Three steps Hong Kong must take to save city from ‘deadly hot’ days

“It’s so hot one could die” is a Chinese expression that pretty much reflects the reality of today’s Hong Kong, with its increasingly scorching and sultry weather. Unfortunately, people’s lives will continue to be threatened by the extreme weather that we have faced so often this year.

Hot weather can kill: numerous studies highlight this. In her research, Professor Emily Chan Ying-yang at Chinese University’s Faculty of Medicine and one of Hong Kong’s leading health and climate change experts, has found that rising temperatures are linked with increased health risks and mortality rate. One of her studies found that a one degree rise above 29 degrees Celsius was associated with a 4.1 per cent increase in natural mortality in areas with a high urban heat island effect, such as Mong Kok, Tsim Sha Tsui and Causeway Bay.

Another study co-authored by Derrick Ho Hung-chak, research fellow at the Department of Land Surveying and Geo-Informatics of Polytechnic University, along with Chinese University researchers, found that persistently hot nights increase the mortality risk. One finding was that if there are at least five sizzling hot days or nights in a seven-day period, the mortality rate can increase by over 15 per cent in the short term.

Let’s put these studies into perspective: assuming carbon emissions continue to rise throughout the 21st century and taking into account the effects of urbanisation, the Hong Kong Observatory predicts Hong Kong will heat up by 3 to 6 degrees Celsius in the late 21st century, compared to the 1986-2005 average of 23.3 degrees. Moreover, there will be an average of more than 100 very hot nights (over 28 degrees Celsius) and scorching days (more than 33 degrees) every year.