query: That humans are causing the rise in atmospheric CO2 is confirmed by multiple isotopic analyses.

positive: Carbon dioxide 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 .

positive: Global warming controversy The global warming controversy concerns the public debate over whether global warming is occurring , how much has occurred in modern times , what has caused it , what its effects will be , whether any action should be taken to curb it , and if so what that action should be . In the scientific literature , there is a strong consensus that global surface temperatures have increased in recent decades and that the trend is caused by human-induced emissions of greenhouse gases . No scientific body of national or international standing disagrees with this view , though a few organizations with members in extractive industries hold non-committal positions . Disputes over the key scientific facts of global warming are more prevalent in the media than in the scientific literature , where such issues are treated as resolved , and such disputes are more prevalent in the United States than globally .   Political and popular debate concerning the existence and cause of climate change includes the reasons for the increase seen in the instrumental temperature record , whether the warming trend exceeds normal climatic variations , and whether human activities have contributed significantly to it . Scientists have resolved these questions decisively in favour of the view that the current warming trend exists and is ongoing , that human activity is the cause , and that it is without precedent in at least 2000 years . Public disputes that also reflect scientific debate include estimates of how responsive the climate system might be to any given level of greenhouse gases ( climate sensitivity ) , how global climate change will play out at local and regional scales , and what the consequences of global warming will be .   Global warming remains an issue of widespread political debate , often split along party political lines , especially in the United States . Many of the issues that are settled within the scientific community , such as human responsibility for global warming , remain the subject of politically or economically motivated attempts to downplay , dismiss or deny them -- an ideological phenomenon categorised by academics and scientists as climate change denial . The sources of funding for those involved with climate science -- both supporting and opposing mainstream scientific positions -- have been questioned by both sides . There are debates about the best policy responses to the science , their cost-effectiveness and their urgency . Climate scientists , especially in the United States , have reported official and oil-industry pressure to censor or suppress their work and hide scientific data , with directives not to discuss the subject in public communications . Legal cases regarding global warming , its effects , and measures to reduce it have reached American courts . The fossil fuels lobby has been identified as overtly or covertly supporting efforts to undermine or discredit the scientific consensus on global warming .

positive: Carbon dioxide in Earth's atmosphere 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 .

positive: Global warming Global warming , also referred to as climate change , is the observed century-scale rise in the average temperature of the Earth 's climate system and its related effects . Multiple lines of scientific evidence show that the climate system is warming . Many of the observed changes since the 1950s are unprecedented in the instrumental temperature record which extends back to the mid 19th century , and in paleoclimate proxy records over thousands of years .   In 2013 , the Intergovernmental Panel on Climate Change ( IPCC ) Fifth Assessment Report concluded that `` It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century . '' The largest human influence has been emission of greenhouse gases such as carbon dioxide , methane and nitrous oxide . Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to for their lowest emissions scenario and 2.6 to for the highest emissions scenario . These findings have been recognized by the national science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing .   Future climate change and associated impacts will differ from region to region around the globe . Anticipated effects include warming global temperature , rising sea levels , changing precipitation , and expansion of deserts in the subtropics . Warming is expected to be greater over land than over the oceans and greatest in the Arctic , with the continuing retreat of glaciers , permafrost and sea ice . Other likely changes include more frequent extreme weather events including heat waves , droughts , heavy rainfall with floods and heavy snowfall ; ocean acidification ; and species extinctions due to shifting temperature regimes . Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels . Because the climate system has a large `` inertia '' and greenhouse gases will stay in the atmosphere for a long time , many of these effects will not only exist for decades or centuries , but will persist for tens of thousands of years .   Possible societal responses to global warming include mitigation by emissions reduction , adaptation to its effects , building systems resilient to its effects , and possible future climate engineering . Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) ,  whose ultimate objective is to prevent dangerous anthropogenic climate change . Parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2.0 C-change relative to pre-industrial levels , with efforts made to limit warming to 1.5 C-change .   Public reactions to global warming and concern about its effects are also increasing . A global 2015 Pew Research Center report showed a median of 54 % consider it `` a very serious problem '' . There are significant regional differences , with Americans and Chinese ( whose economies are responsible for the greatest annual CO2 emissions ) among the least concerned .

negative: Suess effect The Suess effect is a change in the ratio of the atmospheric concentrations of heavy isotopes of carbon ( 13C and 14C ) by the admixture of large amounts of fossil-fuel derived CO2 , which is depleted in 13CO2 and contains no 14CO2 . It is named for the Austrian chemist Hans Suess , who noted the influence of this effect on the accuracy of radiocarbon dating . More recently , the Suess effect has been used in studies of climate change . The term originally referred only to dilution of atmospheric 14CO2 . The concept was later extended to dilution of 13CO2 and to other reservoirs of carbon such as the oceans and soils .

negative: Soil respiration Soil respiration refers to the production of carbon dioxide when soil organisms respire . This includes respiration of plant roots , the rhizosphere , microbes and fauna .   Soil respiration is a key ecosystem process that releases carbon from the soil in the form of CO2 . CO2 is acquired from the atmosphere and converted into organic compounds in the process of photosynthesis . Plants use these organic compounds to build structural components or respire them to release energy . When plant respiration occurs below-ground in the roots , it adds to soil respiration . Over time , plant structural components are consumed by heterotrophs . This heterotrophic consumption releases CO2 and when this CO2 is released by below-ground organisms , it is considered soil respiration .   The amount of soil respiration that occurs in an ecosystem is controlled by several factors . The temperature , moisture , nutrient content and level of oxygen in the soil can produce extremely disparate rates of respiration . These rates of respiration can be measured in a variety of methods . Other methods can be used to separate the source components , in this case the type of photosynthetic pathway ( C3/C4 ) , of the respired plant structures .   Soil respiration rates can be largely affected by human activity . This is because humans have the ability to and have been changing the various controlling factors of soil respiration for numerous years . Global climate change is composed of numerous changing factors including rising atmospheric CO2 , increasing temperature and shifting precipitation patterns . All of these factors can affect the rate of global soil respiration . Increased nitrogen fertilization by humans also has the potential to effect rates over the entire Earth .   Soil respiration and its rate across ecosystems is extremely important to understand . This is because soil respiration plays a large role in global carbon cycling as well as other nutrient cycles . The respiration of plant structures releases not only CO2 but also other nutrients in those structures , such as nitrogen . Soil respiration is also associated with positive feedbacks with global climate change . Positive feedbacks are when a change in a system produces response in the same direction of the change . Therefore , soil respiration rates can be effected by climate change and then respond by enhancing climate change .

negative: Clumped isotopes Clumped isotopes are heavy isotopes that are bonded to other heavy isotopes . The carbonate clumped-isotope thermometer , or `` 13C -- 18O order/disorder carbonate thermometer '' , is a new approach for paleoclimate reconstruction , basing on the temperature dependence of the clumping of 13C and 18O into bonds within the carbonate mineral lattice . This approach has the advantage that the 18O ratio in water is not necessary ( different from the δ18O approach ) , but for precise paleotemperature estimation , it also needs very large and uncontaminated samples , long analytical runs , and extensive replication . Commonly used sample sources for paleoclimatological work include corals , otoliths , bivalves , and foraminifera . Results are usually expressed as Δ47 ( said as `` cap 47 '' ) , which is the deviation of the ratio of isotopologues of CO2 with a molecular weight of 47 to those with a weight of 44 from the ratio expected if they were randomly distributed .

negative: Isotope fractionation Isotope fractionation describes processes that affect the relative abundance of isotopes , often used in isotope geochemistry . Normally , the focus is on stable isotopes of the same element . Isotopic fractionation in the natural environment can be measured by isotope analysis , using isotope-ratio mass spectrometry , to separate different element isotopes on the basis of their mass-to-charge ratio , an important tool to understand natural systems . For example , in biochemistry processes cause a fluctuation in the amount of isotopes of carbon ratios incorporated into a biological being . The difference between the true amount of carbon and the amount in the plant is known as isotope fractionation .

negative: Estuarine acidification Estuarine acidification is a decrease in the pH of coastal marine ecosystems , specifically those of estuaries . pH change in estuaries is more complicated than in the open ocean due to direct impacts from land run-off and coastal current dynamics . Ocean acidification is the ongoing decrease in the pH of the Earth 's oceans , caused by the absorption of carbon dioxide ( CO2 ) from the atmosphere ( 0.1 units over the last century ) . The ocean absorbs 30-40 % of all CO2 emitted to the atmosphere ; this increase in aqueous carbon dioxide causes a decline in the pH of the ocean surface . As carbon dioxide combines with water , it releases protons ( hydrogen ions ) , based on the following equation :   CO2 + H2O ↔ H2CO3 ↔ HCO3 + H + ↔ CO3 + 2 H +

negative: Kinetic fractionation Kinetic fractionation is an isotopic fractionation process that separates stable isotopes from each other by their mass during unidirectional processes . Biological processes are generally unidirectional and are very good examples of `` kinetic '' isotope reactions . All organisms preferentially use lighter isotopic species , because `` energy costs '' are lower , resulting in a significant fractionation between the substrate ( heavier ) and the biologically mediated product ( lighter ) . As an example , photosynthesis preferentially takes up the light isotope of carbon 12C during assimilation of an atmospheric CO2 molecule . This kinetic isotope fractionation explains why plant material ( and thus fossil fuels , which are derived from plants ) is typically depleted in 13C by 25 per mil ( 2.5 per cent ) relative to most inorganic carbon on Earth .   A naturally occurring example of non-biological kinetic fractionation occurs during the evaporation of seawater to form clouds under conditions in which some part of the transport is unidirectional , such as evaporation into very dry air . In this instance , isotopically lighter water molecules ( i.e. , those with 16O ) will evaporate slightly more easily than will the isotopically heavier water molecules with 18O , and this difference will be greater than it would be if the evaporation was taking place under equilibrium conditions ( with bidirectional transport ) .   During this process the oxygen isotopes are fractionated : the clouds become enriched with 16O , and the seawater becomes enriched in 18O . Whereas equilibrium fractionation makes the vapor about 10 per mil ( 1 % ) depleted in 18O relative to the liquid water , kinetic fractionation enhances this fractionation and often makes vapor that is about 15 per mil ( 1.5 % ) depleted . Condensation occurs almost exclusively by equilibrium processes , and so it enriches cloud droplets somewhat less than evaporation depletes the vapor . This explains part of the reason why rainwater is observed to be isotopically lighter than seawater .   The isotope of hydrogen in water , deuterium , is much less sensitive to kinetic fractionation than oxygen isotopes , relative to the very large equilibrium fractionation of deuterium . For this reason kinetic fractionation does not deplete deuterium nearly as much , in a relative sense , as 18O . This gives rise to an excess of deuterium in vapor and rainfall , relative to seawater . The value of this `` deuterium excess '' , as it is called , is about +10 per mil ( 1 % ) in most meteoric waters and its non-zero value is a direct manifestation of kinetic isotope fractionation .   A generalized treatment of kinetic isotopic effects is via the GEBIK and GEBIF equations describing transient kinetic isotope effects .

negative: The Greening of Planet Earth The Greening of Planet Earth is a half-hour-long video produced by the coal industry , which argues that rising CO2 levels will be beneficial to agriculture , and that policies intending to reduce CO2 levels are therefore misguided . The video argues that rising CO2 levels both directly stimulate plant growth and , as a result of their warming properties , cause winter temperatures to rise , thereby indirectly stimulating plant growth . It was produced in 1991 and released the following year . A sequel , entitled , The Greening of Planet Earth Continues , was released in 1998 . The video was narrated by Sherwood Idso . After the video was made , it was distributed to thousands of journalists by a coal industry group . The video became very popular viewing in the George H. W. Bush White House and elsewhere in Washington , where it was promoted before the 1992 Earth Summit , and , according to some reports , became especially popular with then-chief of staff John H. Sununu .

negative: Katsuko Saruhashi was a geochemist who made some of the first measurements of carbon dioxide ( CO2 ) levels in seawater and subsequently showed the evidence in seawater and the atmosphere of the dangers of radioactive fallout .

negative: FUTBOLIN FUTBOLIN ( FUll Transfer By Optimized LINe-by-line methods ) : Multi-level multiple scattering radiative transfer model for the calculation of line-by-line atmospheric emission/transmission spectra in planetary atmospheres . It has been developed by Javier Martin-Torres ( AS&M . Inc , NASA/Langley Research Center , Hampton , VA , USA ; Jet Propulsion Laboratory , Pasadena , CA ; Now at IACT ( CSIC-URG ) , Granada , SPAIN ) . It allows generating high-resolution synthetic spectra in the 0.3-1000 micrometre spectral range .   The code can handle spherical or plane-parallel atmospheres . It reads spectral lines in HITRAN or GEISA format and can handle CO2 line mixing and continuum absorption from H2O , O2 , N2 and CO2 . It also takes into account the Non Local Thermodynamic Equilibrium ( NLTE ) effects on the rotational , electronic and vibrational populations of the atmospheric species and allows to specify any combinations of clouds , coverage and spectral albedo . It has been used to model the Earth 's atmosphere , and the atmospheres of Mars , Venus , and Titan .   The code can calculate reflection , transmission , absorption , infrared cooling rate , and flux spectra .

negative: CO2 fertilization effect The fertilization effect or carbon fertilization effect suggests that the increase of carbon dioxide in the atmosphere increases the rate of photosynthesis in plants . The effect varies by species and availability of water .   From a quarter to half of Earth 's vegetated lands has shown significant greening over the last 35 years largely due to rising levels of atmospheric carbon dioxide .   One related trend may be what has been termed `` Arctic greening . '' Scientists have been finding , of late , that as northern portions of the planet warm up even as total atmospheric carbon dioxide increases , there 's been an increase in plant growth in these regions .   Studies led by Trevor Keenan from the Department of Energy 's Lawrence Berkeley National Laboratory ( Berkeley Lab ) show that , from 2002 to 2014 , plants appear to have gone into overdrive , starting to pull more carbon dioxide out of the air than they have done before . The result was that the rate at which carbon dioxide accumulates in the atmosphere did not increase during this time period , although previously , it had grown considerably in concert with growing greenhouse gas emissions .

negative: Isotopes of aluminium Aluminium ( 13Al ) has 22 known isotopes from 21Al to 42Al and 4 known isomers . Only 27Al ( stable isotope ) and 26Al ( radioactive isotope , t1/2 = 7.2 × 105 y ) occur naturally , however 27Al has a natural abundance of 99.9 + % . Other than 26Al , all radioisotopes have half-lives under 7 minutes , most under a second . The standard atomic weight is . 26Al is produced from argon in the atmosphere by spallation caused by cosmic-ray protons . Aluminium isotopes have found practical application in dating marine sediments , manganese nodules , glacial ice , quartz in rock exposures , and meteorites . The ratio of 26Al to 10Be has been used to study the role of sediment transport , deposition , and storage , as well as burial times , and erosion , on 105 to 106 year time scales .   Cosmogenic aluminium-26 was first applied in studies of the Moon and meteorites . Meteorite fragments , after departure from their parent bodies , are exposed to intense cosmic-ray bombardment during their travel through space , causing substantial 26Al production . After falling to Earth , atmospheric shielding protects the meteorite fragments from further 26Al production , and its decay can then be used to determine the meteorite 's terrestrial age . Meteorite research has also shown that 26Al was relatively abundant at the time of formation of our planetary system . Most meteoriticists believe that the energy released by the decay of 26Al was responsible for the melting and differentiation of some asteroids after their formation 4.55 billion years ago .

negative: Cap carbonate Cap carbonates are layers of distinctively textured carbonate rocks which typically form the uppermost layer of sedimentary sequences reflecting major glaciations in the geological record .   The rising temperatures , and increased oceanic surface area - due to reduced ice cover and rising sea levels - at the end of a glaciation increase the rate of precipitation .   High concentrations of greenhouse gases such as carbon dioxide ( CO2 ) must build up in the atmosphere to overcome the effect of the high reflectivity ( albedo ) of ice and allow temperatures to rise sufficiently to begin melting .   Increased precipitation dissolves carbon dioxide from the atmosphere , falling as a weak carbonic acid - acid rain .   This would weather exposed silicate and carbonate rock , including readily-attacked glacial debris , which would release large amounts of calcium . When washed into the ocean , these precipitate to form distinctively textured layers of carbonate sedimentary rock .   A heavily debated cap carbonate appears at the top of the Gaskiers glaciation , believed by many to be global in extent .

negative: Mazuku In geology , a mazuku ( Swahili : evil wind ) is a pocket of carbon dioxide-rich air that can be lethal to any human or animal life inside . Mazuku are created when carbon dioxide accumulates in pockets low to the ground . CO2 is heavier than air , which causes it to stay close to the ground , and is also undetectable by human olfactory or visual senses in most conditions .   Mazuku can be related to volcanic activity or to a natural disaster known as a limnic eruption . In the first case , noxious gases are released from the Earth 's crust into the atmosphere , whereas in the second case the gases originate deep in a lake and boil rapidly to the surface . Because of their nature as sporadic and subtle events , few mazuku have been recorded , but there is a growing understanding of them based on historical and fossil evidence .

negative: Lime kiln A lime kiln is a kiln used for the calcination of limestone ( calcium carbonate ) to produce the form of lime called quicklime ( calcium oxide ) . The chemical equation for this reaction is   CaCO3 + heat → CaO + CO2   This reaction takes place at 900 ° C ( 1650 ° F ; at which temperature the partial pressure of CO2 is 1 atmosphere ) , but a temperature around 1000 ° C ( 1800 ° F ; at which temperature the partial pressure of CO2 is 3.8 atmospheres ) is usually used to make the reaction proceed quickly . Excessive temperature is avoided because it produces unreactive , `` dead-burned '' lime .   Slaked lime ( calcium hydroxide ) can be formed by mixing water with quicklime .

negative: Recycled fuel Fuel made of residues as CO2 produced by using a primary fuel .   For example , CO2 pollution in the atmosphere , produced by petrol burning or other sources , can be extracted to produce fuel through an artificial photosynthesis based in nanotechnology , which helps to mitigate pollution , climate change and energy issues .

negative: Ifood (isotopic food) iFood ( isotopic food ) contains nutritients in which some atoms are replaced with their heavier non-radioactive isotopes ( such as 13C and 2H , derived from C4-plants ) . Biomolecules that incorporate heavier isotopes give rise to more stable molecular structures with increased resistance to damages associated with ageing . The inclusion of heavy isotopes might be either active ( selection for heavier isotopes ) or passive ( incorporation reflecting the existing abundance ) . Consumption of foods relatively rich in heavy isotopes , especially at the early stages of the organism 's development , is linked , so far hypothetically , with enhanced longevity . Consumed with food , some biomolecules ( e.g. , essential amino acids ) become building material for the human cells . Molecules that contain heavier isotopes are less prone to destructive effect of free radicals ( which is the key point of the free-radical theory of ageing ) .   After publication in scientific literature , the concept of isotopic food moved on to popular science publications and even became a hot topic in mass media where the anti-ageing properties were often mistakenly attributed to heavy water .

negative: Art Spivack Arthur J. Spivack ( July 9 , 1956 - Queens , New York ) , or Art , is an American geochemist . He is currently a professor at the University of Rhode Island Graduate School of Oceanography .   Spivack 's research interest is the geochemistry of the oceans , atmosphere , and crust . He developed the use of boron isotopes for determining the pH of ancient oceans . This approach provides a principal basis for estimating atmospheric CO2 concentrations of the last several tens of million years . He led the investigation of the 2015 Salty Brine Beach explosion . He has also contributed to scientific understanding of geochemical fluxes in mid-ocean-ridge hydrothermal systems and subduction zones and understanding of subseafloor life .   Spivack received his bachelor 's degree ( 1980 ) in chemistry from the Massachusetts Institute of Technology ( MIT ) and his Ph.D. in Oceanography from MIT and Woods Hole Oceanographic Institution ( 1986 ) .

negative: On Your Knees Cave On Your Knees Cave ( 49-PET-408 ) is an archaeological site located in southeastern Alaska ( Prince of Wales Island ) . Human remains were found at the site in 1996 that dated between 9,730 ± 60 and 9,880 ± 50 radiocarbon YBP ( Years Before Present ) or a calendrical date of 10,300 YBP . In addition to human skeletal remains , stone tools and animal bones were discovered . DNA analyses performed on the human skeletal remains document the presence of mitochondrial haplogroup D which occurs widely in the Americas . Isotopic analysis indicated that the individual had a primarily marine based diet .

negative: Steptoean positive carbon isotope excursion The Steptoean Positive Carbon Isotope Excursion ( SPICE ) was a geological event which occurred about 500 million years ago at the end of the Cambrian Period . The SPICE event was a sudden reversal of the anoxia ( lack of oxygen ) that had steadily spread throughout the oceans during the Cambrian which also affected the atmosphere . After the SPICE event , oxygen levels recovered and levels in the atmosphere may have risen as high as 30 % , higher than the 21 % of the atmosphere that prevails today . The sudden increase in oxygen led to an explosion of life across the globe .

negative: Carbon rift Carbon rift is a theory attributing the input and output of carbon into the environment to human capitalistic systems . This is a derivative of Karl Marx 's concept of metabolic rift . In practical terms , increased commodity production demands that greater levels of carbon dioxide ( or CO2 ) be emitted into the biosphere via fossil fuel consumption . Carbon rift theory states that this ultimately disrupts the natural carbon cycle and that this `` rift '' has adverse effects on nearly every aspect of life . Many of the specifics regarding how this metabolic carbon rift interacts with capitalism are proposed by Brett Clark and Richard York in a 2005 article titled `` Carbon Metabolism : Global capitalism , climate change , and the biospheric rift '' in the journal Theory and Society . Researchers such as Jean P. Sapinski of the University of Oregon claim that , despite increased interest in closing the carbon rift , it is projected that as long as capitalism continues , there is little hope of reducing the rift .   Both deforestation and the emission of greenhouse gases have been linked to increased atmospheric CO2 levels . Carbon rift theory states that these are the result of human production through capitalistic systems . There are proposed solutions to climate change such as geoengineering proposed in the December 2015 Paris Agreement . However , some argue that the capitalist mode of production is at fault for the emission of greenhouse gas and that solutions must be found to this issue before climate change itself can be addressed .   Carbon rift theory , while rarely criticized directly , often indirectly receives criticism regarding the underlying causes of climate change and attributing the stated effects to alternative explanations for climate change , instead of as a result of human activity . Such explanations include the Chaotic Solar System Theory and that increased water vapor is responsible for climate change .

negative: Dole effect The Dole effect , named after Malcolm Dole , describes an inequality in the ratio of the heavy isotope 18O ( a `` standard '' oxygen atom with two additional neutrons ) to the lighter 16O , measured in the atmosphere and seawater . This ratio is usually denoted δ18O .   It was noticed in 1935 that air contained more 18O than seawater ; this was quantified in 1975 to 23.5 ‰ , but later refined as 23.88 ‰ in 2005 . The imbalance arises mainly as a result of respiration in plants and in animals . Due to thermodynamics of isotope reactions , respiration removes the lighter -- hence more reactive -- 16O in preference to 18O , increasing the relative amount of 18O in the atmosphere .   The inequality is balanced by photosynthesis . Photosynthesis emits oxygen with the same isotopic composition ( i.e. the ratio between 18O and 16O ) as the water ( H2O ) used in the reaction , which is independent of the atmospheric ratio . Thus when atmospheric 18O levels are high enough , photosynthesis will act as a reducing factor . However , as a complicating factor , the degree of fractionation ( i.e. change in isotope ratio ) occurring due to photosynthesis is not entirely dependent on the water drawn up by the plant , as fractionation can occur as a result of preferential evaporation of and other small but significant processes .

negative: TEA laser A TEA laser is a gas laser energized by a high voltage electrical discharge in a gas mixture generally at or above atmospheric pressure . The most common types are CO2 lasers and Excimer lasers , both used extensively in industry and research . The acronym `` TEA '' stands for Transversely Excited Atmospheric .

negative: Atmosphere of Titan The atmosphere of Titan is the layer of gases surrounding Titan , the largest moon of Saturn . It is the only thick atmosphere of a natural satellite in the Solar System .   The presence of a significant atmosphere was first suspected by Spanish astronomer Josep Comas i Solà , who observed distinct limb darkening on Titan in 1903 , and confirmed by Gerard P. Kuiper in 1944 using a spectroscopic technique that yielded an estimate of an atmospheric partial pressure of methane of the order of 100 millibars ( 10 kPa ) . Subsequent observations in the 1970s showed that Kuiper 's figures had been significant underestimates ; methane abundances in Titan 's atmosphere were ten times higher , and the surface pressure was at least double what he had predicted . The high surface pressure meant that methane could only form a small fraction of Titan 's atmosphere . In 1980 , Voyager 1 made the first detailed observations of Titan 's atmosphere , revealing that its surface pressure was higher than Earth 's , at 1.5 bars . On June 23 , 2014 , a NASA/ESA said its isotopic abundances were evidence that the nitrogen in the atmosphere of Titan came from materials in the Oort cloud , associated with comets , and not from the materials that formed Saturn in earlier times .

negative: Giovanni (meteorology) Giovanni ( meteorology ) - Web interface that allows users to analyze NASA 's gridded data from various satellite and surface observations .   Giovanni provides researchers with the capability to examine data on atmospheric chemistry , atmospheric temperature , water vapor and clouds , atmospheric aerosols , precipitation , and ocean chlorophyll and surface temperature . The primary data consist of global gridded data sets with reduced spatial resolution . Basic analytical functions performed by Giovanni currently are carried out by the Grid Analysis and Display System ( GrADS ) .   The GES-DISC Interactive Online Visualization ANd aNalysis Infrastructure ( Giovanni ) allows to explore satellite data using sophisticated analyses and visualizations .  Giovanni allows access to data from multiple remote sites , supports multiple data formats including Hierarchical Data Format ( HDF ) , HDF-EOS , network Common Data Form ( netCDF ) , GRIdded Binary ( GRIB ) , and binary , and multiple plot types including area , time , Hovmoller , and image animation .

negative: Mesopause The mesopause is the temperature minimum at the boundary between the mesosphere and the thermosphere atmospheric regions . Due to the lack of solar heating and very strong radiative cooling from carbon dioxide , the mesosphere is the coldest region on Earth with temperatures as low as -100 ° C ( -148 ° F or 173 K ) . The altitude of the mesopause for many years was assumed to be at around 85 km ( 53 mi . ) , but observations to higher altitudes and modeling studies in the last 10 years have shown that in fact the mesopause consists of two minima - one at about 85 km and a stronger minimum at about 100 km . ( 62 mi . )   Another feature is that the summer mesopause is cooler than the winter ( sometimes referred to as the mesopause anomaly ) . It is due to a summer-to-winter circulation giving rise to upwelling at the summer pole and downwelling at the winter pole . Air rising will expand and cool resulting in a cold summer mesopause and conversely downwelling air results in compression and associated increase in temperature at the winter mesopause . In the mesosphere the summer-to-winter circulation is due to gravity wave dissipation , which deposits momentum against the mean east-west flow , resulting in a small north-south circulation .   In recent years the mesopause has also been the focus of studies on global climate change associated with increases in CO2 . Unlike the troposphere , where greenhouse gases result in the atmosphere heating up , increased CO2 in the mesosphere acts to cool the atmosphere due to increased radiative emission . This results in a measurable effect - the mesopause should become cooler with increased CO2 . Observations do show a decrease of temperature of the mesopause , though the magnitude of this decrease varies and is subject to further study . Modeling studies of this phenomenon have also been carried out .

negative: David Archer (scientist) David Archer is a computational ocean chemist , and has been a professor at the Geophysical Sciences department at the University of Chicago since 1993 . He has published research on the carbon cycle of the ocean and the sea floor . He has worked on the history of atmospheric CO2 concentration , the expectation of fossil fuel CO2 over geologic time scales in the future , and the impact of CO2 on future ice age cycles , ocean methane hydrate decomposition , and coral reefs .   He is a contributor to the RealClimate blog .

negative: Greenhouse effect The greenhouse effect is the process by which radiation from a planet 's atmosphere warms the planet 's surface to a temperature above what it would be without its atmosphere .   If a planet 's atmosphere contains radiatively active gases ( i.e. , greenhouse gases ) the atmosphere will radiate energy in all directions . Part of this radiation is directed towards the surface , warming it . The downward component of this radiation -- that is , the strength of the greenhouse effect -- will depend on the atmosphere 's temperature and on the amount of greenhouse gases that the atmosphere contains .   On Earth , the atmosphere is warmed by absorption of infrared thermal radiation from the underlying surface ( heated by the sun ) , absorption of shorter wavelength radiant energy from the sun , and convective heat fluxes from the surface . Greenhouse gases in the atmosphere radiate energy , some of which is directed to the surface and lower atmosphere . The mechanism that produces this difference between the actual surface temperature and the effective temperature is due to the atmosphere and is known as the greenhouse effect .   Earth 's natural greenhouse effect is critical to supporting life . Human activities , primarily the burning of fossil fuels and clearing of forests , have intensified the natural greenhouse effect , causing global warming .   The mechanism is named after a faulty analogy with the effect of solar radiation passing through glass and warming a greenhouse . The way a greenhouse retains heat is fundamentally different , as a greenhouse works by reducing airflow and retaining warm air inside the structure .

negative: Meteoritics Meteoritics is a science that deals with meteoritesA meteorite is a solid rock which has landed on Earth after originating in space . It should not be confused with a meteor ( a shooting star , caused by an incoming object burning up in the Earth 's atmosphere ) or a meteoroid ( a small body orbiting within the Solar System ) . and other extraterrestrial materials that further our understanding of the origin and history of the Solar System . It is closely connected to cosmochemistry , mineralogy and geochemistry . A specialist who studies meteoritics is known as a meteoriticist .   Scientific research in meteoritics includes the collection , identification and classification of meteorites , and the analysis of samples taken from them in a laboratory . Typical analyses include investigation of the minerals that make up the meteorite , their relative locations , orientations and chemical compositions , analysis of isotope ratios and radiometric dating . These techniques are used to determine the age , formation process and subsequent history of the material forming the meteorite . This provides information on the history of the Solar System , how it formed and evolved , and the process of planet formation .

negative: Proxy (climate) In the study of past climates ( `` paleoclimatology '' ) , climate proxies are preserved physical characteristics of the past that stand in for direct meteorological measurements and enable scientists to reconstruct the climatic conditions over a longer fraction of the Earth 's history . Reliable global records of climate only began in the 1880s , and proxies provide the only means for scientists to determine climatic patterns before record-keeping began .   Examples of proxies include ice cores , tree rings , sub-fossil pollen , boreholes , corals , lake and ocean sediments , and carbonate speleothems . The character of deposition or rate of growth of the proxies ' material has been influenced by the climatic conditions of the time in which they were laid down or grew . Chemical traces produced by climatic changes , such as quantities of particular isotopes , can be recovered from proxies . Some proxies , such as gas bubbles trapped in ice , enable traces of the ancient atmosphere to be recovered and measured directly to provide a history of fluctuations in the composition of the Earth 's atmosphere . To produce the most precise results , systematic cross-verification between proxy indicators is necessary for accuracy in readings and record-keeping .   Proxies can be combined to produce temperature reconstructions longer than the instrumental temperature record and can inform discussions of global warming . The distribution of proxy records , just like the instrumental record , is not at all uniform , with more records in the northern hemisphere .

negative: Anthropogenic cloud An anthropogenic or artificial cloud , is a cloud induced by human activity . Although generally clouds covering the sky have only a natural origin , from the beginning of the Industrial Revolution , the use of fossil fuels and water vapor and other gases emitted by nuclear , thermal and geothermal power plants yield significant alterations of the local weather conditions . These new atmospheric conditions can thus enhance cloud formation . Homogenitus is the term used to designate the origin of clouds produced by human activities .   Various methods have been proposed for creating and utilizing this weather phenomenon . Experiments have also been carried out for various studies . For example , Russian scientists have been studying artificial clouds for more than 50 years . But by far the greatest number of anthropogenic clouds are airplane contrails ( condensation trails ) and rocket trails .

negative: NYC: Tornado Terror NYC : Tornado Terror is a 2008 Canadian made for TV disaster film . It stars Nicole de Boer , Sebastian Spence , and Jerry Wasserman . It premiered on Syfy on October 4 , 2008 , and is directed by Tibor Takács .   The film is about global warming which causes the upper and lower atmosphere to separate so that their different movements generate huge electrical charges which causes huge electrical tornadoes to drop on New York City causing destruction and loss of life . Dr. Cassie Lawrence tries to stop the twisters as chaos ensues . NASA ignores the mayor who recommends following Dr. Lawrence 's advice and use silver iodide on the atmosphere instead , which makes things worse , so it is down to our heroes to use a rebel scientist with his own makeshift rockets to use dry ice ( frozen CO2 ) . The problem is solved , but before the film ends , the same storm effects begin in Paris .

negative: Isotopes of sulfur Sulfur ( 16S ) has 24 known isotopes with mass numbers ranging from 26 to 49 , four of which are stable : 32S ( 95.02 % ) , 33S ( 0.75 % ) , 34S ( 4.21 % ) , and 36S ( 0.02 % ) . The preponderance of sulfur-32 is explained by its production from carbon-12 plus successive fusion capture of five helium nuclei , in the so-called alpha process of exploding type II supernovae ( see silicon burning ) .   Other than 35S , the radioactive isotopes of sulfur are all comparatively short-lived . 35S is formed from cosmic ray spallation of 40Ar in the atmosphere . It has a half-life of 87 days . The next longest-lived radioisotope is sulfur-38 , with a half-life of 17 minutes . The shortest-lived is 49S , with a half-life shorter than 200 nanoseconds .   When sulfide minerals are precipitated , isotopic equilibration among solids and liquid may cause small differences in the δS-64 values of co-genetic minerals . The differences between minerals can be used to estimate the temperature of equilibration . The δC-13 and δS-34 of coexisting carbonates and sulfides can be used to determine the pH and oxygen fugacity of the ore-bearing fluid during ore formation .   In most forest ecosystems , sulfate is derived mostly from the atmosphere ; weathering of ore minerals and evaporites also contribute some sulfur . Sulfur with a distinctive isotopic composition has been used to identify pollution sources , and enriched sulfur has been added as a tracer in hydrologic studies . Differences in the natural abundances can also be used in systems where there is sufficient variation in the 34S of ecosystem components . Rocky Mountain lakes thought to be dominated by atmospheric sources of sulfate have been found to have different δS-34 values from oceans believed to be dominated by watershed sources of sulfate .