carbon dioxide

carbon dioxide
Name	Carbon dioxide
Chemical formula	CO2
Molar mass	44.01 g/mol
Appearance	Colorless gas
Density	1.977 g·L−1 (at STP)
Melting point	−56.6 °C (sublimes at 1 atm)
Boiling point	Sublimation at 1 atm
Solubility	1.45 g·L−1 (in water at 20 °C)

carbon dioxide is a linear, triatomic molecule composed of one carbon atom double-bonded to two oxygen atoms; it is a colorless, odorless gas at standard conditions and a major component of Earth's atmosphere. It plays central roles across geosciences, environmental policy, and industrial chemistry, interacting with atmospheric physics, oceanography, and terrestrial ecology. Research on its sources, sinks, and radiative properties informs international negotiations and engineering responses to anthropogenic emissions.

Introduction

Carbon dioxide, as a greenhouse constituent, figures prominently in discussions around the Intergovernmental Panel on Climate Change, United Nations Framework Convention on Climate Change, and national energy strategies such as those of the United States and the European Union. Measurements from observatories like Mauna Loa Observatory and programs run by institutions including the National Oceanic and Atmospheric Administration and the Scripps Institution of Oceanography provide the empirical basis for trend analyses used by agencies such as the National Aeronautics and Space Administration and the World Meteorological Organization. Its study intersects work by scientists associated with awards like the Nobel Prize in Physics and informs major assessments cited by bodies such as the International Energy Agency.

Physical and Chemical Properties

CO2 is a nonpolar linear molecule with sp hybridization around the carbon atom; its spectroscopic signatures are key to remote sensing by satellites such as Orbiting Carbon Observatory missions and instruments developed at organizations like the European Space Agency. At low pressure it sublimes directly from solid to gas, a property exploited in applications and studied in thermodynamics texts used at universities including Massachusetts Institute of Technology and University of Cambridge. Its infrared absorption bands near 4.3 µm and 15 µm contribute to radiative forcing studied by researchers at labs such as the Jet Propulsion Laboratory and published in journals supported by societies like the American Geophysical Union.

Natural Sources and Sinks

Natural sources of CO2 include volcanic emissions observed at locations like Mount Etna and hydrothermal vents studied by expeditions organized by institutions such as the Woods Hole Oceanographic Institution. Respiration by fauna across biomes—from tropical forests in the Amazon Rainforest to peatlands in the Siberian tundra—releases CO2, while photosynthetic uptake by plants in ecosystems monitored by programs like the Long Term Ecological Research Network and carbon sequestration in soils described by researchers at the University of California, Berkeley act as sinks. Oceanic uptake occurs in regions studied during cruises by vessels such as those of the International Ocean Discovery Program and influences carbonate chemistry in basins like the North Atlantic Ocean.

Human Activities and Emissions

Anthropogenic CO2 emissions arise primarily from combustion of fossil fuels in sectors overseen by entities like OPEC, utilities regulated under frameworks in the European Commission, and transport fleets registered in countries including China and the United States. Industrial processes such as cement production at plants highlighted by agencies like the International Energy Agency and land-use changes in regions affected by policies from institutions like the Food and Agriculture Organization alter carbon budgets. Emissions inventories compiled by agencies such as the Environmental Protection Agency and reporting mechanisms under the Paris Agreement inform mitigation strategies developed by governments and nongovernmental organizations like the World Resources Institute.

Role in Climate Change and Atmospheric Science

CO2's radiative forcing is central to projections in assessment reports by the Intergovernmental Panel on Climate Change and to models developed at centers such as the Met Office and NASA Goddard Institute for Space Studies. Paleoclimate archives—ice cores from sites like Vostok Station and EPICA Dome C—provide historical CO2 records that link atmospheric concentrations to events such as the Last Glacial Maximum and abrupt climate shifts. Atmospheric transport and mixing are analyzed using frameworks from research groups at institutions such as the Max Planck Institute for Meteorology and numerical experiments conducted on supercomputers at facilities like the Lawrence Livermore National Laboratory.

Biological Roles and Ecological Impacts

CO2 is the carbon source for photosynthesis carried out by plants studied in departments at Harvard University and by algal communities characterized in work at the Monterey Bay Aquarium Research Institute. Elevated atmospheric concentrations influence plant physiology explored in experiments funded by agencies such as the National Science Foundation and affect community composition in ecosystems managed by organizations like the Nature Conservancy. Ocean acidification driven by dissolved CO2 alters calcifying organisms in regions monitored by the National Oceanic and Atmospheric Administration and has implications for fisheries overseen by bodies such as the Food and Agriculture Organization.

Industrial Uses and Safety Considerations

Industrial uses of CO2 include refrigerant applications in systems developed by companies collaborating with institutes like the Fraunhofer Society, carbonation of beverages marketed by firms in the Beverage Industry, and as a feedstock in processes investigated at chemical plants owned by corporations such as BASF. Carbon capture and storage technologies are piloted in projects supported by consortia including the Global CCS Institute and tested in demonstrations like those at Sleipner Field. Safety considerations—exposure limits set by agencies such as the Occupational Safety and Health Administration and emergency response protocols used by services like Fire and Rescue NSW—address risks of high-concentration exposure and asphyxiation in confined spaces.

Category:Inorganic carbon compounds