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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 9, 2025

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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 ...
Two decades of satellite and GPS data show the Thwaites Eastern Ice Shelf slowly losing its grip on a crucial stabilizing point as fractures multiply and ice speeds up. Scientists warn this pattern could spread to other vulnerable Antarctic ...
New findings show that some coastal regions will become far more acidic than scientists once thought, with upwelling systems pulling deep, CO2-rich waters to the surface and greatly intensifying acidification. Historic coral chemistry and advanced ...
Long-term inhalation of toxic air appears to dull the protective power of regular workouts, according to a massive global study spanning more than a decade and over a million adults. While exercise still helps people live longer, its benefits shrink ...
Human development and climate-driven sea level rise are accelerating global beach erosion and undermining the natural processes that sustain coastal ecosystems. Studies reveal that urban activity on the sand harms biodiversity in every connected ...
Researchers have discovered a low-energy way to recycle Teflon® by using mechanical motion and sodium metal. The process turns the notoriously durable plastic into sodium fluoride that can be reused directly in chemical manufacturing. This creates ...
A photosynthetic bacterium shows a surprising ability to absorb persistent PFAS chemicals, offering a glimpse into biological tools that might one day tackle toxic contamination. Researchers are now exploring genetic and synthetic biology approaches ...

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