In air pollution fight, China may start by tackling soot

David Fullbrook urges action on black carbon, now seen as a major cause of global warming

PUBLISHED : Wednesday, 06 February, 2013, 12:00am
UPDATED : Wednesday, 06 February, 2013, 1:38am

The scale of air pollution in China is, well, breathtaking. It is not only the intensity, but the pace and scale of deterioration in air quality over the past decade. And the problem has global implications even though the immediate challenges are coughs and worse.

For thousands laid sick by the pollution, one of the causes is black carbon, or soot. Some particles are tiny enough - qualifying as PM2.5 - to enter the lungs. When not damaging lungs, black carbon is disrupting the climate. In a study published online by the Journal of Geophysical Research-Atmospheres last month, scientists concluded that black carbon is the leading cause of climate change after carbon dioxide.

Black carbon fuels global warming in two ways. One, black carbon heats up when exposed to sunlight. Two, like most dark substances, it absorbs rather than reflects light. When black carbon falls to the ground, usually after a few days, the Earth's surface is left darker, reducing the reflectivity of the planet. Consequently, more solar energy is converted into heat.

The effect is pronounced where black carbon rains down on snow and ice. There, like tiny hot stones, black carbon concentrates heat which melts glaciers and ice caps.

The long-term climate consequences - higher temperatures, more extreme weather, and rising sea levels - for China and the world are another reason for the central government to implement and enforce a long-term strategy for cleaning up black carbon.

It is not technically challenging. In China, researchers from Peking University have found that two-thirds of black carbon comes from coke production, brick making, diesel fuel and household coal. Poor production methods and widespread use of coal make China the world's No 1 source of black carbon. Much is a legacy of lax policing and soft standards.

Tightening up is going to cost money and hurt profits in the short term. It could, however, be incorporated into ongoing efforts to restructure the economy, shut down obsolete factories and industries, and push viable firms to cut pollution, develop eco-products and increase profits.

There is some prospect of a comprehensive response to air pollution, which might specifically tackle black carbon. Blanket press coverage suggests public outrage has the ear of the government.

The world should take Beijing as a lesson because climate change means more than sore throats. It is disrupting the planetary cycles and rhythms. If the lesson is not heeded and the Beijing precedent holds, then households and firms face the harsh economy of a carbon-busted planet.

David Fullbrook is a sustainability economist