Scientists investigating how human-induced increases in atmospheric methane also increase the amount of solar energy absorbed by that gas in our climate system have discovered that this absorption is 10 times stronger over desert regions such as the Sahara Desert and Arabian Peninsula than elsewhere on Earth, and nearly three times more powerful in the presence of clouds.
A research team from the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) came to this conclusion after evaluating observations of Jupiter and Titan (a moon of Saturn), where methane concentrations are more than a thousand times those on Earth, to quantify methane’s shortwave radiative effects here on Earth.
These findings were published online today in the journal Science Advances in a paper entitled “Large Regional Shortwave Forcing by Anthropogenic Methane Informed by Jovian Observations.” The study indicates large regional variability in the ways methane acts as a solar absorber, finding that methane absorption, or “radiative forcing,” is largely dependent on bright surface features and clouds.
“When we measure the impact of methane emissions on the planet, we wrongly assume it is easy to apply calculations of methane taken locally to predict what effect the gas is having globally,” said William Collins, the study’s lead author and director of the Climate and Ecosystems Sciences Division at Berkeley Lab. “Our work represents the importance of taking into consideration what impact methane and other greenhouse gases are having not just in general, but with regional certainty.”
Read more at DOE/Lawrence Berkeley National Laboratory
Image: This simulation, showing the monthly-mean total solar absorption by methane from 2006 to 2010, indicates large regional variability in the gas' power to absorb incoming energy from the sun. Note the activity over the Sahara Desert, Arabian Peninsula, and portions of Australia - all places where bright, exposed surfaces reflect light upwards to make methane's absorptive properties up to 10 times stronger than elsewhere on Earth. (Credit: Lawrence Berkeley National Laboratory)