evidence: What role do the oceans play in regulating the climate and supporting life on Earth? [...] The oceans are a major component of the climate system. They have played the principal role in the climatic balance that the planet has experienced over the last few thousand years. Their role in regulating climate involves taking up heat and redistributing it across the globe, increasing atmospheric humidity, and buffering (taking up and storing) large quantities of CO2 from the atmosphere. The oceans are by far the largest active carbon reservoir on the planet, storing about 38,000 billion tonnes of carbon. By comparison, this is over 28 times more than the quantity of carbon stored by land vegetation and atmosphere combined. [...] The ocean is also crucial in controlling atmospheric temperatures: without the ocean and its diversity of service provision, Earth’s maximum temperature would exceed 100°C, and the average surface temperature, which is currently around 15°C, would instead be around 50°C. Unfortunately, the excess heat absorbed by the oceans has increased their mean temperature in recent decades and this warming is contributing to the melting of icesheets and glaciers as the oceans redistribute heat towards the poles – and in turn, to sea level rise. (This is detailed further in our explainer on the oceans and climate change.)