A comparatively simple molecule, carbon dioxide (CO2) is best known as a major participant to climate change. As a fundamental component of Earth’s atmosphere, its global volume increases are related to the number of machines, animals and humans exhaling.

A touchstone was reached when in April 2014 when CO2 in Earth’s Northern Hemisphere reached continued levels over 400 parts per million (PPM) for the first time. Before the ubiquity of petroleum-burning technologies brought in by the Industrial Revolution (1760 – 1840), estimated levels 240 PPM. If the most disastrous impacts predicted by climate change models are to be avoided, the United Nations’ Intergovernmental Panel on Climate Change declared in May of this year that CO2 must remain lower than 450PPM.

Carbon dioxide basics:

CO2 is the most stable type of carbon known and. as such, is critical to the natural carbon cycle. It is without scent, non-flammable and colorless. As communicated by its name, CO2 consists of one carbon atom and two oxygen atoms. At standardized pressures and temperatures (as published by the National Institute of Standards and Technology), CO2 is in its gas form. Although it is a mere fraction of everything else in the atmosphere, it is nonetheless crucial to virtually all life on Earth. Humans would not have a breathing response without it. Nor fire extinguishers, soda water, decaffeinated coffee or refrigerants.

Unlike in Earth’s atmosphere, carbon dioxide molecules are bountiful in outer space, as the elements is formed supernovae explode in the nurseries of the universe, nebulae. Because it is very cold in outer space, interstellar carbon dioxide is in its solid form. Such “dry ice” exists in immeasurable amounts, floating around the universe. When parts of nebulae are modeled into planets, dry ice becomes trapped and thus a component of the the new planets’ systems.

The history of Venus provides a graphic example of how climate change can occur. That planet’s atmosphere is itself out-of-control greenhouse effect state. Although its further from the Sun, temperatures at the surface are hotter even than on Mercury, the planet closest to the Sun. Carbon dioxide makes up 97 percent of Venus’ atmosphere and is responsible for temperatures there of 900 – 1,110 Fahrenheit. Every planet experiences its own history of climate change episodes and Venus has had its share.

Unlike water (H2O), CO2 does not have a liquid form. Instead, once the temperature at which it is no longer solid (-190.3 degrees Fahrenheit) is exceeded, CO2 changes directly from solid to gas. Because of it lower solid temperature, only half as much CO2 is required when used as a coolant in human technologies. Finally, the amount of CO2 expelled by humans can be surprisingly large. About 0.3 liter leaves the blood stream each minute.

Respiratory systems in living organisms exist to exchange oxygen and carbon dioxide. Through air that is breathed in, carbon dioxide arrives in the mammalian body and, when blood carrying CO2 reaches the lungs, CO2 is discahrged into the lungs and becomes the dominant gas of exhalation. CO2 is basic to life on Earth, is the most important greenhouse gas, as well as the various processes of climate change.