THE THICK smog that frequently hangs over Beijing and other Asian mega-cities could be lifted by targeting “black carbon”, methane and ground-level ozone – with huge benefits to people’s health and the global climate, a major new study has shown.
Commissioned by the UN Environment Programme (Unep) and the World Meteorological Organisation, the study found that rapid action to deal with these air pollutants could “significantly increase the chances of keeping temperature rise below 2 degrees Celsius”.
“Black carbon” is the principal component of soot and is formed from the incomplete combustion of fossil fuels, wood and biomass. The main sources are emissions from cars and trucks as well as from primitive cooking stoves, forest fires and some industrial facilities.
Big cuts in emissions of black carbon would improve people’s health and avoid close to 2.5 million premature deaths a year from air pollution worldwide by 2030, with many of those lives saved being in Asia, the Stockholm Environment Institute estimated.
Highlighting the “co-benefits” of taking action on air pollution, the institute estimated that major cuts in ground-level ozone would also reduce damage to crops by between one to four per cent of the annual global production of maize, rice, soybean and wheat.
Cutting black carbon levels in high mountain regions such as the Himalayas could slow the melting rates of glaciers and reduce the risk of associated catastrophic outburst floods, it said.
Johan Kuylenstierna, who led the study involving 50 researchers and over 100 peer-reviewers, said the measures being proposed – such as fitting particle filters to diesel-powered vehicles – already exist, and most of them would achieve cost savings over time.
He stressed reducing black carbon was complementary and not an alternative to reducing concentrations of carbon dioxide in the atmosphere. “If we don’t take the measures, the 2 degree threshold will be exceeded around mid-century”, he warned.
Although there was not enough time to address the cost issue, Dr Kuylenstierna said the institute hoped to have that done in time for December’s climate summit in Durban. But recovering methane from landfills and sewage treatment plants was profitable.
Unep’s chief scientist Joseph Alcamo said it had been working for 10 years on black carbon, methane and ground-level ozone, but it was only now it had been validated scientifically. “We have not found the silver bullet, but what we have found is a strategy.”
Suraya Sethi, an adviser to the government of India, said it was “in the interests of developing countries to addressing these issues, to reduce air pollution. In Delhi, this had been done by replacing diesel buses with vehicles powered by compressed natural gas.
“We don’t necessarily want to tag it along with the climate talks, but the impacts [of dealing with black carbon] are so near-term and so immediate, I think there will be regional action, national action, and you could feel them in five years time”, he said.
Emi Hijino, head of Sweden’s delegation at the Bonn talks, announced that her government would support further work by the Stockholm institute aimed at assisting other countries on the next steps towards taking fast action on black carbon, methane and ozone.
