A global study has found that heat stress is intensifying worldwide, with some areas experiencing up to two more months of heat stress than in the 1970s. The study suggests that longer and hotter heatwaves are contributing to the rise in heat stress, which is affecting a significant portion of the global population. Estimates vary, but it is reported that around 1 billion more people face extreme heat stress at night and approximately 22% of the world's population is affected by extreme heat stress.