How Climate Works
Part of Hall of Planet Earth.
Ice also reflects incoming sunlight, cooling the poles even more. The temperature difference sets the ocean and atmosphere in motion as they work together to distribute heat around the planet. Movement of heat by the atmosphere and ocean gives rise to climate and weather.
Weather or Climate?
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We experience weather every day and even moment-to-moment. It’s why you choose to wear a T-shirt, sweater or raincoat. Climate is the average weather over decades or longer. How people build their homes and what crops they grow are usually determined by climate.
House, Paulo Oliveira/Alamy; person with umbrella, Shutterstock
Components of the Climate System
Earth’s climate system is like a body: it relies on many interrelated pieces working together to function.
Cryosphere (snow and ice): Cools Earth by reflecting incoming sunlight, limiting how much heat is absorbed by the surface.
Atmosphere (air): Insulates Earth by trapping heat and transporting heat and water vapor.
Lithosphere (solid earth): Absorbs solar energy, radiates heat and stores carbon; continents and landforms help direct ocean and wind currents.
Biosphere (living things): Organisms take up carbon and exchange it with the atmosphere and ocean.
Hydrosphere (water): The ocean absorbs heat and carbon, transports them around the planet and naturally controls atmospheric CO 2.
How Does the Ocean Control Climate?
The ocean holds 50 times more CO2 and 1,000 times more heat than the atmosphere.
The atmosphere moderates Earth’s temperature through heat-trapping greenhouse gases, mainly carbon dioxide (CO2). But the ocean is also crucial to climate. It acts as a control knob, absorbing or releasing carbon and heat in response to changes in the atmosphere. It will take thousands of years for the ocean to absorb the excess CO2 in today’s atmosphere.
Changing the Carbon Cycle
The carbon cycle has regulated CO2 levels in Earth’s atmosphere for billions of years. How is human activity changing the cycle?
Burning fossil fuels releases carbon that has been stored underground for millions of years, instantly adding it to the atmosphere as CO2. It will take thousands of years for the natural cycle to return this carbon to the rock reservoir.
Carbon constantly moves between the ocean, atmosphere, biosphere and other components of the climate system. The natural exchange of carbon between these components, called reservoirs, regulates CO2 in the atmosphere, thereby stabilizing Earth’s temperature. Burning fossil fuels releases carbon into the atmosphere more rapidly than natural processes can remove it, disrupting the balance of the carbon cycle.
CO2 = carbon dioxide o=C=o
The Reason for the Seasons
Earth has seasons because its axis of spin is tilted (see diagram). This causes the amount of solar energy warming each hemisphere to shift based on where the planet is in its yearly orbit.