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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.

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Earth & Climate News

December 21, 2025

Old military air samples turned out to be a treasure trove of biological DNA, allowing scientists to track moss spores over 35 years. The results show mosses now release spores up to a month earlier than in the 1990s. Even more surprising, the ...
New research reveals when glaciers around the world will vanish and why every fraction of a degree of warming could decide their ...
Much of the western U.S. is overdue for wildfire, with decades of suppression allowing fuel to build up across millions of hectares. Researchers estimate that 74% of the region is in a fire deficit, meaning far more land needs to burn to restore ...
Around 1,000 years ago, a major climate shift reshaped rainfall across the South Pacific, making western islands like Samoa and Tonga drier while eastern islands such as Tahiti became increasingly ...
Researchers analyzing ancient fossils from caves across Western Australia have uncovered a completely new species of bettong along with two new woylie subspecies—remarkable finds made bittersweet by signs that some may already be ...
New research shows that crops are far more vulnerable when too much rainfall originates from land rather than the ocean. Land-sourced moisture leads to weaker, less reliable rainfall, heightening drought risk. The U.S. Midwest and East Africa are ...
A sudden, unexplained mass die-off is decimating sea urchins around the world, including catastrophic losses in the Canary Islands. Key reef-grazing species are reaching historic lows, and their ability to reproduce has nearly halted in some ...
Fossils from Qatar have revealed a small, newly identified sea cow species that lived in the Arabian Gulf more than 20 million years ago. The site contains the densest known collection of fossil sea cow bones, showing that these animals once thrived ...
Researchers found that eroded lava rubble beneath the South Atlantic can trap enormous amounts of CO2 for tens of millions of years. These porous breccia deposits store far more carbon than previously sampled ocean crust. The discovery reshapes how ...
Scientists tracking young Arizona Bald Eagles found that many migrate north during summer and fall, bucking the traditional southbound pattern of most birds. Their routes rely heavily on historic stopover lakes and rivers, and often extend deep into ...
Researchers have uncovered surprising evidence that the deep ocean’s carbon-fixing engine works very differently than long assumed. While ammonia-oxidizing archaea were thought to dominate carbon fixation in the sunless depths, experiments show ...
Researchers discovered that unusually high temperatures can hinder early childhood development. Children living in hotter conditions were less likely to reach key learning milestones, especially in reading and basic math skills. Those facing ...

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