Mercury is released by environmental and human-driven processes. Some forms, specifically methylmercury, are toxic to humans.

Atmospheric CO₂ concentrations are surging, even as emissions level out. Natural carbon sinks are showing signs of faltering ...

Across the globe, monsoon rainfall switches on in spring and off in autumn. Until now, this seasonal pattern was primarily understood as an immediate response to changes in solar radiation. A new ...

Hundreds of millions of years before oxygen surged in the atmosphere 2.4 billion years ago, swaths of oxygen winked in and out of existence in the ocean.