Photo of the Day 364

Thermal Vent, New Zealand, 2004

Photograph by Peter Essick

Scientists believe that forests, grasslands, and the waters of the oceans act as carbon sinks—stealing back roughly half of the carbon dioxide we humans emit, slowing its buildup in the atmosphere and delaying its effects on climate.

Eons pass before carbon, buried in the Earth's crust, issues as a gas from a volcanic vent in New Zealand (above), or locked up in limestone, erodes off mountains. Carbon cycles faster when decaying from a leaf or traveling as wind-tossed pollen.

(Text adapted from and photo shot on assignment for, but not published in, "The Case of the Missing Carbon," February 2004, National Geographic magazine)