Understanding spatiotemporal variation of heatwave projections across US cities

Area of Science:

• Environmental Science
• Climatology
• Public Health

Background:

• Heatwaves are a major meteorological hazard with severe health, environmental, and economic impacts.
• US heatwave frequency has risen from two per year in the 1960s to six per year in the 2010s.

Purpose of the Study:

• To assess past heatwave impacts in major US cities.
• To project future heatwave scenarios and analyze health/environmental consequences.
• To evaluate urban heatwave vulnerability considering climate and demographic shifts.

Main Methods:

• Investigated spatio-temporal variations of past heatwaves (intensity, frequency, duration).
• Projected future heatwave changes under various shared socioeconomic pathways (SSPs) until 2100.
• Examined heatwave impacts on human health and well-being using composite indices and demographic projections.

Main Results:

• Significant increases in heatwave frequency, intensity, and duration are projected across all US regions.
• Under high-emission scenarios, cities may experience 2-4 times more heatwave days annually by late 21st century.
• Night-time heatwaves could exceed half the year in some regions; southwestern and southern cities face severe heat stress.

Conclusions:

• Urban heatwave vulnerability is rising due to climatic and demographic changes.
• Proactive measures are crucial to address the escalating threat of heatwaves.
• The study provides a nuanced assessment for densely populated and high-risk urban areas.