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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 12, 2025

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 ...
Scientists discovered a small protein region that determines whether plants reject or welcome nitrogen-fixing bacteria. By tweaking only two amino acids, they converted a defensive receptor into one that supports symbiosis. Early success in barley ...
A newly analyzed set of climate data points to a major volcanic eruption that may have played a key role in the Black Death’s arrival. Cooling and crop failures across Europe pushed Italian states to bring in grain from the Black Sea. Those ...
A century-old North Atlantic cold patch is now linked to a long-term slowdown in the AMOC, the climate-regulating conveyor belt of ocean water. Only weakened-AMOC models match observed temperature and salinity patterns, overturning recent model ...
This year’s ozone hole over Antarctica ranked among the smallest since the early 1990s, reflecting steady progress from decades of global action under the Montreal Protocol. Declining chlorine levels and warmer stratospheric temperatures helped ...
As the last Ice Age waned and the Holocene dawned, deep-ocean circulation around Antarctica underwent dramatic shifts that helped release long-stored carbon back into the atmosphere. Deep-sea sediments show that ancient Antarctic waters once trapped ...
Dolichospermum, a type of cyanobacteria thriving in Lake Erie’s warming waters, has been identified as the surprising culprit behind the lake’s dangerous saxitoxins—some of the most potent natural neurotoxins known. Using advanced genome ...

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