environment

Light pollution has steadily intensified and expanded from urban areas, and with the advent of LED lighting, it is growing in North America by up to 10% per year, as measured by the visibility of stars in the night sky. In our recent study, we found that the glow from cities and urban outskirts can powerfully attract migratory birds, drawing them into developed areas where food is scarcer and they face threats such as colliding with glass buildings. Each spring and fall, migratory birds journey to or from their breeding grounds, sometimes traveling thousands of miles. En route, most birds need to make stopovers to rest and feed. Some species burn off half of their body mass during migration. Migratory stopover sites are not random, and birds typically use the same locations from year to year. Because migration takes place on a continental scale, with billions of birds crossing North America each migratory season, it’s important for scientists to understand what attracts bi...

A lot can go wrong in a large urban water system. Pumps malfunction. Valves break. Pipes leak. Even when the system is functioning properly, water can sit in pipes for long periods of time. Water shortages are also a growing problem in a warming world, as communities across the Southwestern U.S. and in many developing nations are discovering. That’s why cities have started experimenting with small-scale alternatives – including wastewater recycling and localized water treatment strategies known as decentralized or distributed systems. I study large- and small-scale water systems, focusing on innovative system designs that allow local use of water sources that might otherwise go to waste. As technology improves, cities are discovering something that rural communities have long known: Small-scale water treatment, properly engineered, can be cheaper and easier to maintain than a centralized system, and it can improve water security and even the environment. Cleaning w...

Tropical forest landscapes are home to millions of Indigenous peoples and small-scale farmers. Just about every square meter of land is spoken for, even if claims are not formally recognized by governments. These local landholders hold the key to a valuable solution as the world tries to slow climate change – restoring deforested tropical landscapes for a healthier future. Tropical forests are vital to Earth’s climate and biodiversity, but a soccer field-size area of mature tropical forest is burned or cut down about every 5 seconds to clear space for crops and cattle today. While those trees may be lost, the land still has potential. Tropical forests’ combination of year-round sunshine and high rainfall can lead to high growth rates, suggesting that areas where tropical forests once grew could be valuable sites for reforestation. In fact, a host of international agreements and declarations envision just this. The Worl...

On a recent research trip to China, I wandered through the Oasis Mall in suburban Shanghai. Like many Chinese shopping centers, this complex was filled with empty stores that reflected the end of China’s 30-year-long economic expansion. But there also were surprises. Along a stretch of the mall’s interior walkway, a cluster of parents and grandparents sat on chairs. They were looking through a plate glass window, watching a dozen 5- to 7-year-old girls practice ballet steps, carefully following their teacher’s choreography. A space initially designed for retail had been turned into a dance studio. From 1990 through 2020, large, shiny shopping malls embodied China’s spectacular economic growth. They sprouted in cities large and small to meet consumer demand from an emerging middle class that was keen to express its newfound affluence. These centers look familiar to American eyes, which isn’t surprising: U.S. architectural firms built 170 malls in Ch...

Regardless of how you celebrate end-of-year holidays, food is probably central to your winter festivities. And a trio of spices – cinnamon, nutmeg and ginger – feature in many dishes and drinks and are an unmistakable part of the scent profile we associate with the holiday season. As a plant scientist, I was curious to know how these spices, grown in the tropics, became so closely associated with the Northern Hemisphere’s winter holidays. Just as cranberries’ fall harvest makes them a natural choice for Thanksgiving, I thought that perhaps the seasonality of spice harvest had something to do with their use during the winter months. However, this doesn’t appear to be the case. When it comes to growing spices, producers are playing the long game. Spices are prized commodities that have fueled global trade, exploration and conquest for centuries. Growing holiday spices Take ginger, which features in both sweet a...