Globally, 2023 was the warmest year on record and 2014 to 2023 was the warmest decade on record since thermometer-based observations began. The incidence of heat waves, coastal flooding, wildfires and other trends associated with an altered climate appears to be on the uptick. These and other key indicators of climate change in the U.S. are updated in a new report from the U.S. Environmental Protection Agency (EPA).

The fifth edition of Climate Change Indicators in the United States explores historical and new data reflecting evidence that climate change is increasingly affecting people’s health, society and ecosystems.

Heat waves are occurring more frequently and lasting longer in U.S. urban areas. Their occurrence has increased from an average of two heat waves per year during the 1960s to six per year during the 2010s and 2020s. From 1992 to 2022, a total of 986 workers across all industry sectors in the U.S. died from exposure to heat. The construction sector accounted for about 34%, or 334, of all occupational heat-related deaths.

Sea surface temperatures continue to rise and the annual cumulative intensity of marine heat waves has increased in most coastal U.S. waters during 1982 to 2023. The largest changes were observed in waters off the northeastern U.S. and Alaskan coasts.

During 1982 to 2023, the snowpack season became shorter at 80% of the sites measured. Across all sites, the length of the snowpack season decreased by an average of about 15 days and peak snowpack has shifted earlier by an average of nearly seven days since 1982.

Tidal flooding is becoming more frequent along the U.S. coastline. Most sites with long-term data experienced an increase in tidal flooding since the 1950s. At more than half of these sites, floods are now at least five times more common than they were in the 1950s. The rate of increase of flood events per year is largest at most locations in Hawaii, and along the East and Gulf coasts.