A hot topic (Image/CHINA DAILY)
Inadequate defenses
Lee and his mother receive a monthly allowance of HK$4,700 ($600) from the government. The monthly rent for their small apartment is HK$3,400, leaving them just HK$1,300 for food and other necessities.
"I had to run the air conditioner on the hottest nights just so my son could sleep," said Tao, whose husband died from lung cancer seven years ago.
She eked out HK$300 a month to give Lee air-conditioned nights.
In Hong Kong, low-income families living in subdivided apartments are particularly defenseless against global warming, according to Fielding of Hong Kong University.
"Good ventilation is a determinant of good health," he said. "Imagine living in a home that lacks a flow of fresh air. That will not only trap heat, but pollutants, viruses and bacteria, so people will be infected more readily."
The warming climate also favors the growth of certain strains of bacteria. E. coli, the most common, which causes diarrhea, reproduces most efficiently at 37 C, the human core temperature.
In 2016, a group of scientists discovered that a 1 degree rise in the monthly mean temperature in Bangladesh resulted in an 8 percent rise in the incidence of E. coli.
As temperatures are projected to rise by 0.8 C by 2035, experts estimate that 800,000 new cases of E. coli-related diarrhea will emerge.
Climate change has also led to a global increase of about 9.4 percent in the transmission of dengue fever by the Aedes aegypti mosquito relative to 1950 levels, according to a report in The Lancet, a British medical journal, last year.
Aedes aegypti is not found in Hong Kong, but the city's dominant mosquito species Aedes albopictus is also a carrier.
"Higher temperatures are expanding favorable habitats for mosquitoes," Fielding said.
Gabriel Lau Ngar-cheung, professor at the Department of Geography and Resource Management at City University of Hong Kong, said the city's poorest people are the least adaptive to the warming climate.
"A 1 degree rise affects the well-off only marginally. They can turn on the air conditioning whenever they like," he said.
"But for people living at the subsistence level, it could mean real suffering, because they can't afford resources such as air conditioning to ward off damaging heat."
An uncertain future
Tao and Lee rarely travel outside Sham Shui Po, mainly because they can't afford to.
Tao, who is originally from the Chinese mainland, does not have permanent residency in Hong Kong. She stays on a Visit Visa, which means she is not allowed to work in the city.
Lee slipped on a pair of new sneakers before heading to a community center run by the Society for Community Organization, an NGO that has provided the family with furniture, computer equipment, food and a refuge from the heat for several years.
"I cherish these sneakers. They cost more than HK$100," Lee said.
Tao bought the sneakers so Lee could spend the winter months playing basketball－his favorite activity, but one he has to avoid during summer as a result of the extreme heat.
Tao is concerned that Lee has become physically debilitated by the hot summers.
She is also beset by other anxieties, such as whether he might be sick on other exam days, which could hamper his academic progress.
That fear casts a long shadow, because academic success for Lee could help him and his mother break out of the vicious cycle of poverty.
Tao's concerns may prove to be well-founded. In the years to come, the sun is likely to blaze even hotter, which would see Lee and Tao suffer further, along with 1.35 million other Hong Kong residents struggling to survive below the poverty line.
