Extreme Weather and Climate Change

Heat Waves

A warmer baseline shifts the temperature distribution, making rare heat events common. Once-per-decade events now occur three times per decade; at 2 degrees warming, 5.6 times. The 2021 Pacific Northwest heat dome was found virtually impossible without climate change (150x more likely). Urban heat islands amplify exposure by 5-10 degrees. Extreme heat kills more people than any other weather hazard in many countries.

Heavy Precipitation

Clausius-Clapeyron dictates about 7 percent more moisture per degree of warming. Extreme precipitation has intensified at approximately this rate globally. Some events exceed expectations through dynamical feedbacks where latent heat release invigorates updrafts. Atmospheric rivers are projected to intensify, increasing flood risk.

Drought and Wildfire

Higher temperatures increase evaporative demand, drying soils even without precipitation changes. Western US burned area has roughly doubled since the 1980s. Fire seasons extend by months. Attribution found climate change increased extreme fire weather likelihood by 30+ percent during Australia's 2019-2020 Black Summer.

Tropical Cyclones

Total numbers unchanged, but more reach Category 4-5. Rapid intensification more frequent. Rainfall rates up 10-15 percent. Slower movement increases local totals. Sea level rise elevates storm surge baselines, potentially doubling dangerous flood frequency along many coasts.

Attribution Science

Event attribution compares event probability in current versus pre-industrial climate using model ensembles. Analyses now published within days of events by World Weather Attribution, quantifying human influence on specific disasters for risk communication and adaptation planning.