North America is facing a double threat from climate change: dangerous heat and heavy wildfire smoke. These twin hazards have sickened people across the continent and caused widespread damage to crops, infrastructure and ecosystems.
According to the National Oceanic and Atmospheric Administration, June 2021 was the hottest June on record for the contiguous United States, with an average temperature of 22.6 degrees Celsius, 2.9 degrees above the 20th-century average. Canada also experienced record-breaking heat waves, especially in the western provinces, where temperatures soared above 40 degrees Celsius in some places.
The extreme heat has fueled wildfires that have burned millions of acres of land in both countries, sending plumes of smoke across vast distances. The smoke contains fine particles that can penetrate deep into the lungs and cause respiratory problems, cardiovascular diseases and premature death. According to a study by researchers at Harvard University and Columbia University, smoke pollution from wildfires in the western United States was responsible for an estimated 19,700 deaths in 2020.
The smoke also affects visibility, air quality and climate. It can block sunlight, reduce solar radiation and lower surface temperatures. It can also interact with clouds and aerosols, altering precipitation patterns and creating feedback loops that can intensify or prolong droughts.
Scientists are using satellite data and computer models to trace the origin and trajectory of smoke plumes and to predict their health impacts. They are also developing early warning systems and disaster relief programs to help people cope with the effects of heat and smoke.
Climate change is expected to increase the frequency, intensity and duration of heat waves and wildfires in North America, posing serious challenges for public health, economic development and environmental conservation. Experts say that reducing greenhouse gas emissions, enhancing adaptation measures and increasing international cooperation are essential to mitigate the risks and build resilience.
