4. A Review of the Health Sector Impacts of 4 °C or more Temperature Rise

Threat of extreme warming on human health poses risks worldwide. The impacts of extreme warming on human health can be direct and indirect, and depends on other problems already existing in the region. To evaluate the impacts of warming above 4 °C on human health, a narrative review was carried out with studies and reports on the potential consequences of a high heating in human health in Brazil. The main direct and indirect impacts on human health and sociodemographic and economic vulnerability were considered in this review. The heat stress was most relevant direct effect; this condition is characterized by continuous maximum temperatures above 37 °C and high air humidity that difficult the heat loss through sweating by human body intensifying the well-known risks of heat-related illnesses and limit workers’ productivity, specially in the North and Midwest region. In addition, the raise the average temperature above 4 °C at the end of the century may increase the intensity and frequency of droughts with human health effects associated with the unavailability of treated water such as increased gastroenteritis and hepatitis A. For this same scenario and period, the municipalities of the North, Northeast, Southeast and South regions will present even more favorable thermal conditions for the spread of Aedes aegypti increasing the potential of dissemination of vector diseases such as dengue fever, chikungunya and zika virus. This study provide evidence that extreme temperatures have the potential to impact on human health of the Brazilian population, especially those who are more vulnerable socially and economically.