The following is our Climate Change Frequently Asked Questions (FAQs)  list with answers provided by extracting the relevant 98 answers from Wikipedia. We hope you find it useful, and welcome feedback comments on accuracy and suggested modifications. (All answers were curated from Wikipedia content as current in January 2020.)

What is AbandonmentEnvironmental migrants or climate refugees are people who are forced to leave their home region due to sudden or longterm changes to their local environment. These are changes which compromise their wellbeing or secure livelihood. Such changes are held to include increased droughts, desertification, sea level rise, and disruption of seasonal weather patterns. Climate refugees may choose to flee to or migrate to another country, or they may migrate internally within their own country.[2]
What is Abrupt Climate ChangeAn abrupt climate change occurs when the climate system is forced to transition to a new climate state at a rate that is determined by the climate system energybalance, and which is more rapid than the rate of change of the external forcing. Past events include the end of the Carboniferous Rainforest Collapse, Younger Dryas, DansgaardOeschger events, Heinrich events and possibly also the Paleocene?Eocene Thermal Maximum. The term is also used within the context of global warming to describe sudden climate change that is detectable over the timescale of a human lifetime, possibly as the result of feedback loops within the climate system.
What is AdaptationClimate change adaptation (CCA) is a response to global warming. The Intergovernmental Panel on Climate Change (IPCC) defines adaptation as: 'the process of adjustment to actual or expected climate and its effects. In human systems, adaptation seeks to moderate or avoid harm or exploit beneficial opportunities. In some natural systems, human intervention may facilitate adjustment to expected climate and its effects'. This adjustment includes many areas such as infrastructure, agriculture and education.
What is the AlbedoAlbedo is the measure of the diffuse reflection of solar radiation out of the total solar radiation received by an astronomical body. It is dimensionless and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body that reflects all incident radiation.
What is an EcosystemAn ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the system through photosynthesis and is incorporated into plant tissue. By feeding on plants and on oneanother, animals play an important role in the movement of matter and energy through the system. They also influence the quantity of plant and microbial biomass present. By breaking down dead organic matter, decomposers release carbon back to the atmosphere and facilitate nutrient cycling by converting nutrients stored in dead biomass back to a form that can be readily used by plants and other microbes.
What is Arctic AmplificationPolar amplification is the phenomenon that any change in the net radiation balance tends to produce a larger change in temperature near the poles than the planetary average. On a planet with an atmosphere that can restrict emission of longwave radiation to space, surface temperatures will be warmer than a simple planetary equilibrium temperature calculation would predict. Where the atmosphere or an extensive ocean is able to transport heat polewards, the poles will be warmer and equatorial regions cooler than their local net radiation balances would predict.
What is the AtmosphereAn atmosphere is a layer or a set of layers of gases surrounding a planet or other material body, that is held in place by the gravity of that body. An atmosphere is more likely to be retained if the gravity it is subject to is high and the temperature of the atmosphere is low.
What are Atmospheric Brown CloudsThe Indian Ocean brown cloud or Asian brown cloud is a layer of air pollution that recurrently covers parts of South Asia, namely the northern Indian Ocean, India, and Pakistan. Viewed from satellite photos, the cloud appears as a giant brown stain hanging in the air over much of South Asia and the Indian Ocean every year between January and March, possibly also during earlier and later months. The term was coined in reports from the UNEP Indian Ocean Experiment (INDOEX).
What is the Atmospheric LifetimeA greenhouse gas (sometimes abbreviated GHG) is a gas that absorbs and emits radiant energy within the thermal infrared range. Greenhouse gases cause the greenhouse effect on planets. The primary greenhouse gases in Earth's atmosphere are water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3). Without greenhouse gases, the average temperature of Earth's surface would be about ?18C (0F), rather than the present average of 15C (59F). The atmospheres of Venus, Mars and Titan also contain greenhouse gases.
What is Black CarbonChemically, black carbon (BC) is a component of fine particulate matter. Black carbon consists of pure carbon in several linked forms. It is formed through the incomplete combustion of fossil fuels, biofuel, and biomass, and is emitted in both anthropogenic and naturally occurring soot. Black carbon causes human morbidity and premature mortality.
What is the Carbon CycleThe carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere, and atmosphere of the Earth. Carbon is the main component of biological compounds as well as a major component of many minerals such as limestone. Along with the nitrogen cycle and the water cycle, the carbon cycle comprises a sequence of events that are key to make Earth capable of sustaining life. It describes the movement of carbon as it is recycled and reused throughout the biosphere, as well as longterm processes of carbon sequestration to and release from carbon sinks.
What is Carbon DioxideCarbon dioxide is a colorless gas with a density about 60% higher than that of dry air. 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. The current concentration is about 0.04% (410ppm) by volume, having risen from preindustrial levels of 280ppm. 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. Carbon dioxide is odorless at normally encountered concentrations, but at high concentrations, it has a sharp and acidic odor.
What is a Carbon FootprintA carbon footprint is historically defined as the total greenhouse gas (GHG) emissions caused by an individual, event, organization, or product, expressed as carbon dioxide equivalent. Greenhouse gases, including the carboncontaining gases carbon dioxide and methane, can be emitted through the burning of fossil fuels, land clearance and the production and consumption of food, manufactured goods, materials, wood, roads, buildings, transportation and other services.
What is the Carbon SinkA carbon sink is a natural reservoir that stores carboncontaining chemical compounds accumulated over an indefinite period of time. Public awareness of the significance of CO2 sinks has grown since passage of the Kyoto Protocol, which promotes their use as a form of carbon offset. There are also different strategies used to enhance this process.
What is Carbon TaxA carbon tax is a tax levied on the carbon content of fuels and, like carbon emissions trading, is a form of carbon pricing. The term carbon tax is also used to refer to a carbon dioxide equivalent tax, the latter of which is quite similar but can be placed on any type of greenhouse gas or combination of greenhouse gases, emitted by any economic sector.
What are CFCsChlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly halogenated paraffin hydrocarbons that contain only carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F), produced as volatile derivative of methane, ethane, and propane. They are also commonly known by the DuPont brand name Freon.
What is Clean TechnologyClean technology is any process, product, or service that reduces negative environmental impacts through significant energy efficiency improvements, the sustainable use of resources, or environmental protection activities. Clean technology includes a broad range of technology related to recycling, renewable energy, information technology, green transportation, electric motors, green chemistry, lighting, Greywater, and more. Environmental finance is a method by which new clean technology projects that have proven that they are "additional" or "beyond business as usual" can obtain financing through the generation of carbon credits. A project that is developed with concern for climate change mitigation is also known as a carbon project.
What is Climate ChangeClimate change occurs when changes in Earth's climate system result in new weather patterns that remain in place for an extended period of time. This length of time can be as short as a few decades to as long as millions of years. Scientists have identified many episodes of climate change during Earth's geological history; more recently since the industrial revolution the climate has increasingly been affected by human activities driving global warming, and the terms are commonly used interchangeably in that context.
What is Climate EngineeringClimate engineering or climate intervention, commonly referred to as geoengineering, is the deliberate and largescale intervention in the Earth's climate system, usually with the aim of mitigating the adverse effects of global warming. The most prominent subcategory of climate engineering is solar radiation management. Solar radiation management attempts to offset the effects of greenhouse gases by causing the Earth to absorb less solar radiation. Almost all research into solar radiation management has to date consisted of computer modelling or laboratory tests, and an attempt to move to outdoor experimentation has proven controversial.
What are Climate Feedback EffectsClimate sensitivity is the globally averaged temperature change in response to changes in radiative forcing, which can occur, for instance, due to increased levels of carbon dioxide (CO2). Although the term climate sensitivity is usually used in the context of radiative forcing by CO2, it is thought of as a general property of the climate system: the change in surface air temperature following a unit change in radiative forcing, and the climate sensitivity parameter is therefore expressed in units of C/(W/m2). The measure is approximately independent of the nature of the forcing (e.g. from greenhouse gases or solar variation). When climate sensitivity is expressed for a doubling of CO2, its units are degrees Celsius (C).
What is a Climate ModelNumerical Climate models use quantitative methods to simulate the interactions of the important drivers of climate, including atmosphere, oceans, land surface and ice. They are used for a variety of purposes from study of the dynamics of the climate system to projections of future climate. Climate models may also be qualitative models and also narratives, largely descriptive, of possible futures.
What is the Climate SystemEarth's climate arises from the interaction of five major climate system components: the atmosphere (air), the hydrosphere (water), the cryosphere, the lithosphere and the biosphere. Climate is the average weather, typically over a period of 30 years, and is determined by a combination of processes in the climate system, such as ocean currents and wind patterns. Circulation in the atmosphere and oceans is primarily driven by solar radiation and transports heat from the tropical regions to regions that receive less energy from the Sun. The water cycle also moves energy throughout the climate system. In addition, different chemical elements, necessary for life, are constantly recycled between the different components.
What is the Copenhagen AccordThe Copenhagen Accord is a document which delegates at the 15th session of the Conference of Parties to the United Nations Framework Convention on Climate Change agreed to "take note of" at the final plenary on 18 December 2009.
What are Coral ReefsHuman impact on coral reefs is significant. Coral reefs are dying around the world. Damaging activities include coral mining, pollution, overfishing, blast fishing, the digging of canals and access into islands and bays. Other dangers include disease, destructive fishing practices and warming oceans. Factors that affect coral reefs include the ocean's role as a carbon dioxide sink, atmospheric changes, ultraviolet light, ocean acidification, viruses, impacts of dust storms carrying agents to farflung reefs, pollutants, algal blooms and others. Reefs are threatened well beyond coastal areas. Climate change, such as warming temperatures, causes coral bleaching, which if severe kills the coral.
What are Crop FailuresHarvesting is the process of gathering a ripe crop from the fields. Reaping is the cutting of grain or pulse for harvest, typically using a scythe, sickle, or reaper. On smaller farms with minimal mechanization, harvesting is the most laborintensive activity of the growing season. On large mechanized farms, harvesting utilizes the most expensive and sophisticated farm machinery, such as the combine harvester. Process automation has increased the efficiency of both the seeding and harvesting process. Specialized harvesting equipment utilizing conveyor belts to mimic gentle gripping and mass transport replaces the manual task of removing each seedling by hand. The term "harvesting" in general usage may include immediate postharvest handling, including cleaning, sorting, packing, and cooling.
What is Crop ProductionAgricultural productivity is measured as the ratio of agricultural outputs to agricultural inputs. While individual products are usually measured by weight, their varying densities make measuring overall agricultural output difficult. Therefore, output is usually measured as the market value of final output, which excludes intermediate products such as corn feed used in the meat industry. This output value may be compared to many different types of inputs such as labour and land. These are called partial measures of productivity.
What is DeforestationDeforestation is one of the main contributors to climate change. It comes in many forms: wildfire, agricultural clearcutting, livestock ranching, and logging for timber, among others. Forests cover 31% of the land area on Earth and annually 75,700 square kilometers of forest is lost. Mass deforestation continues to threaten tropical forests, their biodiversity and the ecosystem services they provide. The main area of concern of deforestation is in tropical rainforests, since it is home to the majority of the biodiversity. Organisations such as World Wildlife Fund focus on the preservation of nature and the reduction of the most pressing threats to the diversity of life on Earth.
What are Developing CountriesA developing country is a country with a less developed industrial base and a low Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreement on which countries fit this category. A nation's GDP per capita compared with other nations can also be a reference point. In general, the United Nations accepts any country's claim of itself being "developing".
What is the Dominant CauseAttribution of recent climate change is the effort to scientifically ascertain mechanisms responsible for recent global warming and related climate changes on Earth. The effort has focused on changes observed during the period of instrumental temperature record, particularly in the last 50 years. This is the period when human activity has grown fastest and observations of the atmosphere above the surface have become available. According to the Intergovernmental Panel on Climate Change (IPCC), it is "extremely likely" that human influence was the dominant cause of global warming between 1951 and 2010. The best estimate is that observed warming since 1951 has been entirely human caused.
What are DroughtsA drought or drouth is an event of prolonged shortages in the water supply, whether atmospheric, surface water or ground water. A drought can last for months or years, or may be declared after as few as 15 days. It can have a substantial impact on the ecosystem and agriculture of the affected region and harm to the local economy. Annual dry seasons in the tropics significantly increase the chances of a drought developing and subsequent bush fires. Periods of heat can significantly worsen drought conditions by hastening evaporation of water vapour.
What is Economic GrowthEconomic growth is the increase in the inflationadjusted market value of the goods and services produced by an economy over time. It is conventionally measured as the percent rate of increase in real gross domestic product, or real GDP.
What are EcosystemsClimate change has adversely affected both terrestrial and marine ecosystems. Future climate change is expected to further affect many ecosystems, including tundra, mangroves, coral reefs, and caves.
What are the Effects Of Global WarmingThe effects of global warming include farreaching and longlasting changes to the natural environment, to ecosystems and human societies caused directly or indirectly by human emissions of greenhouse gases. It also includes the economic and social changes which stem from living in a warmer world and the responses to those changes.
What is Emissions TradingEmissions trading is a marketbased approach to controlling pollution by providing economic incentives for achieving reductions in the emissions of pollutants.
What is Energy EfficiencyEfficient energy use, sometimes simply called energy efficiency, is the goal to reduce the amount of energy required to provide products and services. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature. Installing LED lighting, fluorescent lighting, or natural skylight windows reduces the amount of energy required to attain the same level of illumination compared to using traditional incandescent light bulbs. Improvements in energy efficiency are generally achieved by adopting a more efficient technology or production process or by application of commonly accepted methods to reduce energy losses.
What is EvaporationEvaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. The surrounding gas must not be saturated with the evaporating substance. When the molecules of the liquid collide, they transfer energy to each other based on how they collide with each other. When a molecule near the surface absorbs enough energy to overcome the vapor pressure, it will escape and enter the surrounding air as a gas. When evaporation occurs, the energy removed from the vaporized liquid will reduce the temperature of the liquid, resulting in evaporative cooling.
What is the Expansion Of DesertsDesertification is a type of land degradation in drylands involving loss of biological productivity caused by natural processes or induced by human activities. It is caused by a variety of factors, such as through climate change and through the overexploitation of soil through human activity. When deserts appear automatically over the natural course of a planet's life cycle, then it can be called a natural phenomenon; however, when deserts emerge due to the rampant and unchecked depletion of nutrients in soil that are essential for it to remain arable, then a virtual "soil death" can be spoken of, which traces its cause back to human overexploitation. Desertification is a significant global ecological and environmental problem with far reaching consequences on socioeconomic and political conditions.
What is ExtinctionThe extinction risk of global warming is the risk of species becoming extinct due to the effects of global warming. This may be Earth's sixth major extinction, often called the Anthropocene or Holocene extinction.
What is Extinction RebellionExtinction Rebellion is a global environmental movement with the stated aim of using nonviolent civil disobedience to compel government action to avoid tipping points in the climate system, biodiversity loss, and the risk of social and ecological collapse.
What is Extreme WeatherExtreme weather includes unexpected, unusual, unpredictable, severe, or unseasonal weather; weather at the extremes of the historical distribution?the range that has been seen in the past. Often, extreme events are based on a location's recorded weather history and defined as lying in the most unusual ten percent. In recent years some extreme weather events have been attributed to humaninduced global warming, with studies indicating an increasing threat from extreme weather in the future.
What is the Fifth Assessment ReportThe Fifth Assessment Report (AR5) of the United Nations Intergovernmental Panel on Climate Change (IPCC) is the fifth in a series of such reports. The IPCC was established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) to assess scientific, technical and socioeconomic information concerning climate change, its potential effects and options for adaptation and mitigation.
What are Fluorinated GasesFluorinated gases (Fgases) are manmade gases that can stay in the atmosphere for centuries and contribute to a global greenhouse effect. There are four types: hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6) and nitrogen trifluoride (NF3).
What is Food SecurityClimate change and agriculture are interrelated processes, both of which take place on a global scale. Global warming affects agriculture in a number of ways, including through changes in average temperatures, rainfall, and climate extremes ; changes in pests and diseases; changes in atmospheric carbon dioxide and groundlevel ozone concentrations; changes in the nutritional quality of some foods; and changes in sea level.
What is Global DimmingGlobal dimming is the reduction in the amount of global direct irradiance at the Earth's surface that has been observed since systematic measurements began in the 1950s. The effect varies by location, but worldwide it has been estimated to be of the order of a 420% reduction. However, after discounting an anomaly caused by the eruption of Mount Pinatubo in 1991, a very slight reversal in the overall trend has been observed.
What is a Glacial Lake Outburst Flood (GLOF)A glacial lake outburst flood (GLOF) is a type of outburst flood that occurs when the dam containing a glacial lake fails. An event similar to a GLOF, where a body of water contained by a glacier melts or overflows the glacier, is called a Jökulhlaup. The dam can consist of glacier ice or a terminal moraine. Failure can happen due to erosion, a buildup of water pressure, an avalanche of rock or heavy snow, an earthquake or cryoseism, volcanic eruptions under the ice, or if a large enough portion of a glacier breaks off and massively displaces the waters in a glacial lake at its base.
What is Global Mean Sea Level RiseSince at least the start of the 20th century, the average global sea level has been rising. Between 1900 and 2016, the sea level rose by 16?21cm (6.3?8.3in). More precise data gathered from satellite radar measurements reveal an accelerating rise of 7.5cm (3.0in) from 1993 to 2017, which is a trend of roughly 30cm (12in) per century. This acceleration is due mostly to humancaused global warming, which is driving thermal expansion of seawater and the melting of landbased ice sheets and glaciers. Between 1993 and 2018, thermal expansion of the oceans contributed 42% to sea level rise; the melting of temperate glaciers, 21%; Greenland, 15%; and Antarctica, 8%. Climate scientists expect the rate to further accelerate during the 21st century.
What is a Global Warming HiatusA global warming hiatus, also sometimes referred to as a global warming pause or a global warming slowdown, is a period of relatively little change in globally averaged surface temperatures. In the current episode of global warming many such 15year periods appear in the surface temperature record, along with robust evidence of the longterm warming trend. Such a "hiatus" is shorter than the 30year periods that climate is classically averaged over.
What are Global Warming PotentialsGlobal warming potential (GWP) is a measure of how much heat a greenhouse gas traps in the atmosphere up to a specific time horizon, relative to carbon dioxide. It compares the amount of heat trapped by a certain mass of the gas in question to the amount of heat trapped by a similar mass of carbon dioxide and is expressed as a factor of carbon dioxide.
What are Greatest Annual CO2 EmittersThis is a list of sovereign states and territories by carbon dioxide emissions due to certain forms of human activity, based on the EDGAR database created by European Commission and Netherlands Environmental Assessment Agency released in 2018. The following table lists the 1990, 2005 and 2017 annual CO2 emissions estimates along with a list of calculated emissions per km and emissions per capita.
What are Greenhouse GasesA greenhouse gas (sometimes abbreviated GHG) is a gas that absorbs and emits radiant energy within the thermal infrared range. Greenhouse gases cause the greenhouse effect on planets. The primary greenhouse gases in Earth's atmosphere are water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and ozone (O3). Without greenhouse gases, the average temperature of Earth's surface would be about ?18C (0F), rather than the present average of 15C (59F). The atmospheres of Venus, Mars and Titan also contain greenhouse gases.
What is the Gulf StreamThe Gulf Stream, together with its northern extension the North Atlantic Drift, is a warm and swift Atlantic ocean current that originates in the Gulf of Mexico and stretches to the tip of Florida, and follows the eastern coastlines of the United States and Newfoundland before crossing the Atlantic Ocean as the North Atlantic Current. The process of western intensification causes the Gulf Stream to be a northwards accelerating current off the east coast of North America. At about 400?N 300?W, it splits in two, with the northern stream, the North Atlantic Drift, crossing to Northern Europe and the southern stream, the Canary Current, recirculating off West Africa.
What is the Heat Content Of The OceansThe improper expression Oceanic Heat Content (OHC) refers to the heat absorbed by the ocean, which is then stored as a form of internal energy or enthalpy. Oceanography and climatology are the science branches which study ocean heat content. Changes in the ocean heat content play an important role in the sea level rise, because of thermal expansion. It is with high confidence that ocean warming accounts for 90% of the energy accumulation from global warming between 1971 and 2010. About one third of that extra heat has been estimated to propagate to depth below 700 meters. Beyond the direct impact of thermal expansion, ocean warming contributes to increased rates of ice melt of glaciers in fjords of Greenland and ice sheets in Antarctica. Warmer Oceans are also responsible for coral bleaching.
What are Heat WavesA heat wave, or heatwave, is a period of excessively hot weather, which may be accompanied by high humidity, especially in oceanic climate countries. While definitions vary, a heat wave is usually measured relative to the usual weather in the area and relative to normal temperatures for the season. Temperatures that people from a hotter climate consider normal can be called a heat wave in a cooler area if they are outside the normal climate pattern for that area.
What is the Hothouse Climate StateThroughout the history of the Earth, the planet's climate has been fluctuating between two dominant climate states: the greenhouse Earth and the icehouse Earth. These two climate states last for millions of years and should not be confused with glacial and interglacial periods, which occur only during an icehouse period and tend to last less than 1 million years. There are five known great glaciations in Earth's climate history; the main factors involved in changes of the paleoclimate are believed to be the concentration of atmospheric carbon dioxide, changes in the Earth's orbit, longterm changes in the solar constant, and oceanic and orogenic changes due to tectonic plate dynamics. Greenhouse and icehouse periods have profoundly shaped the evolution of life on Earth.
What is HumidityHumidity is the concentration of water vapour present in air. Water vapour, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. The amount of water vapour needed to achieve saturation increases as the temperature increases. As the temperature of a parcel of air decreases it will eventually reach the saturation point without adding or losing water mass. The amount of water vapour contained within a parcel of air can vary significantly. For example, a parcel of air near saturation may contain 28 grams of water per cubic metre of air at 30C, but only 8 grams of water per cubic metre of air at 8C.
Are Hurricanes And Typhoons Changing?Tropical cyclones and climate change concerns how tropical cyclones have changed, and are expected to further change due to climate change. The topic receives considerable attention from climate scientists who study the connections between storms and climate, and notably since 2005 makes news during active storm seasons. The 2018 U.S. National Climate Change Assessment reported that "increases in greenhouse gases and decreases in air pollution have contributed to increases in Atlantic hurricane activity since 1970."
What was the Industrial RevolutionThe Industrial Revolution, now also known as the First Industrial Revolution, was the transition to new manufacturing processes in Europe and the United States, in the period from about 1760 to sometime between 1820 and 1840. This transition included going from hand production methods to machines, new chemical manufacturing and iron production processes, the increasing use of steam power and water power, the development of machine tools and the rise of the mechanized factory system. The Industrial Revolution also led to an unprecedented rise in the rate of population growth.
What is the Intergovernmental Panel On Climate ChangeThe Intergovernmental Panel on Climate Change (IPCC) is an intergovernmental body of the United Nations that is dedicated to providing the world with objective, scientific information relevant to understanding the scientific basis of the risk of humaninduced climate change, its natural, political, and economic impacts and risks, and possible response options.
What is the IPCC Fifth Assessment ReportThe Fifth Assessment Report (AR5) of the United Nations Intergovernmental Panel on Climate Change (IPCC) is the fifth in a series of such reports. The IPCC was established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) to assess scientific, technical and socioeconomic information concerning climate change, its potential effects and options for adaptation and mitigation.
What is the Jet StreamJet streams are fast flowing, narrow, meandering air currents in the atmospheres of some planets, including Earth. On Earth, the main jet streams are located near the altitude of the tropopause and are westerly winds. Their paths typically have a meandering shape. Jet streams may start, stop, split into two or more parts, combine into one stream, or flow in various directions including opposite to the direction of the remainder of the jet.
What is the Kyoto ProtocolThe Kyoto Protocol is an international treaty which extends the 1992 United Nations Framework Convention on Climate Change (UNFCCC) that commits state parties to reduce greenhouse gas emissions, based on the scientific consensus that (part one) global warming is occurring and (part two) it is extremely likely that humanmade CO2 emissions have predominantly caused it. The Kyoto Protocol was adopted in Kyoto, Japan, on 11 December 1997 and entered into force on 16 February 2005. There are currently 192 parties (Canada withdrew from the protocol, effective December 2012) to the Protocol.
What a Life-Cycle AssessmentLifecycle assessment is a technique to assess environmental impacts associated with all the stages of the lifecycle of a commercial product, process, or service, e.g., in the case of a manufactured product, from raw material extraction and processing (cradle), through the product's manufacture, distribution and use, to the recycling or final disposal of the materials composing it (grave).
What was the Little Ice AgeThe Little Ice Age (LIA) was a period of cooling that occurred after the Medieval Warm Period. Although it was not a true ice age, the term was introduced into scientific literature by Franois E. Matthes in 1939. It has been conventionally defined as a period extending from the 16th to the 19th centuries, but some experts prefer an alternative timespan from about 1300 to about 1850.
What are the Long-Term Effects Of Global WarmingThere are expected to be various long term effects of global warming. Most discussion and research, including that by the Intergovernmental Panel on Climate Change (IPCC) reports, concentrates on the effects of global warming up to 2100, with only an outline of the effects beyond this.
What is Mauna LoaThe Mauna Loa Observatory (MLO) is an atmospheric baseline station on Mauna Loa, on the island of Hawaii, located in the U.S. state of Hawaii.
What is the Medieval Climate AnomalyThe Medieval Warm Period (MWP) also known as the Medieval Climate Optimum, or Medieval Climatic Anomaly was a time of warm climate in the North Atlantic region lasting from c.?950 to c.?1250. It was likely related to warming elsewhere while some other regions were colder, such as the tropical Pacific. Average global mean temperatures have been calculated to be similar to earlymid20thcentury warming. Possible causes of the Medieval Warm Period include increased solar activity, decreased volcanic activity, and changes to ocean circulation.
What is MethaneMethane (or ) is a chemical compound with the chemical formula CH4 (one atom of carbon and four atoms of hydrogen). It is a group14 hydride and the simplest alkane, and is the main constituent of natural gas. The relative abundance of methane on Earth makes it an attractive fuel, although capturing and storing it poses challenges due to its gaseous state under normal conditions for temperature and pressure.
What is Climate Change MitigationClimate change mitigation consists of actions to limit the magnitude or rate of longterm global warming and its related effects. Climate change mitigation generally involves reductions in human (anthropogenic) emissions of greenhouse gases (GHGs). Mitigation may also be achieved by increasing the capacity of carbon sinks, e.g., through reforestation. Mitigation policies can substantially reduce the risks associated with humaninduced global warming.
What is the MonsoonMonsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea. Usually, the term monsoon is used to refer to the rainy phase of a seasonally changing pattern, although technically there is also a dry phase. The term is sometimes incorrectly used for locally heavy but shortterm rains.
What are Natural ResourcesNatural resources are resources that exist without actions of humankind. This includes all valued characteristics such as magnetic, gravitational, electrical properties and forces, etc. On Earth it includes sunlight, atmosphere, water, land along with all vegetation, crops and animal life that naturally subsists upon or within the previously identified characteristics and substances.
What is Nitrous OxideNitrous oxide, commonly known as laughing gas or nitrous, is a chemical compound, an oxide of nitrogen with the formula N2O. At room temperature, it is a colourless nonflammable gas, with a slight metallic scent and taste. At elevated temperatures, nitrous oxide is a powerful oxidizer similar to molecular oxygen. It is soluble in water.
What is Ocean AcidificationOcean acidification is the ongoing decrease in the pH of the Earth's oceans, caused by the uptake of carbon dioxide (CO2) from the atmosphere. Seawater is slightly basic (meaning pH > 7), and ocean acidification involves a shift towards pHneutral conditions rather than a transition to acidic conditions (pH < 7). An estimated 30?40% of the carbon dioxide from human activity released into the atmosphere dissolves into oceans, rivers and lakes. To achieve chemical equilibrium, some of it reacts with the water to form carbonic acid. Some of the resulting carbonic acid molecules dissociate into a bicarbonate ion and a hydrogen ion, thus increasing ocean acidity (H+ ion concentration). Between 1751 and 1996, surface ocean pH is estimated to have decreased from approximately 8.25 to 8.14, representing an increase of almost 30% in H+ ion concentration in the world's oceans. Earth System Models project that, by around 2008, ocean acidity exceeded historical analogues and, in combination with other ocean biogeochemical changes, could undermine the functioning of marine ecosystems and disrupt the provision of many goods and services associated with the ocean beginning as early as 2100.
What is Ocean DeoxygenationOcean deoxygenation is the expansion of oxygen minimum zones in the world's oceans as a consequence of anthropogenic emissions of carbon dioxide. The change has been fairly rapid and poses a threat to fish and other types of marine life, as well as to people who depend on marine life for nutrition or livelihood.
What is the Paris AgreementThe Paris Agreement is an agreement within the United Nations Framework Convention on Climate Change (UNFCCC), dealing with greenhousegasemissions mitigation, adaptation, and finance, signed in 2016. The agreement's language was negotiated by representatives of 196 state parties at the 21st Conference of the Parties of the UNFCCC in Le Bourget, near Paris, France, and adopted by consensus on 12 December 2015. As of November 2019, 195 UNFCCC members have signed the agreement, and 187 have become party to it.
What is PermafrostIn geology, permafrost is ground, including rock or (cryotic) soil, with a temperature that remains at or below the freezing point of water 0C (32F) for two or more years. Most permafrost is located in high latitudes, but at lower latitudes alpine permafrost occurs at higher elevations. Ground ice is not always present, as may be in the case of nonporous bedrock, but it frequently occurs, and it may be in amounts exceeding the potential hydraulic saturation of the ground material. Permafrost accounts for 0.022% of total water on Earth, and the permafrost region covers 24% of exposed land in the Northern Hemisphere. It also occurs subsea on the continental shelves of the continents surrounding the Arctic Ocean, portions of which were exposed during the last glacial period.
What are PollutantsA pollutant is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. A pollutant may cause long or shortterm damage by changing the growth rate of plant or animal species, or by interfering with human amenities, comfort, health, or property values. Some pollutants are biodegradable and therefore will not persist in the environment in the long term. However, the degradation products of some pollutants are themselves polluting such as the products DDE and DDD produced from the degradation of DDT.
What is the Post-Glacial ReboundPostglacial rebound is the rise of land masses after the lifting of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Postglacial rebound and isostatic depression are phases of glacial isostasy, the deformation of the Earth's crust in response to changes in ice mass distribution. The direct raising effects of postglacial rebound are readily apparent in parts of Northern Eurasia, Northern America, Patagonia, and Antarctica. However, through the processes of ocean siphoning and continental levering, the effects of postglacial rebound on sea level are felt globally far from the locations of current and former ice sheets.
What is PPMIn science and engineering, the partsper notation is a set of pseudounits to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantityperquantity measures, they are pure numbers with no associated units of measurement. Commonly used are ppm, ppb, ppt and ppq. This notation is not part of the SI system and its meaning is ambiguous.
What is Radiative CoolingRadiative cooling is the process by which a body loses heat by thermal radiation. As Planck's law describes, every physical body spontaneously and continuously emits electromagnetic radiation.
What is Radiative ForcingRadiative forcing or climate forcing is the difference between insolation (sunlight) absorbed by the Earth and energy radiated back to space. Changes to Earth's radiative equilibrium, that cause temperatures to rise or fall over decadal periods, are called climate forcings. Positive radiative forcing means Earth receives more incoming energy from sunlight than it radiates to space. This net gain of energy will cause warming. Conversely, negative radiative forcing means that Earth loses more energy to space than it receives from the sun, which produces cooling. A system in thermal equilibrium has zero radiative forcing.
What is the Rate Of Future Greenhouse Gas EmissionsA Representative Concentration Pathway (RCP) is a greenhouse gas concentration trajectory adopted by the IPCC for its fifth Assessment Report (AR5) in 2014. It supersedes the Special Report on Emissions Scenarios (SRES) projections published in 2000.
What is ReforestationReforestation is the natural or intentional restocking of existing forests and woodlands (forestation) that have been depleted, usually through deforestation. Reforestation can be used to rectify or improve the quality of human life by soaking up pollution and dust from the air, rebuild natural habitats and ecosystems, mitigate global warming since forests facilitate biosequestration of atmospheric carbon dioxide, and harvest for resources, particularly timber, but also nontimber forest products. In the beginning of the 21 century more attention is given to the ability of reforestation to mitigate climate change as one of the best methods to do it.
What is the Retreat Of GlaciersThe retreat of glaciers since 1850 affects the availability of fresh water for irrigation and domestic use, mountain recreation, animals and plants that depend on glaciermelt, and, in the longer term, the level of the oceans. Studied by glaciologists, the temporal coincidence of glacier retreat with the measured increase of atmospheric greenhouse gases is often cited as an evidentiary underpinning of global warming. Midlatitude mountain ranges such as the Himalayas, Alps, Rocky Mountains, Cascade Range, and the southern Andes, as well as isolated tropical summits such as Mount Kilimanjaro in Africa, are showing some of the largest proportionate glacial losses.
What are Rising Sea LevelsSince at least the start of the 20th century, the average global sea level has been rising. Between 1900 and 2016, the sea level rose by 16?21cm (6.3?8.3in). More precise data gathered from satellite radar measurements reveal an accelerating rise of 7.5cm (3.0in) from 1993 to 2017, which is a trend of roughly 30cm (12in) per century. This acceleration is due mostly to humancaused global warming, which is driving thermal expansion of seawater and the melting of landbased ice sheets and glaciers. Between 1993 and 2018, thermal expansion of the oceans contributed 42% to sea level rise; the melting of temperate glaciers, 21%; Greenland, 15%; and Antarctica, 8%. Climate scientists expect the rate to further accelerate during the 21st century.
What is the Scientific ConsensusScientific consensus is the collective judgment, position, and opinion of the community of scientists in a particular field of study. Consensus implies general agreement, though not necessarily unanimity.
What is Sea IceSea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface. Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world's sea ice is enclosed within the polar ice packs in the Earth's polar regions: the Arctic ice pack of the Arctic Ocean and the Antarctic ice pack of the Southern Ocean. Polar packs undergo a significant yearly cycling in surface extent, a natural process upon which depends the Arctic ecology, including the ocean's ecosystems. Due to the action of winds, currents and temperature fluctuations, sea ice is very dynamic, leading to a wide variety of ice types and features. Sea ice may be contrasted with icebergs, which are chunks of ice shelves or glaciers that calve into the ocean. Depending on location, sea ice expanses may also incorporate icebergs.
What is the Shrinking And Thinning Of The Arctic Sea IceIn recent decades, sea ice in the Arctic Ocean has been melting faster than it refreezes in winter. The Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report states that greenhouse gas forcing is predominantly responsible for the decline in Arctic sea ice extent. A 2007 study found the decline to be "faster than forecasted" by model simulations. A 2011 study suggested that this could be reconciled by internal variability enhancing the greenhouse gasforced sea ice decline over the last few decades. A 2012 study with a newer set of simulations also projected rates of retreat which were somewhat less than that actually observed.
What is Shutdown Of Thermohaline CirculationA shutdown or slowdown of the thermohaline circulation is a hypothesized effect of global warming on a major ocean circulation.
What is Solar LuminosityThe solar luminosity (L), is a unit of radiant flux (power emitted in the form of photons) conventionally used by astronomers to measure the luminosity of stars, galaxies and other celestial objects in terms of the output of the Sun. One nominal Solar luminosity is defined by the International Astronomical Union to be 3.8281026W. This does not include the solar neutrino luminosity, which would add 0.023L?. The Sun is a weakly variable star, and its actual luminosity therefore fluctuates. The major fluctuation is the elevenyear solar cycle (sunspot cycle) that causes a periodic variation of about 0.1%. Other variations over the last 200?300 years are thought to be much smaller than this.
What is the StratosphereThe stratosphere is the second major layer of Earth's atmosphere, just above the troposphere, and below the mesosphere. The stratosphere is stratified (layered) in temperature, with warmer layers higher and cooler layers closer to the Earth; this increase of temperature with altitude is a result of the absorption of the Sun's ultraviolet radiation by the ozone layer. This is in contrast to the troposphere, near the Earth's surface, where temperature decreases with altitude. The border between the troposphere and stratosphere, the tropopause, marks where this temperature inversion begins. Near the equator, the lower edge of the stratosphere is as high as 20km, around 10km at midlatitudes, and at about 7km at the poles. Temperatures range from an average of ?51C near the tropopause to an average of ?15C near the mesosphere. Stratospheric temperatures also vary within the stratosphere as the seasons change, reaching particularly low temperatures in the polar night (winter). Winds in the stratosphere can far exceed those in the troposphere, reaching near 60m/s in the Southern polar vortex.
What is Surface TemperatureThe instrumental temperature record provides the temperature of Earth's climate system from the historical network of in situ measurements of surface air temperatures and ocean surface temperatures. Data are collected at thousands of meteorological stations, buoys and ships around the globe. The longestrunning temperature record is the Central England temperature data series, which starts in 1659. The longestrunning quasiglobal record starts in 1850. In recent decades more extensive sampling of ocean temperatures at various depths have begun allowing estimates of ocean heat content but these do not form part of the global surface temperature datasets.
What is Temperature MeasurementsTemperature measurement, also known as thermometry, describes the process of measuring a current local temperature for immediate or later evaluation. Datasets consisting of repeated standardized measurements can be used to assess temperature trends.
What is Thermal InertiaThe volumetric heat capacity of a material is the heat capacity of a sample of the substance divided by the volume of the sample. Informally, it is the amount of energy that must be added, in the form of heat, to one unit of volume of the material in order to cause an increase of one unit in its temperature. The SI unit of volumetric heat capacity is joule per kelvin per cubic meter, J/K/m3 or J/(K m3).
What are Tipping Points In The Climate SystemA tipping point in the climate system is a threshold that, when exceeded, can lead to large changes in the state of the system. Potential tipping points have been identified in the physical climate system, in impacted ecosystems, and sometimes in both. For instance, feedback from the global carbon cycle is a driver for the transition between glacial and interglacial periods, with orbital forcing providing the initial trigger. Earth's geologic temperature record includes many more examples of geologically rapid transitions between different climate states.
What is Tropospheric OzoneOzone (O3) is a trace gas of the troposphere, with an average concentration of 2030 parts per billion by volume (ppbv), with close to 100 ppbv in polluted areas. Ozone is also an important constituent of the stratosphere, where the ozone layer exists which is located between 10 and 50 kilometers about the earths surface. The troposphere is the lowest layer of the Earth's atmosphere. It extends from the ground up to a variable height of approximately 14 kilometers above sea level. Ozone is least concentrated in the ground layer (or planetary boundary layer) of the troposphere. Ground level or tropospheric ozone is created by chemical reactions between oxides of nitrogen (NOx gases) and volatile organic compounds (VOCs). The combination of these chemicals in the presence of sunlight form ozone. Its concentration increases as height above sea level increases, with a maximum concentration at the tropopause. About 90% of total ozone in the atmosphere is in the stratosphere, and 10% is in the troposphere. Although tropospheric ozone is less concentrated than stratospheric ozone, it is of concern because of its health effects. Ozone in the troposphere is considered a greenhouse gas, and may contribute to global warming.
What is the United Nations Framework Convention On Climate ChangeThe United Nations Framework Convention on Climate Change (UNFCCC) is an international environmental treaty adopted on 9 May 1992 and opened for signature at the Earth Summit in Rio de Janeiro from 3 to 14 June 1992. It then entered into force on 21 March 1994, after a sufficient number of countries had ratified it. The UNFCCC objective is to "stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system". The framework sets nonbinding limits on greenhouse gas emissions for individual countries and contains no enforcement mechanisms. Instead, the framework outlines how specific international treaties may be negotiated to specify further action towards the objective of the UNFCCC.
What are the Variations In The Earth's OrbitOrbital forcing is the effect on climate of slow changes in the tilt of the Earth's axis and shape of the orbit. These orbital changes change the total amount of sunlight reaching the Earth by up to 25% at midlatitudes. In this context, the term "forcing" signifies a physical process that affects the Earth's climate.
What are WildfiresA wildfire, wildland fire or rural fire is an uncontrolled fire in an area of combustible vegetation occurring in rural areas. Depending on the type of vegetation present, a wildfire can also be classified more specifically as a brush fire, bushfire, desert fire, forest fire, grass fire, hill fire, peat fire, vegetation fire, or veld fire. Many organizations consider wildfire to mean an unplanned and unwanted fire, while wildland fire is a broader term that includes prescribed fire as well as wildland fire use.

Attribution: The Frequently Asked Questions in the table above were all found at various locations on Wikipedia and have been collated and sorted in Alphabetical Order for ease of reference. To verify any definition provided here refer to Wikipedia.