Targeting soot, methane as climate change culprits may be misguided
August 15, 2013 | By
Barbara Vergetis Lundin
Reducing the amount of short-lived emissions like soot and methane alone won't limit global warming as much as originally believed, according to research from Pacific Northwest National Laboratory (PNNL).
Soot remains in the atmosphere for a couple weeks; methane remains for up to a decade. These are both considered relatively short periods, making them "short-term climate forcers." The better-known and perhaps most dangerous climate change culprit, carbon dioxide, can stay in the atmosphere for 1,000-plus years. "Cutting back only on soot and methane emissions will help the climate, but not as much as previously thought," said the study's lead author, climate researcher Steve Smith of PNNL. "If we want to stabilize the climate system, we need to focus on greenhouse gases such as carbon dioxide, nitrous oxide and methane. Concentrating on soot and methane alone is not likely to offer much of a shortcut." Unlike other studies, the research used an integrated, dynamic PNNL computer model, the Global Change Assessment Model (GCAM) to evaluate the impact of reducing soot and methane emissions on the climate, taking into account ongoing future changes in technology, society and the economy, including energy and land use, as well as incorporating the greenhouse gases and pollutants that can result from those activities. The study examined what the future could look like in an idealized world where soot and methane emissions were severely cut by 2035. All feasible and available technology was used to eliminate as much methane as possible, including replacing all wood- and biomass-burning stoves with cleaner, modern stoves that use electricity or natural gas for energy. The research found that cutting soot and methane produced an average temperature reduction of 0.16 degrees Celsius by 2050, which is substantially less than the 0.5 degree reduction found in earlier studies. For further comparison, PNNL also evaluated these results against what would happen if a comprehensive climate policy were enacted. Earlier PNNL research developed such a scenario, which includes substantially reducing all greenhouse gas emissions, instead of only limiting carbon dioxide as previous short-lived climate pollutant studies did. The study found a comprehensive climate policy would produce more climate benefits by 2050 than if soot and methane were reduced alone. Focusing on reducing all greenhouse gas emissions, including methane, the comprehensive climate policy scenario also reduced the amount of soot in the atmosphere. As a result, the climate policy scenario lowered global average temperatures by 0.27 degrees in 2050, which is more than when only short-lived climate forcers were controlled. The comprehensive climate policy scenario also provided much larger temperature reductions through 2100. "Focusing on soot and methane may be worth targeting for health reasons, as previous studies have identified substantial health benefits from reducing those emissions," Smith said. "To stabilize the global climate, however, the focus needs to be on carbon dioxide and other greenhouse gases." For more: Related Article: Sign up for our FREE newsletter for more news like this sent to your inbox! © 2013 FierceMarkets. All rights reserved. http://www.fierceenergy.com |