Rapid increase in ozone-depleting chloroform emissions from China

Chloroformcontributes to the depletion of the stratospheric ozone layer. However, due to its short lifetime and predominantly natural sources, it is not included in the Montreal Protocolthat regulates the production and uses of ozone-depletingsubstances. Atmospheric chloroform mole fractionswere relatively stable or slowly decreased during 1990–2010. Here we show that global chloroform mole fractionsincreased after 2010, based on in situ chloroformmeasurements at seven stations around the world. We estimate that the global chloroformemissions grew at the rate of 3.5% yr−1 between 2010 and 2015 based on atmospheric modelsimulations. We used two regional inverse modelling approaches, combined with observations from East Asia, to show that emissions from eastern China grew by 49 (41–59) Gg between 2010 and 2015, a change that could explain the entire increase in global emissions. We suggest that if chloroformemissions continuously grow at the current rate, the recovery of the stratospheric ozone layerabove Antarctica could be delayed by several years.