Smithsonian National Museum of Natural History Virtual Tour

Carbon affects Earth's climate and life. Carbon is in the Earth's: crust's deep layers, soil, and ocean. carbon is also in the air as the planet-warming gas carbon dioxide. Carbon is in all living things, including us! Our planet is like a great carbon machine, moving carbon around in an endless cycle... Plants pull carbon out of the air to grow. Animals get carbon by eating plants or other animals. Dead plants and animals leave carbon in the soil. When they decay, most of their carbon soon returns to the air. In the same way, carbon also moves rapidly between the air and ocean... But carbon accumulates in the Earth very slowly as dead animals and plants become fossil fuels like coal and oil. As rocks weather, carbon moves from the air to the ocean where it combines with calcium dissolved in water and forms limestone. Volcanism returns it to the atmosphere as rocks are heated deep in the Earth over millions of years. This machine has chugged along with nearly balanced flows, for tens of millions of years. Until fossil fuels... About 150 years ago when we began to mine fossil carbon and burn it for energy. Today, we release carbon into the air more than 100 times faster than natural processes return it to the Earth. Farming and cutting forests also add carbon to the atmosphere. So, carbon is rapidly building up in the atmosphere—faster than ever before in Earth’s history. Natural processes will take many thousands of years to remove the excess carbon from the air. More carbon in the atmosphere warms to climate, making life hard for many species—including us. Excess carbon also makes the ocean more acidic, threatening marine ecosystems and raising sea levels. It’s up to us to stop our carbon emissions to rebalance the cycle and preserve our quality of life.