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Source: Climate Spectator
Author: Andrew Freedman
January 16, 2012

Let’s face it – the prospects for containing global climate change by slashing emissions of greenhouse gases, such as carbon dioxide, are looking rather bleak these days. International treaty talks are proceeding at a snail’s pace, and after dipping during the global recession, emissions of carbon dioxide (CO2) – the most important greenhouse gas – from the energy sector climbed to record levels this year, and studies show that the effects of climate change, such as sea level rise, are now expected to be much worse than previously thought.

Now what if I told you that we could slash the rate of global warming nearly in half during the next several decades, while saving as many as 4.7 million lives a year and boosting crop yields, by addressing non-CO2 global warming agents? And, that we wouldn’t need endless rounds of United Nations climate negotiations in order to do it? You’d probably think it sounds too good to be true, like some sort of late night global warming infomercial.

According to a group of 13 scientists from the US, Europe, Africa and Asia, these goals are actually well within reach, and could be accomplished by tackling emissions of short-lived global warming agents such as soot and methane, a precursor to low-level ozone formation and a greenhouse gas in its own right.

The baker’s dozen of scientists make their case in a study published today in the prominent journal Science. Led by NASA researcher Drew Shindell, the study builds upon a report published in November by the UN Environment Programme, which also found major benefits to reducing emissions of what are known in global warming lingo as “short-lived climate forcers.”

But the new work goes beyond any other studies by identifying practical ways to reduce short-lived global warming agents, modeling how the climate system may respond to these measures, and then estimating whether the benefits would exceed the costs of taking such steps. This comprehensive approach offers a clearer path forward for policy makers to implement these solutions.

The short-lived global warming pollutants are distinct from CO2, which has hogged the limelight of global climate policy efforts for decades, since they remain in the atmosphere for a relatively short period. Whereas CO2 emitted today can remain in the atmosphere for centuries, the atmospheric lifetimes of pollutants such as soot (technically known as black carbon), as well as methane (a powerful greenhouse gas), are far shorter. Soot, for example, only stays in the air for several hours to a couple of weeks before precipitation rinses it out or chemical processes break it down.

So, as the study demonstrates, while cutting emissions of CO2 won’t have a tangible impact on global warming for another several decades, if we were to target the short-lived pollutants, we could counter some portion of global warming in the near-term. And, since methane contributes to low level ozone pollution that damage crops and human health, and soot also aggravates respiratory and cardiovascular illness, we could make dramatic gains in other areas as well.

The study is groundbreaking in that it’s the first time that scientists have quantified both the climate benefits of specific measures to reduce short-lived warming agents and performed a cost benefit analysis on these approaches.

Shindell and his colleagues found that the 14 emissions reduction actions they zeroed in on would be relatively cheap, and can be implemented with existing technologies.

“[By] applying existing, proven technology you can have large enough effects on emissions that you can really realize very substantial benefits for both climate and air quality, health and agriculture,” Shindell said in an interview with Climate Central.

To cut methane, the study looks at strategies such as capturing gas currently escaping from coal, oil and gas facilities and controlling emissions from landfills. To control soot, policies include installing filters on diesel vehicles to capture soot emissions, and increasing the use of clean-burning cookstoves in developing countries.

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