The Carbon Dioxide Loop

The oceans are great at absorbing carbon dioxide (CO2) from the air, but when their deep waters are brought to the surface, the oceans themselves can be a source of this prevalent greenhouse gas.Wind patterns together with the Earth’s rotation drive deep ocean water — and the CO2 it sequesters — upward, replacing surface water moving offshore. A process known as upwelling, it occurs on the west coasts of continents. And it’s part of a never-ending loop in which