The surface ocean plays a critical role in the global carbon cycle, absorbing approximately one quarter of the carbon dioxide emitted to the atmosphere from the burning of fossil fuels, deforestation, and other human activities. As more and more anthropogenic CO2 has been emitted into the atmosphere,
the ocean has absorbed greater amounts at increasingly rapid rates. In the absence of this service by the oceans, atmospheric CO2 levels would be significantly higher than at present and the effects of global climate change more marked.