Extreme weather brought about by the El Nino phenomenon could cost Hong Kong as much as US$300 billion over the 21st century, according to a joint study by local and Singapore universities.

The study also painted a bleak picture for public health, finding that Hongkongers born during the two strong El Nino events in 1982-83 and 1997-98 could have their life expectancy reduced by five to seven months.

Led by Singapore’s Nanyang Technological University in collaboration with City University (CityU), the study analysed more than six decades of mortality records and economic data from 10 high-income Pacific Rim countries and regions.

Published in the scientific journal Nature Climate Change, the study showed that El Nino – a climate pattern involving the warming of the Pacific Ocean – was a “persistent driver of health and economic loss”, not just a short-term weather anomaly.

Researchers estimated life expectancy losses of 0.5 years for the 1982-83 El Nino and 0.4 years for the 1997-98 event.

This is equal to economic losses of US$2.6 trillion for the 1982-83 group and US$4.7 trillion for the 1997-98 batch for all the countries and regions under study.