Across international and US campuses, a new sustainability trend is taking root: “swap shops” and free stores, designed to reduce dorm-room waste while easing students’ financial burdens.

In the struggle against climate change, it’s easy to wish for some technology—or even magic!—that could remove Earth-warming carbon dioxide (CO2) from the atmosphere and turn it into something useful. But this mechanism already exists and is much older than the climate changes of the past two centuries.

On a chilly morning in Zurich, commuters rush through the humming arteries of the city’s underground train system. Unbeknownst to them, the air shimmering behind the tiled tunnel walls holds a secret: Beneath their feet and beyond the blaring trains, the Earth is offering up energy.

The detached single-family home on a spacious suburban lot has long symbolized American prosperity. But as development sprawls further outward—consuming farmlands, wetlands, and forests—environmental costs climb: Low-density, car-centric housing developments are a key driver of carbon emissions, land degradation, and biodiversity loss.

The world's food supply has relied on conventional farming for the best part of a century. But its extensive use of pesticides, herbicides, and fertilizers is having an impact on greenhouse gases, biodiversity and possibly human health.