An aluminium smelter in Zouping, China. Two greenhouse gases whose atmospheric levels have soared in recent years have been traced to such smelters and to semiconductor factories in Japan and South Korea. Credit: Brent Lewin/Bloomberg/Getty

ATMOSPHERIC SCIENCE

 

18 AUGUST 2021

What’s the mystery source of two potent greenhouse gases? The trail leads to Asia

Atmospheric levels of two powerful heat-trapping gases are rising quickly — and are higher than official emissions records suggest.

The powerful greenhouse gases tetrafluoromethane and hexafluoroethane have been building up in the atmosphere from unknown sources. Now, modelling suggests that China’s aluminium industry is a major culprit.

The gases are thousands of times more effective than carbon dioxide at warming the atmosphere. Official tallies of tetrafluoromethane and hexafluoroethane emissions from factories are too low to account for the levels in the air, which began to rise in 2015 after seven years of relative stability.

Seeking to pinpoint the sources of those emissions, Jooil Kim at the University of California, San Diego, and his colleagues analysed air samples collected roughly every 2 hours between November 2007 and December 2019 on South Korea’s Jeju Island. The scientists also modelled the weather patterns that transported air across the island during that period, to track the gases’ origins.

The results suggest that aluminium smelters in China account for a large proportion of these chemicals in the atmosphere. Semiconductor factories in South Korea and Japan are probably also to blame.

JGR Atmos. (2021)

• Atmospheric science