The rate of global warming has surged since 2015 and is now nearly double what it was in the 1970s, according to a study1 that tackles one of the hottest debates among climate scientists. Because the past three years have shattered temperature records (see ‘Temperature boost’), researchers have been exploring whether global warming is accelerating, and if so, why. Many scientists agree that the rate at which it is increasing has picked up. This is mainly because of a reduction in air pollution following the introduction of fuel regulations for international shipping (which has resulted in fewer pollutant particles that...