September 20, 2017

Howarth: methane must be controlled now

A study by Robert Howarth, a Cornell ecology professor, titled “Bridge to Nowhere,” warns that methane emissions must be controlled immediately if a climate-system tipping point is to be avoided. Among his observations:

“Natural gas – that once seemingly promising link between the era of oil and coal to the serenity of sustainable solar, wind and water power – is a major source of atmospheric methane, due to widespread leaks as well as purposeful venting of gas.”

“If we hit a climate-system tipping point because of methane, our carbon dioxide problem is immaterial.”

A May 14 article by Blaine Friedlander at phys.org, titled “Control methane now, greenhouse gas expert warns, summarizes the conclusions of the study, which is to be published on May 20 in the journal Energy, Science and Engineering.

The article says in part:

Natural gas – that once seemingly promising link between the era of oil and coal to the serenity of sustainable solar, wind and water power – is a major source of atmospheric methane, due to widespread leaks as well as purposeful venting of gas. Howarth points to “radiative forcing,” a measure of trapped heat in Earth’s atmosphere from man-made greenhouse gases. The current role of methane looms large, he says, contributing over 40 percent of current radiative forcing from all greenhouse gases, based on the latest science from the Intergovernmental Panel on Climate Change.

The role of methane as a driver of global warming is even more critical than this 40 percent value might indicate, Howarth notes. The climate system responds much more quickly to reducing methane than to carbon dioxide. If society aggressively controlled carbon dioxide emissions, but ignored methane emissions, the planet would warm to the dangerous 1.5 to 2.0 degree Celsius threshold within 15 to 35 years. By reducing methane emissions, society buys some critical decades of lower temperatures.

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