Scientists urge curbing ‘black carbon’

A ban on traditional wood burning stoves and stopping leaks from long distance gas pipelines are among measures that could help slow global temperature rises in coming years, a group of leading atmospheric scientists has found.

Such measures would curb so-called black carbon, a major component of soot, and ground level ozone, a big part of urban smog, says a new study coordinated by the United Nations Environment Programme and World Meteorological Organisation.

The report was released in Bonn, where delegates from more than 190 countries are struggling to make progress in the latest round of talks under the UN Framework Convention on Climate Change, an international treaty that came into force in 1994 to tackle global warming.

Many global warming efforts focus on cutting emissions of carbon dioxide, the main greenhouse gas.

But the authors of the new study say their work has shed new light on how black carbon and tropospheric ozone – found in the lower layer of the atmosphere – contribute to climate change.

They say their recommendations should not be seen as an alternative to cutting carbon dioxide emissions but an important addition.

“This report has brought clarity to the complexity of the heating and cooling effects of a range of pollutants and uses the science to show that there are clear and concrete measures that can be undertaken to help protect the global climate in the short to medium term,” said Drew Shindell of NASA’s Goddard Institute for Space Studies, who chaired the assessment.

“Perhaps the most intriguing link is between emissions of methane and the formation of tropospheric ozone. Methane is a powerful greenhouse gas in its own right, but it has emerged that it is also triggering a great deal more global warming by contributing to the formation of significant levels of ground level ozone – indeed more than was previously supposed.”

The study recommends a series of measures, many of which are already in use in many countries.

They include:

  • Replacing wood burning stoves in developed countries with pellet stoves and boilers using fuel from recycled wood and sawdust.
  • Making diesel particle filters for vehicles part of emissions and fuel standards.
  • Banning open burning of agricultural waste.
  • Upgrading water treatment works to include gas recovery.
  • Cutting methane emissions from coal, oil and gas industries.

If such measures were fully implemented, the projected temperature rise between now and the 2030s could roughly halve, the study says, though its authors concede more work needs to be done on how to introduce such steps globally.

Further study is also required to determine the costs of such measures.

Without action to curb climate change emissions, scientists have estimated global temperatures will rise on average by a further 1.3 degrees Celsius by mid-century.