67 'deadly' hot days to scorch Seoul in 2100: study
A lioness dozes at the Seoul Children’s Grand Park on June 19. The weather authority issued heat alerts nationwide on the day. / Yonhap
By Ko Dong-hwan
Over 60 days of “deadly heat” will hit Seoul in 2100 unless global greenhouse gas emissions are reduced, according to American research.
Camilo Mora and others from the University of Hawaii at Manoa make the prediction in a paper that online journal Nature Climate Change published on June 19.
Under the scenario of “Representative Concentration Pathways 8.5” (a forecast the Intergovernmental Panel on Climate Change (IPCC) adopted based on global temperatures rising by 3.7 degrees Celsius by 2100), Seoul would experience deadly heat for one day in 2025, three days in 2030, five in 2040, seven in 2050, 20 in 2060, 35 in 2075 and 67 in 2100.
RCP 8.5 is the worst-case scenario among the IPCC’s three projections of global temperature trajectories that Mora studied. The other two, RCP 2.6 and RCP 4.5, forecast global temperature peaks by 2020 and 2040, respectively, which then start to reduce.
The study also made predictions for other cities under RCP 8.5 in 2100. Among the worst were Hong Kong with 174 days of deadly heat, Shanghai 123 days, Sao Paolo 110 days, Tokyo 84 days, Chicago 68 days and Rome 59 days. Cities expected to fare comparatively well were London, with no deadly heat days, San Francisco two days and Berlin four days.
The study quantified the danger of global warming-induced extreme heat by linking it to past heat-related deaths ― 783 examples from 164 cities in 36 countries.
“An increasing threat to human life from excess heat now seems almost inevitable, but it will be greatly aggravated if greenhouse gases are not considerably reduced,” Mora said.
She said her team identified a “global threshold, beyond which daily mean surface air temperature and relative humidity become deadly.”
The study said about 30 percent of the global population is now exposed to the threshold for at least 20 days a year. By 2100, the figure is estimated to hit 48 percent if greenhouse gases are greatly reduced, but continue to 74 percent if emissions keep growing.