Query: In no way, shape, or form are humans warming or cooling the planet.

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 .

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 .

Extinction event <=SEP=> An extinction event ( also known as a mass extinction or biotic crisis ) is a widespread and rapid decrease in the biodiversity on Earth . Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms . It occurs when the rate of extinction increases with respect to the rate of speciation . Because the majority of diversity and biomass on Earth is microbial , and thus difficult to measure , recorded extinction events affect the easily observed , biologically complex component of the biosphere rather than the total diversity and abundance of life .   Extinction occurs at an uneven rate . Based on the fossil record , the background rate of extinctions on Earth is about two to five taxonomic families of marine animals every million years . Marine fossils are mostly used to measure extinction rates because of their superior fossil record and stratigraphic range compared to land animals .   The Great Oxygenation Event was probably the first major extinction event . Since the Cambrian explosion five further major mass extinctions have significantly exceeded the background extinction rate . The most recent and debatably best-known , the Cretaceous -- Paleogene extinction event , which occurred approximately million years ago ( Ma ) , was a large-scale mass extinction of animal and plant species in a geologically short period of time . In addition to the five major mass extinctions , there are numerous minor ones as well , and the ongoing mass extinction caused by human activity is sometimes called the sixth extinction . Mass extinctions seem to be a mainly Phanerozoic phenomenon , with extinction rates low before large complex organisms arose .   Estimates of the number of major mass extinctions in the last 540 million years range from as few as five to more than twenty . These differences stem from the threshold chosen for describing an extinction event as `` major '' , and the data chosen to measure past diversity .

Global cooling <=SEP=> Global cooling was a conjecture during the 1970s of imminent cooling of the Earth 's surface and atmosphere culminating in a period of extensive glaciation . This hypothesis had little support in the scientific community , but gained temporary popular attention due to a combination of a slight downward trend of temperatures from the 1940s to the early 1970s and press reports that did not accurately reflect the full scope of the scientific climate literature , which showed a larger and faster-growing body of literature projecting future warming due to greenhouse gas emissions . The current scientific opinion on climate change is that the Earth has not durably cooled , but underwent global warming throughout the 20th century .

Volcano <=SEP=> A volcano is a rupture in the crust of a planetary-mass object , such as Earth , that allows hot lava , volcanic ash , and gases to escape from a magma chamber below the surface .   Earth 's volcanoes occur because its crust is broken into 17 major , rigid tectonic plates that float on a hotter , softer layer in its mantle . Therefore , on Earth , volcanoes are generally found where tectonic plates are diverging or converging , and most are found underwater . For example , a mid-oceanic ridge , such as the Mid-Atlantic Ridge , has volcanoes caused by divergent tectonic plates pulling apart ; the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates coming together . Volcanoes can also form where there is stretching and thinning of the crust 's , e.g. , in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande Rift in North America . This type of volcanism falls under the umbrella of `` plate hypothesis '' volcanism . Volcanism away from plate boundaries has also been explained as mantle plumes . These so-called `` hotspots '' , for example Hawaii , are postulated to arise from upwelling diapirs with magma from the core -- mantle boundary , 3,000 km deep in the Earth . Volcanoes are usually not created where two tectonic plates slide past one another .   Erupting volcanoes can pose many hazards , not only in the immediate vicinity of the eruption . One such hazard is that volcanic ash can be a threat to aircraft , in particular those with jet engines where ash particles can be melted by the high operating temperature ; the melted particles then adhere to the turbine blades and alter their shape , disrupting the operation of the turbine . Large eruptions can affect temperature as ash and droplets of sulfuric acid obscure the sun and cool the Earth 's lower atmosphere ( or troposphere ) ; however , they also absorb heat radiated up from the Earth , thereby warming the upper atmosphere ( or stratosphere ) . Historically , so-called volcanic winters have caused catastrophic famines .