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110-517: Version 2 of the AQE is a single unit, Wi-Fi connected device which can be configured using a cell phone. It has two variants; indoor and outdoor. The device can be fitted with sensors for CO 2 , NO 2 , SO 2 , ozone , carbon monoxide , volatile organic compounds and particulates (PM10, PM2.5 and PM1.0). The particulate sensors can detect particles as small as 0.3 μm (microns), using two Plantower PMS5003 laser sensors. The PM2.5 measurements of

220-562: A broader sense also includes previous long-term changes to Earth's climate. The current rise in global temperatures is driven by human activities , especially fossil fuel burning since the Industrial Revolution . Fossil fuel use, deforestation , and some agricultural and industrial practices release greenhouse gases . These gases absorb some of the heat that the Earth radiates after it warms from sunlight , warming

330-590: A decadal timescale. Other changes are caused by an imbalance of energy from external forcings . Examples of these include changes in the concentrations of greenhouse gases , solar luminosity , volcanic eruptions, and variations in the Earth's orbit around the Sun. To determine the human contribution to climate change, unique "fingerprints" for all potential causes are developed and compared with both observed patterns and known internal climate variability . For example, solar forcing—whose fingerprint involves warming

440-516: A decline in basic activity level and information usage at 1000 ppm, when compared to 500 ppm. However a review of the literature found that a reliable subset of studies on the phenomenon of carbon dioxide induced cognitive impairment to only show a small effect on high-level decision making (for concentrations below 5000 ppm). Most of the studies were confounded by inadequate study designs, environmental comfort, uncertainties in exposure doses and differing cognitive assessments used. Similarly

550-446: A fixed structure. However, in a Coulomb explosion imaging experiment, an instantaneous image of the molecular structure can be deduced. Such an experiment has been performed for carbon dioxide. The result of this experiment, and the conclusion of theoretical calculations based on an ab initio potential energy surface of the molecule, is that none of the molecules in the gas phase are ever exactly linear. This counter-intuitive result

660-611: A glass state similar to other members of its elemental family, like silicon dioxide (silica glass) and germanium dioxide . Unlike silica and germania glasses, however, carbonia glass is not stable at normal pressures and reverts to gas when pressure is released. At temperatures and pressures above the critical point, carbon dioxide behaves as a supercritical fluid known as supercritical carbon dioxide . Table of thermal and physical properties of saturated liquid carbon dioxide: Table of thermal and physical properties of carbon dioxide (CO 2 ) at atmospheric pressure: Carbon dioxide

770-542: A lot of light to being dark after the ice has melted, they start absorbing more heat . Local black carbon deposits on snow and ice also contribute to Arctic warming. Arctic surface temperatures are increasing between three and four times faster than in the rest of the world. Melting of ice sheets near the poles weakens both the Atlantic and the Antarctic limb of thermohaline circulation , which further changes

880-412: A marked increase in temperature. Ongoing changes in climate have had no precedent for several thousand years. Multiple independent datasets all show worldwide increases in surface temperature, at a rate of around 0.2 °C per decade. The 2014–2023 decade warmed to an average 1.19 °C [1.06–1.30 °C] compared to the pre-industrial baseline (1850–1900). Not every single year was warmer than

990-491: A mature forest will produce as much CO 2 from respiration and decomposition of dead specimens (e.g., fallen branches) as is used in photosynthesis in growing plants. Contrary to the long-standing view that they are carbon neutral, mature forests can continue to accumulate carbon and remain valuable carbon sinks , helping to maintain the carbon balance of Earth's atmosphere. Additionally, and crucially to life on earth, photosynthesis by phytoplankton consumes dissolved CO 2 in

1100-428: A much larger denominator and a much smaller value than the true K a1 . The bicarbonate ion is an amphoteric species that can act as an acid or as a base, depending on pH of the solution. At high pH, it dissociates significantly into the carbonate ion ( CO 2− 3 ): In organisms, carbonic acid production is catalysed by the enzyme known as carbonic anhydrase . In addition to altering its acidity,

1210-408: A physical climate model. These models simulate how population, economic growth , and energy use affect—and interact with—the physical climate. With this information, these models can produce scenarios of future greenhouse gas emissions. This is then used as input for physical climate models and carbon cycle models to predict how atmospheric concentrations of greenhouse gases might change. Depending on

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1320-461: A result of climate change. Global sea level is rising as a consequence of thermal expansion and the melting of glaciers and ice sheets . Sea level rise has increased over time, reaching 4.8 cm per decade between 2014 and 2023. Over the 21st century, the IPCC projects 32–62 cm of sea level rise under a low emission scenario, 44–76 cm under an intermediate one and 65–101 cm under

1430-474: A result. The World Health Organization calls climate change one of the biggest threats to global health in the 21st century. Societies and ecosystems will experience more severe risks without action to limit warming . Adapting to climate change through efforts like flood control measures or drought-resistant crops partially reduces climate change risks, although some limits to adaptation have already been reached. Poorer communities are responsible for

1540-417: A small share of global emissions , yet have the least ability to adapt and are most vulnerable to climate change . Many climate change impacts have been observed in the first decades of the 21st century, with 2023 the warmest on record at +1.48 °C (2.66 °F) since regular tracking began in 1850. Additional warming will increase these impacts and can trigger tipping points , such as melting all of

1650-416: A study on the effects of the concentration of CO 2 in motorcycle helmets has been criticized for having dubious methodology in not noting the self-reports of motorcycle riders and taking measurements using mannequins. Further when normal motorcycle conditions were achieved (such as highway or city speeds) or the visor was raised the concentration of CO 2 declined to safe levels (0.2%). Poor ventilation

1760-467: A typical single C–O bond, and shorter than most other C–O multiply bonded functional groups such as carbonyls . Since it is centrosymmetric, the molecule has no electric dipole moment . As a linear triatomic molecule, CO 2 has four vibrational modes as shown in the diagram. In the symmetric and the antisymmetric stretching modes, the atoms move along the axis of the molecule. There are two bending modes, which are degenerate , meaning that they have

1870-548: A very high emission scenario. Marine ice sheet instability processes in Antarctica may add substantially to these values, including the possibility of a 2-meter sea level rise by 2100 under high emissions. Climate change has led to decades of shrinking and thinning of the Arctic sea ice . While ice-free summers are expected to be rare at 1.5 °C degrees of warming, they are set to occur once every three to ten years at

1980-519: A warming level of 2 °C. Higher atmospheric CO 2 concentrations cause more CO 2 to dissolve in the oceans, which is making them more acidic . Because oxygen is less soluble in warmer water, its concentrations in the ocean are decreasing , and dead zones are expanding. Greater degrees of global warming increase the risk of passing through ' tipping points '—thresholds beyond which certain major impacts can no longer be avoided even if temperatures return to their previous state. For instance,

2090-485: A waste product. In turn, oxygen is consumed and CO 2 is released as waste by all aerobic organisms when they metabolize organic compounds to produce energy by respiration . CO 2 is released from organic materials when they decay or combust, such as in forest fires. When carbon dioxide dissolves in water, it forms carbonate and mainly bicarbonate ( HCO − 3 ), which causes ocean acidification as atmospheric CO 2 levels increase. Carbon dioxide

2200-469: Is Emiliania huxleyi whose calcite scales have formed the basis of many sedimentary rocks such as limestone , where what was previously atmospheric carbon can remain fixed for geological timescales. Plants can grow as much as 50% faster in concentrations of 1,000 ppm CO 2 when compared with ambient conditions, though this assumes no change in climate and no limitation on other nutrients. Elevated CO 2 levels cause increased growth reflected in

2310-419: Is 304.128(15) K (30.978(15) °C) at 7.3773(30) MPa (72.808(30) atm). Another form of solid carbon dioxide observed at high pressure is an amorphous glass-like solid. This form of glass, called carbonia , is produced by supercooling heated CO 2 at extreme pressures (40–48  GPa , or about 400,000 atmospheres) in a diamond anvil . This discovery confirmed the theory that carbon dioxide could exist in

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2420-569: Is 53% more dense than dry air, but is long lived and thoroughly mixes in the atmosphere. About half of excess CO 2 emissions to the atmosphere are absorbed by land and ocean carbon sinks . These sinks can become saturated and are volatile, as decay and wildfires result in the CO 2 being released back into the atmosphere. CO 2 is eventually sequestered (stored for the long term) in rocks and organic deposits like coal , petroleum and natural gas . Nearly all CO2 produced by humans goes into

2530-399: Is China's iKair (pronounced "I Care"), but it has a closed, proprietary platform rather than the AQE's open source hardware and open data design. In 2014, IBM announced a partnership with the government of China for analytics software to process data from pollution sensors. Official website [REDACTED] Carbon dioxide Carbon dioxide is a chemical compound with

2640-415: Is an end product of cellular respiration in organisms that obtain energy by breaking down sugars, fats and amino acids with oxygen as part of their metabolism . This includes all plants, algae and animals and aerobic fungi and bacteria. In vertebrates , the carbon dioxide travels in the blood from the body's tissues to the skin (e.g., amphibians ) or the gills (e.g., fish ), from where it dissolves in

2750-564: Is an estimated total sea level rise of 2.3 metres per degree Celsius (4.2 ft/°F) after 2000 years. Oceanic CO 2 uptake is slow enough that ocean acidification will also continue for hundreds to thousands of years. Deep oceans (below 2,000 metres (6,600 ft)) are also already committed to losing over 10% of their dissolved oxygen by the warming which occurred to date. Further, the West Antarctic ice sheet appears committed to practically irreversible melting, which would increase

2860-402: Is commercially used in its solid form, commonly known as " dry ice ". The solid-to-gas phase transition occurs at 194.7 Kelvin and is called sublimation . The symmetry of a carbon dioxide molecule is linear and centrosymmetric at its equilibrium geometry. The length of the carbon–oxygen bond in carbon dioxide is 116.3  pm , noticeably shorter than the roughly 140 pm length of

2970-429: Is connected to the user's Ethernet LAN connection. A second unit monitors NO 2 and CO levels and reports these readings every few minutes to the base unit via a custom wireless protocol. The base unit reports these readings to Xively and the AQE website. Add-ons are available for purchase on the website, that add PM2.5 dust , Ozone , and VOC sensors. Despite being labelled a not-consumer-ready "hobbyist" device by

3080-711: Is determined by modelling the carbon cycle and climate sensitivity to greenhouse gases. According to UNEP , global warming can be kept below 1.5 °C with a 50% chance if emissions after 2023 do not exceed 200 gigatonnes of CO 2 . This corresponds to around 4 years of current emissions. To stay under 2.0 °C, the carbon budget is 900 gigatonnes of CO 2 , or 16 years of current emissions. The climate system experiences various cycles on its own which can last for years, decades or even centuries. For example, El Niño events cause short-term spikes in surface temperature while La Niña events cause short term cooling. Their relative frequency can affect global temperature trends on

3190-399: Is independent of where greenhouse gases are emitted, because the gases persist long enough to diffuse across the planet. Since the pre-industrial period, the average surface temperature over land regions has increased almost twice as fast as the global average surface temperature. This is because oceans lose more heat by evaporation and oceans can store a lot of heat . The thermal energy in

3300-632: Is one of the main causes of excessive CO 2 concentrations in closed spaces, leading to poor indoor air quality . Carbon dioxide differential above outdoor concentrations at steady state conditions (when the occupancy and ventilation system operation are sufficiently long that CO 2 concentration has stabilized) are sometimes used to estimate ventilation rates per person. Higher CO 2 concentrations are associated with occupant health, comfort and performance degradation. ASHRAE Standard 62.1–2007 ventilation rates may result in indoor concentrations up to 2,100 ppm above ambient outdoor conditions. Thus if

3410-410: Is ordinarily a difficult and slow reaction: The redox potential for this reaction near pH 7 is about −0.53 V versus the standard hydrogen electrode . The nickel-containing enzyme carbon monoxide dehydrogenase catalyses this process. Photoautotrophs (i.e. plants and cyanobacteria ) use the energy contained in sunlight to photosynthesize simple sugars from CO 2 absorbed from

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3520-450: Is primarily attributed to sulfate aerosols produced by the combustion of fossil fuels with heavy sulfur concentrations like coal and bunker fuel . Smaller contributions come from black carbon (from combustion of fossil fuels and biomass), and from dust. Globally, aerosols have been declining since 1990 due to pollution controls, meaning that they no longer mask greenhouse gas warming as much. Aerosols also have indirect effects on

3630-405: Is produced as a by-product. Ribulose-1,5-bisphosphate carboxylase oxygenase , commonly abbreviated to RuBisCO, is the enzyme involved in the first major step of carbon fixation, the production of two molecules of 3-phosphoglycerate from CO 2 and ribulose bisphosphate , as shown in the diagram at left. RuBisCO is thought to be the single most abundant protein on Earth. Phototrophs use

3740-444: Is radiating into space. Warming reduces average snow cover and forces the retreat of glaciers . At the same time, warming also causes greater evaporation from the oceans , leading to more atmospheric humidity , more and heavier precipitation . Plants are flowering earlier in spring, and thousands of animal species have been permanently moving to cooler areas. Different regions of the world warm at different rates . The pattern

3850-516: Is shaped by feedbacks, which either amplify or dampen the change. Self-reinforcing or positive feedbacks increase the response, while balancing or negative feedbacks reduce it. The main reinforcing feedbacks are the water-vapour feedback , the ice–albedo feedback , and the net effect of clouds. The primary balancing mechanism is radiative cooling , as Earth's surface gives off more heat to space in response to rising temperature. In addition to temperature feedbacks, there are feedbacks in

3960-472: Is the true first acid dissociation constant, defined as where the denominator includes only covalently bound H 2 CO 3 and does not include hydrated CO 2 (aq). The much smaller and often-quoted value near 4.16 × 10 (or pK a1 = 6.38) is an apparent value calculated on the (incorrect) assumption that all dissolved CO 2 is present as carbonic acid, so that Since most of the dissolved CO 2 remains as CO 2 molecules, K a1 (apparent) has

4070-503: Is the main cause of these increased CO 2 concentrations, which are the primary cause of climate change . Its concentration in Earth's pre-industrial atmosphere since late in the Precambrian was regulated by organisms and geological features. Plants , algae and cyanobacteria use energy from sunlight to synthesize carbohydrates from carbon dioxide and water in a process called photosynthesis , which produces oxygen as

4180-407: Is the major reason why different climate models project different magnitudes of warming for a given amount of emissions. A climate model is a representation of the physical, chemical and biological processes that affect the climate system. Models include natural processes like changes in the Earth's orbit, historical changes in the Sun's activity, and volcanic forcing. Models are used to estimate

4290-420: Is transparent to visible light but absorbs infrared radiation , acting as a greenhouse gas . Carbon dioxide is soluble in water and is found in groundwater , lakes , ice caps , and seawater . It is a trace gas in Earth's atmosphere at 421  parts per million (ppm) , or about 0.042% (as of May 2022) having risen from pre-industrial levels of 280 ppm or about 0.028%. Burning fossil fuels

4400-419: Is trivially due to the fact that the nuclear motion volume element vanishes for linear geometries. This is so for all molecules except diatomic molecules . Carbon dioxide is soluble in water, in which it reversibly forms H 2 CO 3 (carbonic acid), which is a weak acid , because its ionization in water is incomplete. The hydration equilibrium constant of carbonic acid is, at 25 °C: Hence,

4510-417: Is unclear. A related phenomenon driven by climate change is woody plant encroachment , affecting up to 500 million hectares globally. Climate change has contributed to the expansion of drier climate zones, such as the expansion of deserts in the subtropics . The size and speed of global warming is making abrupt changes in ecosystems more likely. Overall, it is expected that climate change will result in

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4620-465: Is used in CO 2 scrubbers and has been suggested as a possible starting point for carbon capture and storage by amine gas treating . Only very strong nucleophiles, like the carbanions provided by Grignard reagents and organolithium compounds react with CO 2 to give carboxylates : In metal carbon dioxide complexes , CO 2 serves as a ligand , which can facilitate the conversion of CO 2 to other chemicals. The reduction of CO 2 to CO

4730-511: The Atlantic meridional overturning circulation (AMOC), and irreversible damage to key ecosystems like the Amazon rainforest and coral reefs can unfold in a matter of decades. The long-term effects of climate change on oceans include further ice melt, ocean warming , sea level rise, ocean acidification and ocean deoxygenation. The timescale of long-term impacts are centuries to millennia due to CO 2 's long atmospheric lifetime. The result

4840-661: The Earth's energy budget . Sulfate aerosols act as cloud condensation nuclei and lead to clouds that have more and smaller cloud droplets. These clouds reflect solar radiation more efficiently than clouds with fewer and larger droplets. They also reduce the growth of raindrops , which makes clouds more reflective to incoming sunlight. Indirect effects of aerosols are the largest uncertainty in radiative forcing . While aerosols typically limit global warming by reflecting sunlight, black carbon in soot that falls on snow or ice can contribute to global warming. Not only does this increase

4950-573: The Greenland ice sheet is already melting, but if global warming reaches levels between 1.7 °C and 2.3 °C, its melting will continue until it fully disappears. If the warming is later reduced to 1.5 °C or less, it will still lose a lot more ice than if the warming was never allowed to reach the threshold in the first place. While the ice sheets would melt over millennia, other tipping points would occur faster and give societies less time to respond. The collapse of major ocean currents like

5060-840: The Greenland ice sheet . Under the 2015 Paris Agreement , nations collectively agreed to keep warming "well under 2 °C". However, with pledges made under the Agreement, global warming would still reach about 2.8 °C (5.0 °F) by the end of the century. Limiting warming to 1.5 °C would require halving emissions by 2030 and achieving net-zero emissions by 2050. Fossil fuel use can be phased out by conserving energy and switching to energy sources that do not produce significant carbon pollution. These energy sources include wind , solar , hydro , and nuclear power . Cleanly generated electricity can replace fossil fuels for powering transportation , heating buildings , and running industrial processes. Carbon can also be removed from

5170-635: The Industrial Revolution , naturally-occurring amounts of greenhouse gases caused the air near the surface to be about 33 °C warmer than it would have been in their absence. Human activity since the Industrial Revolution, mainly extracting and burning fossil fuels ( coal , oil , and natural gas ), has increased the amount of greenhouse gases in the atmosphere. In 2022, the concentrations of CO 2 and methane had increased by about 50% and 164%, respectively, since 1750. These CO 2 levels are higher than they have been at any time during

5280-518: The World Economic Forum , 14.5 million more deaths are expected due to climate change by 2050. 30% of the global population currently live in areas where extreme heat and humidity are already associated with excess deaths. By 2100, 50% to 75% of the global population would live in such areas. While total crop yields have been increasing in the past 50 years due to agricultural improvements, climate change has already decreased

5390-414: The carbon cycle . While plants on land and in the ocean absorb most excess emissions of CO 2 every year, that CO 2 is returned to the atmosphere when biological matter is digested, burns, or decays. Land-surface carbon sink processes, such as carbon fixation in the soil and photosynthesis, remove about 29% of annual global CO 2 emissions. The ocean has absorbed 20 to 30% of emitted CO 2 over

5500-400: The chemical formula CO 2 . It is made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature and at normally-encountered concentrations it is odorless. As the source of carbon in the carbon cycle , atmospheric CO 2 is the primary carbon source for life on Earth. In the air, carbon dioxide

5610-402: The climate system . Solar irradiance has been measured directly by satellites , and indirect measurements are available from the early 1600s onwards. Since 1880, there has been no upward trend in the amount of the Sun's energy reaching the Earth, in contrast to the warming of the lower atmosphere (the troposphere ). The upper atmosphere (the stratosphere ) would also be warming if the Sun

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5720-971: The extinction of many species. The oceans have heated more slowly than the land, but plants and animals in the ocean have migrated towards the colder poles faster than species on land. Just as on land, heat waves in the ocean occur more frequently due to climate change, harming a wide range of organisms such as corals, kelp , and seabirds . Ocean acidification makes it harder for marine calcifying organisms such as mussels , barnacles and corals to produce shells and skeletons ; and heatwaves have bleached coral reefs . Harmful algal blooms enhanced by climate change and eutrophication lower oxygen levels, disrupt food webs and cause great loss of marine life. Coastal ecosystems are under particular stress. Almost half of global wetlands have disappeared due to climate change and other human impacts. Plants have come under increased stress from damage by insects. The effects of climate change are impacting humans everywhere in

5830-432: The socioeconomic scenario and the mitigation scenario, models produce atmospheric CO 2 concentrations that range widely between 380 and 1400 ppm. The environmental effects of climate change are broad and far-reaching, affecting oceans , ice, and weather. Changes may occur gradually or rapidly. Evidence for these effects comes from studying climate change in the past, from modelling, and from modern observations. Since

5940-405: The 18th century and 1970 there was little net warming, as the warming impact of greenhouse gas emissions was offset by cooling from sulfur dioxide emissions. Sulfur dioxide causes acid rain , but it also produces sulfate aerosols in the atmosphere, which reflect sunlight and cause global dimming . After 1970, the increasing accumulation of greenhouse gases and controls on sulfur pollution led to

6050-612: The 1950s, droughts and heat waves have appeared simultaneously with increasing frequency. Extremely wet or dry events within the monsoon period have increased in India and East Asia. Monsoonal precipitation over the Northern Hemisphere has increased since 1980. The rainfall rate and intensity of hurricanes and typhoons is likely increasing , and the geographic range likely expanding poleward in response to climate warming. Frequency of tropical cyclones has not increased as

6160-500: The 1980s, the terms global warming and climate change became more common, often being used interchangeably. Scientifically, global warming refers only to increased surface warming, while climate change describes both global warming and its effects on Earth's climate system , such as precipitation changes. Climate change can also be used more broadly to include changes to the climate that have happened throughout Earth's history. Global warming —used as early as 1975 —became

6270-574: The AQE version 2 had an R correlation factor of 0.79 to 0.85 with a professional reference sensor, in a field test run by the South Coast Air Quality Management District . (An R of 1 indicates perfect correlation, whereas 0 indicates a complete lack of correlation). The AQE grew out of Internet of Things meetup groups in New York City and Amsterdam , led by Pachube evangelist Ed Borden. The concept

6380-440: The Arctic is forcing many species to relocate or become extinct . Even if efforts to minimize future warming are successful, some effects will continue for centuries. These include ocean heating , ocean acidification and sea level rise . Climate change threatens people with increased flooding , extreme heat, increased food and water scarcity, more disease, and economic loss . Human migration and conflict can also be

6490-435: The Arctic is another major feedback, this reduces the reflectivity of the Earth's surface in the region and accelerates Arctic warming . This additional warming also contributes to permafrost thawing, which releases methane and CO 2 into the atmosphere. Around half of human-caused CO 2 emissions have been absorbed by land plants and by the oceans. This fraction is not static and if future CO 2 emissions decrease,

6600-497: The CO 2 released by the chemical reactions for making cement , steel , aluminum , and fertilizer . Methane emissions come from livestock , manure, rice cultivation , landfills, wastewater, and coal mining , as well as oil and gas extraction . Nitrous oxide emissions largely come from the microbial decomposition of fertilizer . While methane only lasts in the atmosphere for an average of 12 years, CO 2 lasts much longer. The Earth's surface absorbs CO 2 as part of

6710-604: The Earth will be able to absorb up to around 70%. If they increase substantially, it'll still absorb more carbon than now, but the overall fraction will decrease to below 40%. This is because climate change increases droughts and heat waves that eventually inhibit plant growth on land, and soils will release more carbon from dead plants when they are warmer . The rate at which oceans absorb atmospheric carbon will be lowered as they become more acidic and experience changes in thermohaline circulation and phytoplankton distribution. Uncertainty over feedbacks, particularly cloud cover,

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6820-441: The absorption of sunlight, it also increases melting and sea-level rise. Limiting new black carbon deposits in the Arctic could reduce global warming by 0.2 °C by 2050. The effect of decreasing sulfur content of fuel oil for ships since 2020 is estimated to cause an additional 0.05 °C increase in global mean temperature by 2050. As the Sun is the Earth's primary energy source, changes in incoming sunlight directly affect

6930-439: The air and water: Carbon dioxide is colorless. At low concentrations, the gas is odorless; however, at sufficiently high concentrations, it has a sharp, acidic odor. At standard temperature and pressure , the density of carbon dioxide is around 1.98 kg/m , about 1.53 times that of air . Carbon dioxide has no liquid state at pressures below 0.51795(10) MPa (5.11177(99) atm ). At a pressure of 1 atm (0.101325 MPa),

7040-411: The atmosphere , for instance by increasing forest cover and farming with methods that capture carbon in soil . Before the 1980s it was unclear whether the warming effect of increased greenhouse gases was stronger than the cooling effect of airborne particulates in air pollution . Scientists used the term inadvertent climate modification to refer to human impacts on the climate at this time. In

7150-452: The atmosphere. volcanic CO 2 emissions are more persistent, but they are equivalent to less than 1% of current human-caused CO 2 emissions. Volcanic activity still represents the single largest natural impact (forcing) on temperature in the industrial era. Yet, like the other natural forcings, it has had negligible impacts on global temperature trends since the Industrial Revolution. The climate system's response to an initial forcing

7260-430: The atmosphere. Less than 1% of CO2 produced annually is put to commercial use, mostly in the fertilizer industry and in the oil and gas industry for enhanced oil recovery . Other commercial applications include food and beverage production, metal fabrication, cooling, fire suppression and stimulating plant growth in greenhouses. Carbon dioxide cannot be liquefied at atmospheric pressure. Low-temperature carbon dioxide

7370-454: The biggest threats to global health in the 21st century. Scientists have warned about the irreversible harms it poses. Extreme weather events affect public health, and food and water security . Temperature extremes lead to increased illness and death. Climate change increases the intensity and frequency of extreme weather events. It can affect transmission of infectious diseases , such as dengue fever and malaria . According to

7480-540: The carbon cycle, such as the fertilizing effect of CO 2 on plant growth. Feedbacks are expected to trend in a positive direction as greenhouse gas emissions continue, raising climate sensitivity. These feedback processes alter the pace of global warming. For instance, warmer air can hold more moisture in the form of water vapour , which is itself a potent greenhouse gas. Warmer air can also make clouds higher and thinner, and therefore more insulating, increasing climate warming. The reduction of snow cover and sea ice in

7590-551: The climate cycled through ice ages . One of the hotter periods was the Last Interglacial , around 125,000 years ago, where temperatures were between 0.5 °C and 1.5 °C warmer than before the start of global warming. This period saw sea levels 5 to 10 metres higher than today. The most recent glacial maximum 20,000 years ago was some 5–7 °C colder. This period has sea levels that were over 125 metres (410 ft) lower than today. Temperatures stabilized in

7700-869: The condition. There are few studies of the health effects of long-term continuous CO 2 exposure on humans and animals at levels below 1%. Occupational CO 2 exposure limits have been set in the United States at 0.5% (5000 ppm) for an eight-hour period. At this CO 2 concentration, International Space Station crew experienced headaches, lethargy, mental slowness, emotional irritation, and sleep disruption. Studies in animals at 0.5% CO 2 have demonstrated kidney calcification and bone loss after eight weeks of exposure. A study of humans exposed in 2.5 hour sessions demonstrated significant negative effects on cognitive abilities at concentrations as low as 0.1% (1000   ppm) CO 2 likely due to CO 2 induced increases in cerebral blood flow. Another study observed

7810-684: The current interglacial period beginning 11,700 years ago . This period also saw the start of agriculture. Historical patterns of warming and cooling, like the Medieval Warm Period and the Little Ice Age , did not occur at the same time across different regions. Temperatures may have reached as high as those of the late 20th century in a limited set of regions. Climate information for that period comes from climate proxies , such as trees and ice cores . Around 1850 thermometer records began to provide global coverage. Between

7920-517: The degenerate pair of bending modes at 667 cm (wavelength 15.0 μm). The symmetric stretching mode does not create an electric dipole so is not observed in IR spectroscopy, but it is detected in Raman spectroscopy at 1388 cm (wavelength 7.20 μm), with a Fermi resonance doublet at 1285 cm . In the gas phase, carbon dioxide molecules undergo significant vibrational motions and do not keep

8030-403: The degree of warming future emissions will cause when accounting for the strength of climate feedbacks . Models also predict the circulation of the oceans, the annual cycle of the seasons, and the flows of carbon between the land surface and the atmosphere. The physical realism of models is tested by examining their ability to simulate current or past climates. Past models have underestimated

8140-427: The destroyed trees release CO 2 , and are not replaced by new trees, removing that carbon sink . Between 2001 and 2018, 27% of deforestation was from permanent clearing to enable agricultural expansion for crops and livestock. Another 24% has been lost to temporary clearing under the shifting cultivation agricultural systems. 26% was due to logging for wood and derived products, and wildfires have accounted for

8250-566: The dispersing effects of wind, it can collect in sheltered/pocketed locations below average ground level, causing animals located therein to be suffocated. Carrion feeders attracted to the carcasses are then also killed. Children have been killed in the same way near the city of Goma by CO 2 emissions from the nearby volcano Mount Nyiragongo . The Swahili term for this phenomenon is mazuku . Adaptation to increased concentrations of CO 2 occurs in humans, including modified breathing and kidney bicarbonate production, in order to balance

8360-401: The distribution of heat and precipitation around the globe. The World Meteorological Organization estimates there is an 80% chance that global temperatures will exceed 1.5 °C warming for at least one year between 2024 and 2028. The chance of the 5-year average being above 1.5 °C is almost half. The IPCC expects the 20-year average global temperature to exceed +1.5 °C in

8470-444: The dominant direct influence on temperature from land use change. Thus, land use change to date is estimated to have a slight cooling effect. Air pollution, in the form of aerosols, affects the climate on a large scale. Aerosols scatter and absorb solar radiation. From 1961 to 1990, a gradual reduction in the amount of sunlight reaching the Earth's surface was observed. This phenomenon is popularly known as global dimming , and

8580-610: The early 2030s. The IPCC Sixth Assessment Report (2021) included projections that by 2100 global warming is very likely to reach 1.0–1.8 °C under a scenario with very low emissions of greenhouse gases , 2.1–3.5 °C under an intermediate emissions scenario , or 3.3–5.7 °C under a very high emissions scenario . The warming will continue past 2100 in the intermediate and high emission scenarios, with future projections of global surface temperatures by year 2300 being similar to millions of years ago. The remaining carbon budget for staying beneath certain temperature increases

8690-541: The effects of blood acidification ( acidosis ). Several studies suggested that 2.0 percent inspired concentrations could be used for closed air spaces (e.g. a submarine ) since the adaptation is physiological and reversible, as deterioration in performance or in normal physical activity does not happen at this level of exposure for five days. Yet, other studies show a decrease in cognitive function even at much lower levels. Also, with ongoing respiratory acidosis , adaptation or compensatory mechanisms will be unable to reverse

8800-551: The electrical conductivity of fully deionized water without CO 2 saturation is comparably low in relation to these data. CO 2 is a potent electrophile having an electrophilic reactivity that is comparable to benzaldehyde or strongly electrophilic α,β-unsaturated carbonyl compounds . However, unlike electrophiles of similar reactivity, the reactions of nucleophiles with CO 2 are thermodynamically less favored and are often found to be highly reversible. The reversible reaction of carbon dioxide with amines to make carbamates

8910-430: The entire atmosphere—is ruled out because only the lower atmosphere has warmed. Atmospheric aerosols produce a smaller, cooling effect. Other drivers, such as changes in albedo , are less impactful. Greenhouse gases are transparent to sunlight , and thus allow it to pass through the atmosphere to heat the Earth's surface. The Earth radiates it as heat , and greenhouse gases absorb a portion of it. This absorption slows

9020-469: The gas deposits directly to a solid at temperatures below 194.6855(30) K (−78.4645(30) °C) and the solid sublimes directly to a gas above this temperature. In its solid state, carbon dioxide is commonly called dry ice . Liquid carbon dioxide forms only at pressures above 0.51795(10) MPa (5.11177(99) atm); the triple point of carbon dioxide is 216.592(3) K (−56.558(3) °C) at 0.51795(10) MPa (5.11177(99) atm) (see phase diagram). The critical point

9130-604: The global climate system has grown with only brief pauses since at least 1970, and over 90% of this extra energy has been stored in the ocean . The rest has heated the atmosphere , melted ice, and warmed the continents. The Northern Hemisphere and the North Pole have warmed much faster than the South Pole and Southern Hemisphere . The Northern Hemisphere not only has much more land, but also more seasonal snow cover and sea ice . As these surfaces flip from reflecting

9240-601: The harvestable yield of crops, with wheat, rice and soybean all showing increases in yield of 12–14% under elevated CO 2 in FACE experiments. Increased atmospheric CO 2 concentrations result in fewer stomata developing on plants which leads to reduced water usage and increased water-use efficiency . Studies using FACE have shown that CO 2 enrichment leads to decreased concentrations of micronutrients in crop plants. This may have knock-on effects on other parts of ecosystems as herbivores will need to eat more food to gain

9350-572: The last 14 million years. Concentrations of methane are far higher than they were over the last 800,000 years. Global human-caused greenhouse gas emissions in 2019 were equivalent to 59 billion tonnes of CO 2 . Of these emissions, 75% was CO 2 , 18% was methane , 4% was nitrous oxide, and 2% was fluorinated gases . CO 2 emissions primarily come from burning fossil fuels to provide energy for transport , manufacturing, heating , and electricity. Additional CO 2 emissions come from deforestation and industrial processes , which include

9460-436: The last two decades. CO 2 is only removed from the atmosphere for the long term when it is stored in the Earth's crust, which is a process that can take millions of years to complete. Around 30% of Earth's land area is largely unusable for humans ( glaciers , deserts , etc.), 26% is forests , 10% is shrubland and 34% is agricultural land . Deforestation is the main land use change contributor to global warming, as

9570-441: The last: internal climate variability processes can make any year 0.2 °C warmer or colder than the average. From 1998 to 2013, negative phases of two such processes, Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) caused a short slower period of warming called the " global warming hiatus ". After the "hiatus", the opposite occurred, with years like 2023 exhibiting temperatures well above even

9680-608: The lower atmosphere. Carbon dioxide , the primary greenhouse gas driving global warming, has grown by about 50% and is at levels not seen for millions of years. Climate change has an increasingly large impact on the environment . Deserts are expanding , while heat waves and wildfires are becoming more common. Amplified warming in the Arctic has contributed to thawing permafrost , retreat of glaciers and sea ice decline . Higher temperatures are also causing more intense storms , droughts, and other weather extremes . Rapid environmental change in mountains , coral reefs , and

9790-444: The majority of the carbon dioxide is not converted into carbonic acid, but remains as CO 2 molecules, not affecting the pH. The relative concentrations of CO 2 , H 2 CO 3 , and the deprotonated forms HCO − 3 ( bicarbonate ) and CO 2− 3 ( carbonate ) depend on the pH . As shown in a Bjerrum plot , in neutral or slightly alkaline water (pH > 6.5), the bicarbonate form predominates (>50%) becoming

9900-526: The manufacturer, the AQE is one of the few de facto commercially available, comprehensive Internet of Things pollution monitors on the US market. A number of competing devices have been announced, such as Chemisense Wearable and Foobot (formerly Alima). Another US crowdsourced air quality monitoring device is CitizenSensor, but it is listed an outgoing project, DIY, and not available for purchase. A comprehensive Internet of Things air pollution monitoring device

10010-413: The more popular term after NASA climate scientist James Hansen used it in his 1988 testimony in the U.S. Senate . Since the 2000s, climate change has increased usage. Various scientists, politicians and media may use the terms climate crisis or climate emergency to talk about climate change, and may use the term global heating instead of global warming . Over the last few million years

10120-443: The most prevalent (>95%) at the pH of seawater. In very alkaline water (pH > 10.4), the predominant (>50%) form is carbonate. The oceans, being mildly alkaline with typical pH = 8.2–8.5, contain about 120 mg of bicarbonate per liter. Being diprotic , carbonic acid has two acid dissociation constants , the first one for the dissociation into the bicarbonate (also called hydrogen carbonate) ion ( HCO − 3 ): This

10230-479: The outdoor concentration is 400 ppm, indoor concentrations may reach 2,500 ppm with ventilation rates that meet this industry consensus standard. Concentrations in poorly ventilated spaces can be found even higher than this (range of 3,000 or 4,000 ppm). Climate change Present-day climate change includes both global warming —the ongoing increase in global average temperature —and its wider effects on Earth's climate . Climate change in

10340-495: The presence of carbon dioxide in water also affects its electrical properties. When carbon dioxide dissolves in desalinated water, the electrical conductivity increases significantly from below 1 μS/cm to nearly 30 μS/cm. When heated, the water begins to gradually lose the conductivity induced by the presence of C O 2 {\displaystyle \mathrm {CO_{2}} } , especially noticeable as temperatures exceed 30 °C. The temperature dependence of

10450-499: The presence of sufficient oxygen, manifesting as dizziness, headache, visual and hearing dysfunction, and unconsciousness within a few minutes to an hour. Concentrations of more than 10% may cause convulsions, coma, and death. CO 2 levels of more than 30% act rapidly leading to loss of consciousness in seconds. Because it is heavier than air, in locations where the gas seeps from the ground (due to sub-surface volcanic or geothermal activity) in relatively high concentrations, without

10560-496: The products of their photosynthesis as internal food sources and as raw material for the biosynthesis of more complex organic molecules, such as polysaccharides , nucleic acids , and proteins. These are used for their own growth, and also as the basis of the food chains and webs that feed other organisms, including animals such as ourselves. Some important phototrophs, the coccolithophores synthesise hard calcium carbonate scales. A globally significant species of coccolithophore

10670-619: The rate at which heat escapes into space, trapping heat near the Earth's surface and warming it over time. While water vapour (≈50%) and clouds (≈25%) are the biggest contributors to the greenhouse effect, they primarily change as a function of temperature and are therefore mostly considered to be feedbacks that change climate sensitivity . On the other hand, concentrations of gases such as CO 2 (≈20%), tropospheric ozone , CFCs and nitrous oxide are added or removed independently from temperature, and are therefore considered to be external forcings that change global temperatures. Before

10780-522: The rate of Arctic shrinkage and underestimated the rate of precipitation increase. Sea level rise since 1990 was underestimated in older models, but more recent models agree well with observations. The 2017 United States-published National Climate Assessment notes that "climate models may still be underestimating or missing relevant feedback processes". Additionally, climate models may be unable to adequately predict short-term regional climatic shifts. A subset of climate models add societal factors to

10890-622: The rate of yield growth . Fisheries have been negatively affected in multiple regions. While agricultural productivity has been positively affected in some high latitude areas, mid- and low-latitude areas have been negatively affected. According to the World Economic Forum, an increase in drought in certain regions could cause 3.2 million deaths from malnutrition by 2050 and stunting in children. With 2 °C warming, global livestock headcounts could decline by 7–10% by 2050, as less animal feed will be available. If

11000-405: The recent average. This is why the temperature change is defined in terms of a 20-year average, which reduces the noise of hot and cold years and decadal climate patterns, and detects the long-term signal. A wide range of other observations reinforce the evidence of warming. The upper atmosphere is cooling, because greenhouse gases are trapping heat near the Earth's surface, and so less heat

11110-411: The release of chemical compounds that influence clouds, and by changing wind patterns. In tropic and temperate areas the net effect is to produce significant warming, and forest restoration can make local temperatures cooler. At latitudes closer to the poles, there is a cooling effect as forest is replaced by snow-covered (and more reflective) plains. Globally, these increases in surface albedo have been

11220-476: The remaining 23%. Some forests have not been fully cleared, but were already degraded by these impacts. Restoring these forests also recovers their potential as a carbon sink. Local vegetation cover impacts how much of the sunlight gets reflected back into space ( albedo ), and how much heat is lost by evaporation . For instance, the change from a dark forest to grassland makes the surface lighter, causing it to reflect more sunlight. Deforestation can also modify

11330-420: The same amount of protein. The concentration of secondary metabolites such as phenylpropanoids and flavonoids can also be altered in plants exposed to high concentrations of CO 2 . Plants also emit CO 2 during respiration, and so the majority of plants and algae, which use C3 photosynthesis , are only net absorbers during the day. Though a growing forest will absorb many tons of CO 2 each year,

11440-411: The same frequency and same energy, because of the symmetry of the molecule. When a molecule touches a surface or touches another molecule, the two bending modes can differ in frequency because the interaction is different for the two modes. Some of the vibrational modes are observed in the infrared (IR) spectrum : the antisymmetric stretching mode at wavenumber 2349 cm (wavelength 4.25 μm) and

11550-583: The sea levels by at least 3.3 m (10 ft 10 in) over approximately 2000 years. Recent warming has driven many terrestrial and freshwater species poleward and towards higher altitudes . For instance, the range of hundreds of North American birds has shifted northward at an average rate of 1.5 km/year over the past 55 years. Higher atmospheric CO 2 levels and an extended growing season have resulted in global greening. However, heatwaves and drought have reduced ecosystem productivity in some regions. The future balance of these opposing effects

11660-535: The upper ocean and thereby promotes the absorption of CO 2 from the atmosphere. Carbon dioxide content in fresh air (averaged between sea-level and 10 kPa level, i.e., about 30 km (19 mi) altitude) varies between 0.036% (360 ppm) and 0.041% (412 ppm), depending on the location. In humans, exposure to CO 2 at concentrations greater than 5% causes the development of hypercapnia and respiratory acidosis . Concentrations of 7% to 10% (70,000 to 100,000 ppm) may cause suffocation, even in

11770-546: The water, or to the lungs from where it is exhaled. During active photosynthesis, plants can absorb more carbon dioxide from the atmosphere than they release in respiration. Carbon fixation is a biochemical process by which atmospheric carbon dioxide is incorporated by plants, algae and cyanobacteria into energy-rich organic molecules such as glucose , thus creating their own food by photosynthesis. Photosynthesis uses carbon dioxide and water to produce sugars from which other organic compounds can be constructed, and oxygen

11880-438: The world. Impacts can be observed on all continents and ocean regions, with low-latitude, less developed areas facing the greatest risk. Continued warming has potentially "severe, pervasive and irreversible impacts" for people and ecosystems. The risks are unevenly distributed, but are generally greater for disadvantaged people in developing and developed countries. The World Health Organization calls climate change one of

11990-503: Was conceived at a Parsons/New School hackathon. It is manufactured and sold by the start-up company WickedDevice LLC in Ithaca, NY. The name "Air Quality Egg" was created by company co-founder Dirk Swart. Originally, there were two versions of the device: an Arduino shield for use by hobbyists, and a more consumer-ready "hobbyist kit" device. The latter consists of two identical-looking plastic enclosures resembling white eggs. The base unit

12100-524: Was sending more energy to Earth, but instead, it has been cooling. This is consistent with greenhouse gases preventing heat from leaving the Earth's atmosphere. Explosive volcanic eruptions can release gases, dust and ash that partially block sunlight and reduce temperatures, or they can send water vapour into the atmosphere, which adds to greenhouse gases and increases temperatures. These impacts on temperature only last for several years, because both water vapour and volcanic material have low persistence in

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