Why climate change worsens heatwaves, droughts, fires and floods worldwide

Heat extremes grow stronger

Even a small rise in average temperatures can make heat extremes significantly worse. Scientists compare computer simulations of an event in two scenarios to estimate how much climate change influenced a particular heatwave, storm or drought.

The World Weather Attribution group says climate change intensified multiple heatwaves around the world this year. Heat domes, formed when high pressure lingers and traps hot air, can also bring prolonged periods of extreme heat.

Rainfall brings risks

A warmer atmosphere can hold about 7% more moisture for every 1C increase in air temperature. The IPCC says human activity has made heavy rainfall more frequent and intense across most land regions.

Researchers at World Weather Attribution found climate change increased extreme rainfall associated with a storm by 16%. In the UK, winters from 2016 to 2025 were 13% wetter than in the period from 1961 to 1990, the Met Office says.

Drought patterns shift

Climate change is shifting rainfall patterns, leaving some parts of the world wetter and others drier. The resulting water shortages can increase the risk of drought, although connecting climate change to a specific drought can be difficult because many factors affect water availability.

Conditions fuel wildfires

The IPCC says climate change is making weather conditions that help wildfires spread more likely. Dry vegetation supplies fuel, and fires can move quickly, especially when winds are strong.

More than 5,000 wildfires burned across Canada this summer, contributing to some of the world’s worst air quality in nearby cities. In January 2026, wildfires in Chile forced more than 50,000 people to evacuate.