Climate change

Summer 2023 was the hottest on record by a huge margin. Hundreds of millions of people suffered as heat waves cooked Europe, Japan, Texas and the Southwestern U.S. Phoenix hit 110 degrees Fahrenheit (43 degrees Celsius) for a record 54 days, including a 31-day streak in July. Large parts of Canada were on fire. Lahaina, Hawaii, burned to the ground. As an atmospheric scientist, I get asked at least once a week if the wild weather we’ve been having is “caused” by climate change. This question reflects a misunderstanding of the difference between weather and climate. Consider this analogy from the world of sports: Suppose a baseball player is having a great season, and his batting average is twice what it was last year. If he hits a ball out of the park on Tuesday, we don’t ask whether he got that hit because his batting average has risen. His average has gone up because of the hits, not the other way around. Perhaps the Tuesday homer resulted from a fat...

Canada’s seemingly endless wildfires in 2023 introduced millions of people across North America to the health hazards of wildfire smoke. While Western states have contended with smoky fire seasons for years, the air quality alerts across the U.S. Midwest and Northeast this summer reached levels never seen there before. The smoke left the air so unhealthy in Philadelphia on June 7, 2023, that the Phillies-Detroit Tigers Major League Baseball game was postponed. That same week, New York City residents hunkered down indoors for several days as a smoky haze hung over the city, turning the skies orange and exposing millions of people to the worst air quality in the world. Smoke also drifted into the Midwest, triggering the highest air quality index levels in the Chicago area in at least 24 years, forcing the cancellation of numerous summer activities and leaving residents with raspy voices. In several states, people woke up to smoky skies day after day....

Images of orange groves and Spanish-themed hotels with palm tree gardens filled countless pamphlets and articles promoting Southern California and Florida in the late 19th century, promising escape from winter’s reach. This vision of an “American Italy” captured hearts and imaginations across the U.S. In it, Florida and California promised a place in the sun for industrious Americans to live the good life, with the perfect climate. But the very climates that made these semitropical playgrounds the American dream of the 20th century threaten to break their reputations in the 21st century. A postcard illustrates the latest style for Miami beach bathing around 1920. Asheville Post Card Co./Wikimedia In California, home owners now face dangerous heat waves, extended droughts that threaten the water supply, and uncontrollable wildfires. In Florida, sea level rise is worsening the risks...

The U.S. government is investing over US$7 billion in the coming years to try to manage the nation’s escalating wildfire crisis. That includes a commitment to treat at least 60 million acres in the next 10 years by expanding forest-thinning efforts and controlled burns. While that sounds like a lot – 60 million acres is about the size of Wyoming – it’s nowhere close to enough to treat every acre that needs it. So, where can taxpayers get the biggest bang for the buck? I’m a fire ecologist in Montana. In a new study, my colleagues and I mapped out where forest treatments can do the most to simultaneously protect communities – by preventing wildfires from turning into disasters – and also protect the forests and the climate we rely on, by keeping carbon out of the atmosphere and stored in healthy soils and trees. Wildfires are becoming more severe Forests and fires have always been intertwined in the West. Fires in dry conifer forests...

On a recent visit to Rangely, a small town in northwest Colorado, my colleagues and I met with the administrators of a highly regarded community college to discuss the town’s economy. Leaving the scenic campus, we saw families driving into the mountains in off-road vehicles, a favorite activity for this outdoors-loving community. With a median household income above US$70,000 and a low cost of living, Rangely does not have the signs of a town in economic distress. But an existential risk looms over Rangely. The town is here because of an oil boom during World War II. Today, the oil and gas industry contributes over half of the county’s economic output. Rangely is not unique in the United States, which is the world’s largest producer of oil and natural gas. There are towns across the country that depend on the oil and gas industry for well-paying jobs and public revenues that fund their schools and other critical services. A heavy dependence on any single indus...