why do we need carbon dioxide in the atmosphere

The Earths early atmosphere is believed to have been mainly carbon dioxide with little or no oxygen gas. The Earths atmosphere today contains around 21 percent oxygen and about 0. 04 percent carbon dioxide. So how did the proportion of carbon dioxide in the atmosphere go down, and the proportion of oxygen go up? photosynthesis The chemical change that occurs in the leaves of green plants. It uses light energy to convert carbon dioxide and water into glucose. Oxygen is produced as a by-product of photosynthesis. This process uses carbon dioxide from the atmosphere (with water and sunlight) to produce oxygen (and glucose). The appearance of plants and algae caused the production of oxygen, which is why the proportion of oxygen went up. Photosynthesis by plants and algae used carbon dioxide from the atmosphere, but this is not the only reason why the proportion of carbon dioxide went down. These processes also absorb carbon dioxide from the atmosphere:
Today, the burning of fossil fuels (coal and oil) is adding carbon dioxide to the atmosphere faster than it can be removed. This means that the level of carbon dioxide in the atmosphere is increasing, contributing to global warming. It also means that the oceans are becoming more acidic as they dissolve increasing amounts of carbon dioxide.


This has an impact on the marine environment, for example making the shells of sea creatures thinner than normal. Now try a. Carbon dioxide is a colorless and non-flammable gas at normal temperature and pressure. Although than nitrogen and oxygen in, carbon dioxide is an important constituent of our planet's air. A molecule of carbon dioxide (CO ) is made up of one carbon atom and two oxygen atoms. Carbon dioxide is an important greenhouse gas that helps to trap heat in our atmosphere. Without it, our planet would be inhospitably cold. However, a gradual increase in CO concentrations in Earth's atmosphere is helping to drive global warming, threatening to disrupt our planet's climate as average global temperatures gradually rise. Carbon dioxide is the fourth most abundant component of dry air. It has a (parts per million by volume) in Earth's atmosphere. Scientists estimate that before human industrial activity, CO concentration was around 270 ppmv. Carbon dioxide levels in our atmosphere have thus risen about 40% since the onset of human industrialization, and are expected to play a troubling role in raising global temperature.


Atmospheric carbon dioxide concentrations have varied substantially in the pre-human history of our planet, and have had profound impacts on global temperatures in the past. Carbon dioxide plays a key role in Earth's, the set of processes that cycle carbon in many forms throughout our environment. Volcanic outgassing and wildfires are two significant natural sources of CO in Earth's atmosphere. Respiration, the process by which organisms liberate energy from food, emits carbon dioxide. When you exhale, it is carbon dioxide (amongst other gases) that you breathe out. Combustion, whether in the guise of wildfires, as a result of slash-and-burn agricultural practices, or in internal combustion engines, produces carbon dioxide. Photosynthesis, the biochemical process by which plants and some microbes create food, uses up carbon dioxide. Photosynthetic organisms combine CO O) to produce carbohydrates (such as sugars) and emit oxygen as a by-product. Places such as forests and areas of the ocean that support photosynthetic microbes therefore act as massive carbon "sinks", removing carbon dioxide from the atmosphere via photosynthesis. Earth's early atmosphere had much higher CO levels and almost no oxygen; the rise of photosynthetic organisms led to an increase in oxygen which enabled the development of oxygen-breathing creatures such as us! , although incomplete combustion due to limited oxygen supply or an excess of carbon can also produce carbon monoxide (CO).


Carbon monoxide, a dangerous pollutant, eventually oxidizes to carbon dioxide. are used to inflate bicycle tires and life jackets and to power paintball guns. The "fizz" in soda pop is supplied by carbon dioxide. Carbon dioxide is also released by yeast during fermentation, giving beer its head and making champagne bubbly. Because it is not flammable, CO is used in some fire extinguishers. Carbon dioxide forms a weak acid, called carbonic acid (H ), when dissolved in water. Carbon dioxide is the most abundant gas in the atmospheres of Mars and Venus. Solid, frozen carbon dioxide is called "dry ice". The polar ice caps of Mars are a mixture of normal water ice and dry ice. Liquid CO only forms at pressures higher than about 5 times the atmospheric pressure on Earth at sea level, so in many situations dry ice does not melt into a liquid form. Instead, it goes directly from a solid state to a gaseous state in a process called sublimation.

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