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The Himalayas stand as Earth’s highest mountain range, possibly the highest ever. How did it form? Why is it so tall? You might think understanding big mountain ranges requires big measurements – perhaps satellite imaging over tens or hundreds of thousands of square miles. Although scientists certainly use satellite data, many of us, including me, study the biggest of mountain ranges by relying on the smallest of measurements in tiny minerals that grew as the mountain range formed. These minerals are found in metamorphic rocks – rocks transformed by heat, pressure or both. One of the great joys in studying metamorphic rocks lies in microanalysis of their minerals. With measurements on scales smaller than the thickness of a human hair, we can unlock the age and chemical compositions hidden inside tiny crystals to understand processes occurring on a colossal scale. Measuring radioactive elements Minerals containing radioactive elements are of special interest...

New York City is poised to launch the first congestion pricing plan to reduce traffic in a major U.S. metropolitan area. Like many journeys in the Big Apple, this one has been punctuated by delays. Once the system starts up, however, it’s expected to significantly reduce gridlock in Manhattan and generate billions of dollars to improve public transit citywide. The basic idea is simple. To enter the Congestion Relief Zone, which covers Manhattan south of 60th Street, large trucks will pay $36, small trucks $24, passenger vehicles $15 and motorcycles $7.50. Ride-share vehicles and taxis will pay $2.50 and $1.25, respectively. Peak hours run from 5 a.m. to 9 p.m. on weekdays and 9 a.m. to 9 p.m. on weekends; overnight tolls are discounted by 75%. Evidence from cities around the world shows that charging motorists fees for driving into city centers during busy periods is a rarity in urban public policy: a measure that works and is cost-effective. Congestion pricing has succeed...

The U.S. power grid is the largest and most complex machine ever built. It’s also aging and under increasing stress from climate-driven disasters such as wildfires, hurricanes and heat waves. Over the past decade, power grids have played roles in wildfires in multiple states, including California, Hawaii, Oregon and Minnesota. When wind speeds are high and humidity is low, electrical infrastructure such as aboveground power lines can blow into vegetation or spark against other components, starting a fire that high winds then spread. Under extreme conditions, utilities may opt to shut off power to parts of the grid in their service areas to reduce wildfire risk. These outages, known as public safety power shutoffs, have occurred mainly in California, where wildfires have become larger and more destructive in recent decades. On April 5-6, 2024, Colorado utility Xcel Energy carried out that state’s first public safety power shutoff, cutting power to thousands of custo...

Wetlands have flourished along the world’s coastlines for thousands of years, playing valuable roles in the lives of people and wildlife. They protect the land from storm surge, stop seawater from contaminating drinking water supplies, and create habitat for birds, fish and threatened species. Much of that may be gone in a matter of decades. As the planet warms, sea level rises at an ever-faster rate. Wetlands have generally kept pace by building upward and creeping inland a few meters per year. But raised roadbeds, cities, farms and increasing land elevation can leave wetlands with nowhere to go. Sea-level rise projections for midcentury suggest the waterline will be shifting 15 to 100 times faster than wetland migration has been clocked. Many wetlands, like these on Cape Cod, are now bordered by human infrastructure, including towns and roads. Lance Cheung/USDA I have been studying coastal g...

The historic Paris climate agreement started a mantra from developing countries: “1.5 to stay alive.” It refers to the international aim to keep global warming under 1.5 degrees Celsius (2.8 Fahrenheit) compared with preindustrial times. But the world will likely pass that threshold within a decade, and global warming is showing little sign of slowing. The world is already facing natural disasters of epic proportions as temperatures rise. Heat records are routinely broken. Wildfire seasons are more extreme. Hurricane strength is increasing. Sea level rise is slowly submerging small island nations and coastal areas. The only known method able to quickly arrest this temperature rise is climate engineering. (It’s sometimes called geoengineering, sunlight reduction methods or solar climate intervention.) This is a set of proposed actions to deliberately alter the climate. These actions include mimicking the cooling effects of large volcanic eruptions by putting la...