Ocean currents and carbon dioxide content

Changes in ocean currents

Ocean currents carry heat around the Earth. As the oceans absorb more heat from the atmosphere, sea surface temperature increases and the ocean circulation patterns that transport warm and cold water around the globe change. The direction of these currents can shift so that different areas become warmer or cooler. As oceans store a large amount of heat, even small changes in ocean currents can have a large effect on global climate. In particular, increases in sea surface temperature can increase the amount of atmospheric water vapour over the oceans, increasing the quantity of greenhouse gas. If the oceans are warmer they can’t absorb as much carbon dioxide from the atmosphere.

Carbon dioxide content of the oceans

The oceans contain more CO2 in total than the atmosphere and exchanges in CO2 occur between the oceans and the atmosphere. CO2 absorbed in ocean water does not trap heat as it does in the atmosphere. The world’s oceans absorb about a quarter of the CO2 we release into the atmosphere every year. As atmospheric CO2 levels increase so do the ocean’s CO2 levels.

Ocean currents during the cretaceous. BGS © UKRI

Ocean currents present day. BGS © UKRI