A ‘robust’ case for prompt action on short-lived climate forcers

Written by Marion Davis

Thursday, 08 December 2011 01:00

SEI-coordinated UNEP report identifies 16 strategies to reduce black carbon, tropospheric ozone and methane, with region-by-region priorities, cost and benefit analyses.

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Six months ago, the United Nations Environment Programme and the World Meteorological Organization released a report showing that addressing short-lived climate forcers could reduce global warming between now and 2050 by 0.5°C and help avoid 2.4 million premature deaths and the loss of 55 million tones of crop yield each year after 2030.

The report identified 16 specific measures that used existing technologies and could yield multiple benefits. Now, as a follow-up, UNEP has published a region-by-region analysis of the costs and benefits of each measure, to help policymakers prioritise their efforts.

For example, the report shows, the greatest reductions in methane emissions in North East Asia, South East Asia and the Pacific can be achieved by capturing gases now released by coal mines, while in Africa, the single biggest methane source to tackle is fugitive emissions from oil and gas production.

Similarly, replacing traditional biomass cookstoves would make the biggest impact on black carbon emissions in Africa, Asia and the Pacific, whereas in North America and Europe, the biggest black-carbon source to tackle is traditional wood stoves.

A strong case for action
Together, the 16 measures could reduce global methane emissions by about 38 per cent and black carbon emissions by about 77 per cent if implemented by 2030, the report shows.

“The science to support action on short-lived climate forcers is quite robust,” said Johan C.I. Kuylenstierna, director of the SEI York Centre, who coordinated an international team of 34 authors for the project.

“In fact”, he added, “these measures represent ‘no-regrets’ policies, because they yield multiple benefits beyond slowing climate change. However, it’s important to stress that to achieve such benefits, all these measures would have to be implemented on a large scale by 2020.”

The report was funded by the Swedish government and released Nov. 25. Its findings were also presented Dec. 8 at a side-event during the UN Climate Change Conference in Durban.

No substitute for CO₂ reductions
“These measures are not exotic; they do not depend on new technologies, but are measures that in some parts of the world are already being followed,” UNEP Chief Scientist Joseph Alcamo said at the side-event.

“It’s not a silver bullet, but it certainly can also be a powerful strategy to complement needed CO₂ reductions,” Alcamo said. These are short-term solutions, however, he noted, and they’ll be “relatively ineffective” at slowing long-term climate change. Thus, he stressed: “Under no circumstances can they be viewed as a substitute for CO₂ reductions. They can complement CO₂ reductions.”

Cooking over a smoky fire in Pakistan. FLICKR/Chris De Rham (ah-zut)

Long-term cost savings
About half the black carbon and methane reductions, the report shows, can be achieved through measures that pay for themselves over their lifetimes, even without accounting for their health and ecosystems benefits. For example, recovering rather than emitting natural gas during oil production, allow methane to be harvested as a clean fuel. Likewise, replacing inefficient cookstoves and traditional brick kilns would reduce fuel costs.

But “prevailing short-term profit expectations” make these measures less appealing to private investors, the report notes, so “it is unlikely that the measures would be implemented solely through market forces.” Thus the report urges governments to provide the needed push with start-up funding, price guaranties, and other mechanisms.

The report outlines options and enabling mechanisms at the national, regional and global levels that countries can use to formulate effective plans for their particular needs. It also shows where the benefits of each measure would accrue, indicating which measures might be best-suited for national, regional or global-level interventions.

Most black carbon measures, for example, would yield almost all their benefits in the countries where they’re implemented – though particles also travel and are contributing to local warming in the Arctic and the Himalayas, and accelerating ice and snow melt.

With methane, the benefits of harvesting gas for fuel, for example, would be local, but the benefit of not having methane contribute to the formation of ground-level ozone, which reduces crop yields, would extend across continents.

Learn more and download the report (external link to UNEP)

Download a brief summary for policymakers (PDF, external link to UNEP)

Read the UNEP press release (PDF, external link to UNEP)

Read about a conference on SLCFs held in Bangladesh in October as part of this project »