Researchers at the University College London have put forth a new argument in favor of a simple solution to combating the issue of extreme heat in cities without air conditioning. The so-called “cool roof” method they found had the best mitigation performance metrics over others surveyed (green roofs, A/C, solar panels, and street-level plant integrations), reducing heat by between 1.3 and 2 degrees Celsius when applied in the right conditions. 

Lead author Dr. Oscar Brousse of the UCL Bartlett School Environment, Energy & Resources said: “We comprehensively tested multiple methods that cities like London could use to adapt to and mitigate warming temperatures, and found that cool roofs were the best way to keep temperatures down during extremely hot summer days. Other methods had various important side benefits, but none were able to reduce outdoor urban heat to nearly the same level.”

The findings will of course have bearings on public health and urban design efforts outside of London, which is largely unprepared for more frequent occurrences of extreme heat conditions. Last year, it was reported that the number of heat-related hospitalizations rose by 20% in the United States alone.