New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Carbon dioxide

Carbon dioxide is a chemical compound composed of one carbon and two oxygen atoms. It is often referred to by its formula CO2. It is present in the Earth's atmosphere at a low concentration and acts as a greenhouse gas. In its solid state, it is called dry ice. It is a major component of the carbon cycle.

Atmospheric carbon dioxide derives from multiple natural sources including volcanic outgassing, the combustion of organic matter, and the respiration processes of living aerobic organisms; man-made sources of carbon dioxide come mainly from the burning of various fossil fuels for power generation and transport use. It is also produced by various microorganisms from fermentation and cellular respiration. Plants convert carbon dioxide to oxygen during a process called photosynthesis, using both the carbon and the oxygen to construct carbohydrates. In addition, plants also release oxygen to the atmosphere, which is subsequently used for respiration by heterotrophic organisms, forming a cycle.

Related Stories
 


Earth & Climate News

November 13, 2025

Arctic sea ice is disappearing fast, and scientists have turned to an unexpected cosmic clue—space dust—to uncover how ice has changed over tens of thousands of years. By tracking helium-3–bearing dust trapped (or blocked) by ancient ice, ...
Researchers discovered that living horsetails act like natural distillation towers, producing bizarre oxygen isotope signatures more extreme than anything previously recorded on Earth—sometimes resembling meteorite water. By tracing these isotopic ...
Researchers discovered that continents don’t just split at the surface—they also peel from below, feeding volcanic activity in the oceans. Simulations reveal that slow mantle waves strip continental roots and push them deep into the oceanic ...
Researchers from the University of Vienna discovered MISO bacteria that use iron minerals to oxidize toxic sulfide, creating energy and producing sulfate. This biological process reshapes how scientists understand global sulfur and iron cycles. By ...
In Death Valley’s relentless heat, Tidestromia oblongifolia doesn’t just survive—it thrives. Michigan State University scientists discovered that the plant can quickly adjust its photosynthetic machinery to endure extreme temperatures that ...
Around 9,000 years ago, East Antarctica went through a dramatic meltdown that was anything but isolated. Scientists have discovered that warm deep ocean water surged beneath the region’s floating ice shelves, causing them to collapse and ...
Scientists have discovered that deep-sea mining plumes can strip vital nutrition from the ocean’s twilight zone, replacing natural food with nutrient-poor sediment. The resulting “junk food” effect could starve life across entire marine ...
A new study shows that the Southern Ocean releases far more carbon dioxide in winter than once thought. By combining laser satellite data with AI analysis, scientists managed to “see” through the polar darkness for the first time. The results ...
Researchers warn Antarctica is undergoing abrupt changes that could trigger global consequences. Melting ice, collapsing ice shelves, and disrupted ocean circulation threaten sea levels, ecosystems, and climate stability. Wildlife such as penguins ...
A new copper-magnesium-iron catalyst transforms CO2 into CO at low temperatures with record-breaking efficiency and stability. The discovery paves the way for affordable, scalable production of carbon-neutral synthetic ...
Scientists discovered 6-million-year-old ice in Antarctica, offering the oldest direct record of Earth’s ancient atmosphere and climate. The finding reveals a dramatic cooling trend and promises insights into greenhouse gas changes over millions ...
When Surtsey erupted from the sea in 1963, it became a living experiment in how life begins anew. Decades later, scientists discovered that the plants colonizing this young island weren’t carried by the wind or floating on ocean currents, but ...

Latest Headlines

updated 12:56 pm ET