Query: Without carbon dioxide, all life on Earth would die

Relevant passages:
Earth <=SEP=> Earth ( from Eorðe -LSB- Γαῖα , Gaia -RSB- Terra ) , otherwise known as the World or the Globe , is the third planet from the Sun and the only object in the Universe known to harbor life . It is the densest planet in the Solar System and the largest of the four terrestrial planets .   According to radiometric dating and other sources of evidence , Earth formed about 4.54 billion years ago . Earth 's gravity interacts with other objects in space , especially the Sun and the Moon , Earth 's only natural satellite . During one orbit around the Sun , Earth rotates about its axis over 365 times ; thus , an Earth year is about 365.26 days long . Earth 's axis of rotation is tilted , producing seasonal variations on the planet 's surface . The gravitational interaction between the Earth and Moon causes ocean tides , stabilizes the Earth 's orientation on its axis , and gradually slows its rotation .   Earth 's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years . About 71 % of Earth 's surface is covered with water , mostly by its oceans . The remaining 29 % is land consisting of continents and islands that together have many lakes , rivers and other sources of water that contribute to the hydrosphere . The majority of Earth 's polar regions are covered in ice , including the Antarctic ice sheet and the sea ice of the Arctic ice pack . Earth 's interior remains active with a solid iron inner core , a liquid outer core that generates the Earth 's magnetic field , and a convecting mantle that drives plate tectonics .   Within the first billion years of Earth 's history , life appeared in the oceans and began to affect the Earth 's atmosphere and surface , leading to the proliferation of aerobic and anaerobic organisms . Some geological evidence indicates that life may have arisen as much as 4.1 billion years ago . Since then , the combination of Earth 's distance from the Sun , physical properties , and geological history have allowed life to evolve and thrive . In the history of the Earth , biodiversity has gone through long periods of expansion , occasionally punctuated by mass extinction events . Over 99 % of all species that ever lived on Earth are extinct . Estimates of the number of species on Earth today vary widely ; most species have not been described . Over 7.4 billion humans live on Earth and depend on its biosphere and minerals for their survival . Humans have developed diverse societies and cultures ; politically , the world has about 200 sovereign states .

Future of Earth <=SEP=> The biological and geological future of Earth can be extrapolated based upon the estimated effects of several long-term influences . These include the chemistry at Earth 's surface , the rate of cooling of the planet 's interior , the gravitational interactions with other objects in the Solar System , and a steady increase in the Sun 's luminosity . An uncertain factor in this extrapolation is the ongoing influence of technology introduced by humans , such as climate engineering , which could cause significant changes to the planet . The current Holocene extinction is being caused by technology and the effects may last for up to five million years . In turn , technology may result in the extinction of humanity , leaving the planet to gradually return to a slower evolutionary pace resulting solely from long-term natural processes .   Over time intervals of hundreds of millions of years , random celestial events pose a global risk to the biosphere , which can result in mass extinctions . These include impacts by comets or asteroids with diameters of 5 -- or more , and the possibility of a massive stellar explosion , called a supernova , within a 100-light-year radius of the Sun , called a Near-Earth supernova . Other large-scale geological events are more predictable . If the long-term effects of global warming are disregarded , Milankovitch theory predicts that the planet will continue to undergo glacial periods at least until the Quaternary glaciation comes to an end . These periods are caused by variations in eccentricity , axial tilt , and precession of the Earth 's orbit . As part of the ongoing supercontinent cycle , plate tectonics will probably result in a supercontinent in 250 -- 350 million years . Some time in the next 1.5 -- 4.5 billion years , the axial tilt of the Earth may begin to undergo chaotic variations , with changes in the axial tilt of up to 90 ° .   During the next four billion years , the luminosity of the Sun will steadily increase , resulting in a rise in the solar radiation reaching the Earth . This will result in a higher rate of weathering of silicate minerals , which will cause a decrease in the level of carbon dioxide in the atmosphere . In about 600 million years from now , the level of CO2 will fall below the level needed to sustain C3 carbon fixation photosynthesis used by trees . Some plants use the C4 carbon fixation method , allowing them to persist at concentrations as low as 10 parts per million . However , the long-term trend is for plant life to die off altogether . The extinction of plants will be the demise of almost all animal life , since plants are the base of the food chain on Earth .   In about one billion years , the solar luminosity will be 10 % higher than at present . This will cause the atmosphere to become a `` moist greenhouse '' , resulting in a runaway evaporation of the oceans . As a likely consequence , plate tectonics will come to an end , and with them the entire carbon cycle . Following this event , in about 2 − 3 billion years , the planet 's magnetic dynamo may cease , causing the magnetosphere to decay and leading to an accelerated loss of volatiles from the outer atmosphere . Four billion years from now , the increase in the Earth 's surface temperature will cause a runaway greenhouse effect , heating the surface enough to melt it . By that point , all life on the Earth will be extinct . The most probable fate of the planet is absorption by the Sun in about 7.5 billion years , after the star has entered the red giant phase and expanded to cross the planet 's current orbit .

Carbon dioxide <=SEP=> Carbon dioxide ( chemical formula ) is a colorless gas with a density about 60 % higher than that of air ( 1.225 g/L ) that is odorless at normally encountered concentrations . Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms . It occurs naturally in Earth 's atmosphere as a trace gas at a concentration of about 0.04 percent ( 400 ppm ) by volume . Natural sources include volcanoes , hot springs and geysers , and it is freed from carbonate rocks by dissolution in water and acids . Because carbon dioxide is soluble in water , it occurs naturally in groundwater , rivers and lakes , ice caps , glaciers and seawater . It is present in deposits of petroleum and natural gas .   As the source of available carbon in the carbon cycle , atmospheric carbon dioxide is the primary carbon source for life on Earth and its concentration in Earth 's pre-industrial atmosphere since late in the Precambrian has been regulated by photosynthetic organisms and geological phenomena . Plants , algae and cyanobacteria use light energy to photosynthesize carbohydrate from carbon dioxide and water , with oxygen produced as a waste product .   Carbon dioxide is produced by all aerobic organisms when they metabolize carbohydrates and lipids to produce energy by respiration . It is returned to water via the gills of fish and to the air via the lungs of air-breathing land animals , including humans . Carbon dioxide is produced during the processes of decay of organic materials and the fermentation of sugars in bread , beer and winemaking . It is produced by combustion of wood and other organic materials and fossil fuels such as coal , peat , petroleum and natural gas .   It is a versatile industrial material , used , for example , as an inert gas in welding and fire extinguishers , as a pressurizing gas in air guns and oil recovery , as a chemical feedstock and in liquid form as a solvent in decaffeination of coffee and supercritical drying . It is added to drinking water and carbonated beverages including beer and sparkling wine to add effervescence . The frozen solid form of , known as `` dry ice '' is used as a refrigerant and as an abrasive in dry-ice blasting .   Carbon dioxide is the most significant long-lived greenhouse gas in Earth 's atmosphere . Since the Industrial Revolution anthropogenic emissions - primarily from use of fossil fuels and deforestation - have rapidly increased its concentration in the atmosphere , leading to global warming . Carbon dioxide also causes ocean acidification because it dissolves in water to form carbonic acid .

Carbon dioxide in Earth's atmosphere <=SEP=> Carbon dioxide is an important trace gas in Earth 's atmosphere . Currently it constitutes about 0.041 % ( equal to 410 parts per million ; ppm ) by volume of the atmosphere . Despite its relatively small concentration is a potent greenhouse gas and plays a vital role in regulating Earth 's surface temperature through radiative forcing and the greenhouse effect . Reconstructions show that concentrations of in the atmosphere have varied , ranging from as high as 7,000 ppm during the Cambrian period about 500 million years ago to as low as 180 ppm during the Quaternary glaciation of the last two million years .   Carbon dioxide is an integral part of the carbon cycle , a biogeochemical cycle in which carbon is exchanged between the Earth 's oceans , soil , rocks and the biosphere . Plants and other photoautotrophs use solar energy to produce carbohydrate from atmospheric carbon dioxide and water by photosynthesis . Almost all other organisms depend on carbohydrate derived from photosynthesis as their primary source of energy and carbon compounds .   The current episode of global warming is attributed to increasing emissions of and other greenhouse gases into Earth 's atmosphere . The global annual mean concentration of in the atmosphere has increased by more than 40 % since the start of the Industrial Revolution , from 280 ppm , the level it had for the last 10,000 years leading up to the mid-18th century , to 399 ppm as of 2015 . The present concentration is the highest in at least the past 800,000 years and likely the highest in the past 20 million years . The increase has been caused by anthropogenic sources , particularly the burning of fossil fuels and deforestation . The daily average concentration of atmospheric CO2 at Mauna Loa Observatory first exceeded 400 ppm on 10 May 2013 . It is currently rising at a rate of approximately 2 ppm/year and accelerating . An estimated 30 -- 40 % of the released by humans into the atmosphere dissolves into oceans , rivers and lakes , which contributes to ocean acidification .