Oceans are a global force of nature that form the foundation of the blue planet on which we live. They cover 71% of our planet’s surface and make up 95% of all the space available to life. They are a life-support system for Earth and a global commons that provide us with free goods and services, from the food we eat to the oxygen we breathe.
The oceans also regulate the global climate; they mediate temperature and drive the weather, determining rainfall, droughts, and floods. They are also the world’s largest store of carbon, where an estimated 83% of the global carbon cycle is circulated through marine waters.
But the interaction between these two natural forces is altering, and the exchange is intensifying. We’re seeing the consequences of this around the world. In the last 200 years, the oceans have absorbed a third of the CO2 produced by human activities and 90% of the extra heat trapped by the rising concentration of greenhouse gases.
As the climate responds to decades of increasing carbon emissions, the store of energy and heat from the atmosphere builds up in the ocean. If we reach a tipping point, we will likely see more extreme weather events, changing ocean currents, rising sea levels and temperatures, and melting of sea ice and ice sheets—all of which aggravate the negative impacts of overfishing, illegal fishing, pollution, and habitat degradation.