Oceans & Climate

The Sun is our star, and it is the engine behind almost everything that happens on Earth. Its heat and light warm the land, the air, and the ocean.

The Sun does not warm every place the same. The ocean near the equator soaks up a lot of heat, like a giant bathtub of warm water. That warmth does not stay in one spot. The Sun's energy helps push ocean currents, which are like rivers inside the ocean, carrying warm water toward colder places. This spreads heat around the whole planet.

The Sun also drives weather. When sunlight warms the ocean's surface, some of the water turns into an invisible gas called water vapor and rises into the air. That is called evaporation. Later the water vapor cools into tiny drops and ice crystals, and falls as rain or snow.

Earth's atmosphere surrounds us with gases. It protects life and helps keep the planet warm enough for living things.

This air is arranged in layers. Our home is in the lowest one, where most clouds, rain, storms and winds occur.

Nitrogen and oxygen make up most of the atmosphere. Smaller amounts include water vapor and carbon dioxide. Even its small share of carbon dioxide helps retain heat.

Weather describes conditions at a particular time, such as rain on Tuesday. Climate describes a place's weather patterns over many years. A desert that stays dry year after year has a dry climate. Exchanges between the atmosphere and ocean help shape both weather and climate.

Sunlight supplies energy that passes through nature without being recycled. Matter, the material things contain, can be used again through cycles. Water and carbon both move this way.

Most water on Earth is in the ocean. Sunlight heats surface water, allowing some to evaporate into water vapor. As vapor cools, droplets or ice crystals can form clouds. Water returns as snow or rain and continues around the water cycle. The ocean is its largest water store.

The ocean also absorbs much carbon dioxide from the atmosphere. Tiny plant-like ocean organisms use this gas to make food. Removing some carbon dioxide from the air limits warming because excess carbon dioxide retains extra heat.

By storing large amounts of carbon and heat, oceans help moderate Earth's climate.

It is hard to imagine life on Earth without oceans. Ocean air and ocean water travel all around the planet, so the ocean helps shape the air you breathe and the rain that fills your taps. The ocean touches almost every part of your life, even if you live far from the beach.

The ocean is also home to an amazing community of living things, from tiny drifting plants to giant whales. A community of living things and their home is called an ecosystem.

But the ocean is feeling the heat. As people burn fuels that add carbon dioxide to the air, the planet warms up, and the ocean soaks up most of that extra heat. Ocean plants and animals are sensitive to temperature changes. Some must move to cooler water, and some struggle to survive.

That is why scientists say the ocean and the climate are partners. When we take care of the ocean, we help keep the whole planet's climate healthy.

Scientists keep careful track of how much carbon dioxide is in our air. For about 10,000 years the amount stayed fairly steady, and Earth's climate stayed steady too. But in the last couple of hundred years, the amount has shot up fast, higher than it has been in millions of years.

Why does that matter? Carbon dioxide traps heat, like a blanket around the planet. More of it means a warmer Earth. And the ocean, which covers most of our planet, soaks up a huge share of that extra heat and extra carbon dioxide.

In the Pacific Ocean, people are already seeing changes. The water is getting warmer, sea levels are rising, and storms can grow stronger. Island communities that have lived by the sea for countless generations are watching their shores change.

The good news is that understanding the ocean and climate connection helps us protect both. The ocean has been taking care of us. Now it needs us to take care of it.