The phenomenon of heat stress refers to heat received in excess of that which the body can tolerate without physiological impairment. It is one of the major consequences of global warming. By 2030, the equivalent of more than 2 per cent of total working hours worldwide is projected to be lost every year, either because it is too hot to work or because workers have to work at a slower pace. This report shows the impact of heat stress on productivity and decent work for virtually all countries in the world. It presents innovative solutions based on social dialogue to promote occupational safety and health for the most vulnerable groups of workers.