Cities like Rio de Janeiro and São Paulo are overpopulated, where most people live in poor conditions of inadequate housing and sanitation, such as slums, with little and no trees and high temperatures. These people have low access to sanitation, public health and residential cooling and are vulnerable to the effects of heat islands on human comfort and health . These include cardiopulmonary, vector-borne diseases and even death  . Heat stress is known to worsen cardiovascular, diabetic and respiratory conditions . In connection with the heat island effect, these people are also vulnerable to injuries and casualties due to increased thunderstorms, causing economic losses and other social problems .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report