Same-day heat wave and wildfire smoke exposure is increasing worldwide
Europe's heat waves this past summer broke countless records, and wildfires spread across Spain and France, forcing mass evacuations.
A 20-year study reveals that the number of people exposed to both wildfires and heat waves globally on the same days has increased by 287 million over the two decades from 2000 to 2019, and that over half of the world's population has experienced these conjoined weather events over the 20 years.
The authors of the study—from Monash University in Melbourne, Australia—warn that this exposure, and the resulting cardiovascular and respiratory illnesses, will continue to increase as climate warming leads to more combined heat waves and wildfires. The study investigated the global spatial, temporal and sociodemographic distribution of exposure to both heat waves and wildfires.
The study, led by Dr. Yao Wu and professors Yuming Guo and Shanshan Li from Monash University and published in the journal Science Advances, found that more than half (52.4%) of those in populated areas—and almost 56% of all people worldwide—experienced increasing exposure to these combined weather events.
The study also found that 916 million people each year experienced at least one co-exposure day (i.e., exposure to both heat waves and wildfire pollution on the same day).
Respiratory and cardiovascular health risks from landscape fire-related air pollution are amplified during stretches of extreme temperatures.
The global annual average co-exposure was 1.3 days per person, rising from one day in 2000–2009 to 1.7 days in 2010–2019. During the study period, the top five countries with the highest annual averages of person-days of co-exposure to heat waves and landscape fire smoke pollution were the Democratic Republic of the Congo, Indonesia, Mexico, Brazil and the Russian Federation.