperatures are set to go up 1.3 C (2.3 F) -- on top of the 0.9 C (1.6 F) jump since human-induced warming kicked in -- by 2050, bringing the total compared to preindustrial levels to 2.2 C (4.0 F).
But quickly tackling black carbon and smog-related ozone could slash 0.5 C (0.9 F) off the temperature increase projected for 2030, putting the two-degree target back on track, the new findings suggest.
"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."
The report was unveiled in Bonn as delegates from more than 190 nations under the UN Framework Convention on Climate Change (UNFCCC) struggle to make headway in the deeply stymied negotiations.
Black carbon, found in soot, is a byproduct of incomplete burning of fossil fuels, wood and biomass, such as animal waste. The most common sources are car and truck emissions, primitive cook stoves, forest fires and industry.
Soot suspended in the air accelerates global warming by absorbing sunlight. When it covers snow and ice, white surfaces that normally reflect the Sun's radiative force back into space soak up heat instead, speeding up the melting of mountain glaciers, ice sheets, and the Arctic ice cap.
The tiny particles have also been linked to premature death from heart disease and lung cancer.
Ground-level, or tropospheric, ozone -- a major ingredient of urban smog -- is both a powerful greenhouse gas and a noxious air pollutant. It is formed from other gases including methane, itself a potent driver of global warming.
A threefold increase in concentrations in the northern hemisphere over the last century has made it the third most important greenhouse gas.
Unlike carbon dioxide, which lingers in the atmosphere for centuries once emitted, black carbon and ozone disappear quickly when emissions taper off.
"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.
Measures recommended for reducing black carbon include mandatory use of diesel filters on vehicles, phasing out wood-burning stoves in rich 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 ozone, the report calls for policies that curb organic waste, require 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 major sources of methane.
The report estimates that nearly 2.5 million deaths from outdoor pollution, mainly in Africa and Asia, could be avoided every year by 2030 if black carbon levels dropped significantly.
Far less ground-level ozone could also avoid important losses in global maize, rice, soybean and wheat production, it said.
