Climate change

To get a sense of the enormous amount of water atmospheric rivers dumped on the Western U.S. this year and the magnitude of the flood risk ahead, take a look at California’s Central Valley, where about a quarter of the nation’s food is grown. This region was once home to the largest freshwater lake west of the Rockies. But the rivers that fed Tulare Lake were dammed and diverted long ago, leaving it nearly dry by 1920. Farmers have been growing food on the fertile lake bed for decades. This year, however, Tulare Lake is remerging. Runoff and snowmelt from the Sierra Nevada have overwhelmed waterways and flooded farms and orchards. After similar storms in 1983, the lake covered more than 100 square miles, and scientists say this year’s precipitation is looking a lot like 1983. Communities there and across the West are preparing for flooding and mudslide disasters as record snow begins to melt. Tulare Lake, long dry, begi...

A 23-year western drought has drastically shrunk the Colorado River, which provides water for drinking and irrigation for Wyoming, Colorado, Utah, New Mexico, Arizona, Nevada, California and two states in Mexico. Under a 1922 compact, these jurisdictions receive fixed allocations of water from the river – but now there’s not enough water to provide them. As states try to negotiate ways to share the decreasing flow, the U.S. Department of the Interior is considering cuts of up to 25% in allotments for California, Nevada and Arizona. The federal government can regulate these states’ water shares because they come mainly from Lake Mead, the largest U.S. reservoir, which was created when the Hoover Dam was built on the Colorado River near Las Vegas. These five articles from The Conversation’s archive explain what’s happening and what’s at stake in the Colorado River basin’s drought crisis. The Colorado River prov...

One big question keeps surfacing after the Biden administration announced plans to raise auto standards so sharply they would likely boost electric vehicle production to 67% of all new passenger vehicle sales in under a decade: Can automakers pull that off? The proposal would require a huge change in production and consumer choice. To put it in perspective, in 2022 about 6% of U.S. passenger vehicle sales were all-electric. I study the electric vehicle industry and policy. Here’s why I think the Environmental Protection Agency’s plan can succeed. Automakers have met tough targets before Automakers typically push back against tougher rules and often lobby to get standards relaxed. However, U.S. car companies have also shown that they can meet ambitious goals. When California began requiring that car companies sell a certain percentage of zero-emissions vehicles, its initial target translated to about 15% of all new car sales by 2025. Automakers quickly exceeded tha...

Home runs are exhilarating – those lofting moments when everyone looks skyward, baseball players and fans alike, anxiously awaiting the outcome: run or out, win or loss, elation or despair. Over the past several Major League Baseball seasons, home run numbers have climbed dramatically, including Aaron Judge’s record-breaking 62 homers for the New York Yankees in 2022. Baseball analysts have pointed to many different factors for this surge, from changes in baseball construction to advances in game analytics. Our study, published April 7, 2023, offers solid evidence for another cause – rising global temperatures. What we learned from 100,000 baseball games The physics tell a simple and compelling story: Warm air is less dense than cool air. As air heats up and molecules move faster, the air expands, leaving more space between molecules. As a result, a batted ball should fly farther on a warmer day than it would on a cooler day owing to less air resistance. Th...

As wildfire risk rises in the West, wildland firefighters and officials are keeping a closer eye on the high mountains – regions once considered too wet to burn. The growing fire risk in these areas became startling clear in 2020, when Colorado’s East Troublesome Fire burned up and over the Continental Divide to become the state’s second-largest fire on record. The following year, California’s Dixie Fire became the first on record to burn across the Sierra Nevada’s crest and start down the other side. We study wildfire behavior as climate scientists and engineers. In a new study, we show that fire risk has intensified in every region across the West over the past four decades, but the sharpest upward trends are in the high elevations. In 2020, Colorado’s East Troublesome fire jumped the Continental Divide. AP Photo/David Zalubowski High mountain fires can create...