Cut short-lived pollutants to curb climate change
A report in the journal Nature Climate Change says global governments must work together to cut short-lived climate pollutants as well as combating long-lived CO2 emissions, stating that the short-lived pollutants - such as black carbon, hydrofluorocarbons (HFCs) and methane - are having a huge, short-term impact on global temperatures and air pollution.  
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Short-lived pollutants – which include black carbon, hydrofluorocarbons (HFCs) and methane – are having a dramatic, short-term effect on global temperatures and air pollution, the report claims.

It argues that prioritising cuts to short-lived pollutants is necessary to limit climate change in the short-term to less than 2OC.

Veerabhadran Ramanthan, co-author and UNESCO professor of climate policy, said: “Unlike long-lived CO2 emissions which remain in the atmosphere for hundreds to thousands of years, short-lived pollutants remain in the atmosphere for just days to a few decades, and cutting them will reduce the rate of warming within a decade.”

Black carbon – or soot – is produced by incomplete combustion of fossil fuels and has a much stronger impact on the climate than pure CO2. Although it only has a short lifespan in the atmosphere, black carbon contributes heavily to air pollution which causes millions of deaths worldwide.

HFCs occur from air conditioning and refrigeration and could account for almost 20% of climate pollution by 2020 if left unchecked.

Political confidence

The authors of the paper say limiting short-term climate change and air pollution can help create political confidence to tackle the long-term impacts of CO2 emissions.

“The fresh scientific insights about short-lived climate pollutants are opening up a new political front in the battle to mitigate climate change,” said lead author professor David Victor of UC San Diego.

“Reductions of these short-pollutants will have a huge impact on local ravages of air pollutants, which already kills seven million people every year and degrades more than a hundred million tons of crops,” said Victor. “These are not hypothetical cuts. California has already done this and has a blueprint for the world.”

Near-term progress

Durwood Zaelke, co-author and President of the Institute for Governance & Sustainable Development, added: “Technologies exist today to reduce up to 30% of methane, 75% of black carbon and nearly 100% of potent HFCs.”

Ninety countries including the USA, Canada, Mexico, India and 55 African states are already signed up to the Montreal Protocol and have committed to phasing down HFC production and consumption.

Victor added: “Slowing climate change requires fast action on additional fronts beyond the U.N. climate process. “Near-term progress is more likely to occur when using a portfolio of decentralized strategies that work on many different fronts. Action on short-lived climate pollutants will raise the odds that this time, the world will develop the confidence to get serious on climate action.”

A seperate report by the New Climate Economy last week also called for a rapid phase-out of HFCs to mitigate climate change, with these gases thought to be growing at a rate of more than 10% per year. Other reports have claimed that cutting black carbon emissions alone will not have the required impact to limit climate change to two degrees, with the National Academy of Sciences advising Governments to focus on broader carbon dioxide mitigation policies.

Matt Field