The Intergovernmental Panel on Climate Change defines an extreme weather event as one that is rare at a particular place and time of year. This rarity typically means the event occurs as rarely as the 10th or 90th percentile of a probability density function estimated from observations.
The European heat waves from summer 2003 caused an estimated 30,000 excess deaths due to heat stress and air pollution. During excessive heat, plants shut their leaf pores to conserve water, leaving more ozone in the air and leading to higher mortality rates.
The worst heat wave in the United States occurred in 1936 and killed more than 5,000 people directly. Australia suffered its worst heat wave between 1938 and 1939, resulting in 438 fatalities.
In 2020, the National Oceanic and Atmospheric Administration predicted that the frequency of tropical storms would decline by 25 percent over the 21st century while their maximum intensity would rise by 5 percent.
The highest economic losses occurred in 2005, the year of Hurricane Katrina. In 2011 the IPCC estimated that annual losses have ranged since 1980 from a few billion to above US$200 billion.
On the 23rd of July 2020, Munich Re announced that 2,900 total global deaths from natural disasters for the first half of 2020 were a record-low. The death toll from natural disasters has declined over 90 percent since the 1920s even as the total human population quadrupled.