Cities may be 8 degrees Celsius hotter by 2100 — Study

PARIS: Under a dual onslaught of global warming and localised, urban heating, some of the world’s cities may be as much as eight degrees Celsius warmer by 2100, researchers warned.

Such a temperature spike can have dire consequences for the health of city- dwellers, robbing companies and industries of able workers, and put pressure on already strained natural resources such as water.

The projection is based on the worst- case- scenario assumption that emissions of planet-warming greenhouse gases continue to rise throughout the 21st century.

The top quarter of most populated cities, in this scenario, could see the mercury rise 7o C or more by century’s end, said a study in the journal Nature Climate Change.

For some, nearly 5o C of the total would be attributed to average global warming.

The rest would be due to the socalled Urban Heat Island ( UHI) effect, which occurs when cooling parks, dams and lakes are replaced by heat- conducting concrete and asphalt – making cities warmer than their surrounds, the researcher said.

“The top five per cent ( of cities per population) could see increases in temperatures of about 8oC and larger,” study coauthor Francisco Estrada of the Institute for Environmental Studies in the Netherlands told AFP.

Estrada and a team used different projections of average planetary warming, combined with the UHI effect and potential harms, to estimate the future costs of warming on cities. — AFP