Rapid rise in methane emissions in 10 years surprises scientists

Methane warms planet 20 times as much as similar CO2 volumes but lack of monitoring means scientists can't be sure of sources

Emissions of the powerful greenhouse gas methane have surged in the past decade, threatening to thwart global attempts to combat climate change.

Scientists have been surprised by the surge, which began just over 10 years ago in 2007 and then was boosted even further in 2014 and 2015. Concentrations of methane in the atmosphere over those two years alone rose by more than 20 parts per billion, bringing the total to 1,830ppb.