Global South cities lack cooling capacity, new study finds

Cities in the Global South have approximately 70% less cooling capacity compared to their Northern counterparts during warm seasons, a new study found. 

The study, conducted by a team of international experts from the University of Exeter, has revealed significant disparities in the cooling benefits provided by urban green spaces between cities in the Global North and the Global South. 

Using remote sensing data, the researchers analyzed the cooling benefits of these spaces on daytime temperatures in the world’s 500 largest cities, calculating the role of urban greenery in mitigating heat stress. 

The data was used to assess three key factors: cooling efficiency, cooling capacity, and overall cooling benefit. 

Cooling efficiency measures how effectively green spaces reduce temperatures, while cooling capacity refers to the total cooling impact of existing green infrastructure.

The study found a correlation between the amount of urban green infrastructure and lower temperatures, the researchers said.

“Urban green infrastructure and temperature are generally negatively and relatively linearly correlated at landscape scales, i.e., higher quantities of urban green infrastructure yield lower temperatures,” said the study. 

The study thus underscores the urgent need for increased investment in urban green infrastructure in the Global South to tackle the growing threat of extreme heat stress. 

Rising temperatures due to climate change and the urban heat island effect will combine to create dangerous conditions for millions of people, the researchers said. 

The study also warned that temperatures could exceed 50°C in many parts of the world if global warming reaches 2°C and this combined with the urban heat island effect, which can increase temperatures by up to 10°C, does pose a significant health risk.

According to the researchers, exposure to extreme heat could lead to serious health problems, including heat stroke and death. 

“Even before such lethal temperatures are reached, worker productivity and general health and well-being can suffer,” said the study. 

The Global South has been considered to be particularly vulnerable to heat stress due to its warmer climate and rapid urbanization.

The study predicted that the frequency and duration of extreme heat events will increase in low-latitude regions, where population densities are already high and this combination of factors could lead to a sharp rise in the number of people exposed to dangerous heat conditions.