Glossary

AJAX progress indicator
  • a
  • albedo effect
    is the measure of the diffuse reflection of solar radiation out of the total solar radiation received by an astronomical body (e.g., a planet like Earth). 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. Surface albedo is defined as the ratio of radiosity to the irradiance (flux per unit area) received by a surface.[1] The proportion reflected is not only determined by properties of the surface itself, but also by the spectral and angular distribution of solar radiation reaching the Earth's surface.[2] These factors vary with atmospheric composition, geographic location and time (see position of the Sun). While bi-hemispherical reflectance is calculated for a single angle of incidence (i.e., for a given position of the Sun), albedo is the directional integration of reflectance over all solar angles in a given period. The temporal resolution may range from seconds (as obtained from flux measurements) to daily, monthly, or annual averages. Unless given for a specific wavelength (spectral albedo), albedo refers to the entire spectrum of solar radiation.[3] Due to measurement constraints, it is often given for the spectrum in which most solar energy reaches the surface (between 0.3 and 3 μm). This spectrum includes visible light (0.4–0.7 μm), which explains why surfaces with a low albedo appear dark (e.g., trees absorb most radiation), whereas surfaces with a high albedo appear bright (e.g., snow reflects most radiation). Albedo is an important concept in climatology, astronomy, and environmental management (e.g., as part of the Leadership in Energy and Environmental Design (LEED) program for a sustainable rating of buildings). The average albedo of the Earth from the upper atmosphere, its planetary albedo, is 30–35% because of cloud cover, but widely varies locally across the surface because of different geological and environmental features.[4] The term albedo was introduced into optics by Johann Heinrich Lambert in his 1760 work Photometria.
  • Antarctic
    is a polar region around the Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and other island territories located on the Antarctic Plate or south of the Antarctic Convergence. The Antarctic region includes the ice shelves, waters, and all the island territories in the Southern Ocean situated south of the Antarctic Convergence, a zone approximately 32 to 48 km (20 to 30 mi) wide varying in latitude seasonally.[4] The region covers some 20 percent of the Southern Hemisphere, of which 5.5 percent (14 million km2) is the surface area of the Antarctic continent itself. All of the land and ice shelves south of 60°S latitude are administered under the Antarctic Treaty System. Biogeographically, the Antarctic ecozone is one of eight ecozones of the Earth's land surface.
  • Antarctica
    is a polar region around the Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and other island territories located on the Antarctic Plate or south of the Antarctic Convergence. The Antarctic region includes the ice shelves, waters, and all the island territories in the Southern Ocean situated south of the Antarctic Convergence, a zone approximately 32 to 48 km (20 to 30 mi) wide varying in latitude seasonally.[4] The region covers some 20 percent of the Southern Hemisphere, of which 5.5 percent (14 million km2) is the surface area of the Antarctic continent itself. All of the land and ice shelves south of 60°S latitude are administered under the Antarctic Treaty System. Biogeographically, the Antarctic ecozone is one of eight ecozones of the Earth's land surface.
  • Antoine Lavoisier
    was a French nobleman and chemist who was central to the 18th-century chemical revolution and who had a large influence on both the history of chemistry and the history of biology.[5] He is widely considered in popular literature as the "father of modern chemistry".[6][7] It is generally accepted that Lavoisier's great accomplishments in chemistry stem largely from his changing the science from a qualitative to a quantitative one. Lavoisier is most noted for his discovery of the role oxygen plays in combustion. He recognized and named oxygen (1778) and hydrogen (1783), and opposed the phlogiston theory. Lavoisier helped construct the metric system, wrote the first extensive list of elements, and helped to reform chemical nomenclature. He predicted the existence of silicon (1787)[8] and was also the first to establish that sulfur was an element (1777) rather than a compound.[9] He discovered that, although matter may change its form or shape, its mass always remains the same. Lavoisier was a powerful member of a number of aristocratic councils and an administrator of the Ferme générale. The Ferme générale was one of the most hated components of the Ancien Régime because of the profits it took at the expense of the state, the secrecy of the terms of its contracts, and the violence of its armed agents.[10] All of these political and economic activities enabled him to fund his scientific research. At the height of the French Revolution, he was charged with tax fraud and selling adulterated tobacco, and was guillotined.
  • Arctic
    is a polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Alaska (United States), Finland, Greenland (Denmark), Iceland, Northern Canada, Norway, Russia and Sweden. Land within the Arctic region has seasonally varying snow and ice cover, with predominantly treeless permafrost (permanently frozen underground ice) containing tundra. Arctic seas contain seasonal sea ice in many places. The Arctic region is a unique area among Earth's ecosystems. The cultures in the region and the Arctic indigenous peoples have adapted to its cold and extreme conditions. Life in the Arctic includes zooplankton and phytoplankton, fish and marine mammals, birds, land animals, plants and human societies.[3] Arctic land is bordered by the subarctic.
  • b
  • Best Management Practices
    are methods that have been determined to be the most effective and practical means of preventing or reducing non-point source pollution to help achieve water quality goals. BMPS include both measures to prevent pollution and measures to mitigate the pollution of the environment.
  • BMP
    are methods that have been determined to be the most effective and practical means of preventing or reducing non-point source pollution to help achieve water quality goals. BMPS include both measures to prevent pollution and measures to mitigate the pollution of the environment.
  • BMPS
    are methods that have been determined to be the most effective and practical means of preventing or reducing non-point source pollution to help achieve water quality goals. BMPS include both measures to prevent pollution and measures to mitigate the pollution of the environment.
  • c
  • Capacity Limited Reach
    In general river hydraulics, a river is said to carry two things; water and sediments. The ratio of one to the other affects many things from physical and chemical properties to the river's morphology, and the last one is the most important. Sediments in rivers are constantly in motion, so scour and deposition are always happening but balancing each other. Most rivers in the Caribbean are supply limited. The only Caribbean island that has capacity limited rivers is Haiti. The high population of goats in Haiti eats virtually all of the erosion-resistant land cover and that is the reason that we can only observe Caribbean trench rivers only on this island.A river is said to be capacity limited if the channel does not provide enough space and clearance to properly deliver its sediments to the recipient body of water. 
  • climate engineers
    are a new breed of engineers trying to solve today's climate and global warming-related issues like carbon sequestration and other radical experiments all in a joint effort to fight climate change trends. There are a few University programs rolling out, but they have found increasing criticism and opposition by environmentalists organizations and movements that question their radical methods, as they fear that the solutions could be worse than the problem at hand. There are divided and mixed opinions regarding this topic, but time is something that we do not have for bureaucratic debates and desperate times call for desperate measures.
  • Coal
    is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements; chiefly hydrogen, sulfur, oxygen, and nitrogen.[1] Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years.[2] Vast deposits of coal originates in former wetlands—called coal forests—that covered much of the Earth's tropical land areas during the late Carboniferous (Pennsylvanian) and Permian times.[3][4] As a fossil fuel burned for heat, coal supplies about a quarter of the world's primary energy and two-fifths of its electricity.[5] Some iron and steel making and other industrial processes burn coal. The extraction and use of coal causes many premature deaths and much illness.[6] Coal industry damages the environment, including by climate change as it is the largest anthropogenic source of carbon dioxide, 14 Gt in 2016,[7] which is 40% of the total fossil fuel emissions.[8] As part of the worldwide energy transition many countries have stopped using or use less coal, and the UN Secretary General has asked governments to stop building new coal plants by 2020.[9] The largest consumer and importer of coal is China. China mines almost half the world's coal, followed by India with about a tenth. Australia accounts for about a third of world coal exports followed by Indonesia and Russia.[10]
  • conservation of energy
    is a version of the law of conservation of energy, adapted for thermodynamic processes, distinguishing two kinds of transfer of energy, as heat and as thermodynamic work, and relating them to a function of a body's state, called Internal energy. The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another but can be neither created nor destroyed. For a thermodynamic process without transfer of matter, the first law is often formulated[1][nb 1] {\displaystyle \Delta U=Q-W}, where ΔU denotes the change in the internal energy of a closed system, Q denotes the quantity of energy supplied to the system as heat, and W denotes the amount of thermodynamic work done by the system on its surroundings. An equivalent statement is that perpetual motion machines of the first kind are impossible. For processes that include transfer of matter, a further statement is needed: 'With due account of the respective reference states of the systems, when two systems, which may be of different chemical compositions, initially separated only by an impermeable wall, and otherwise isolated, are combined into a new system by the thermodynamic operation of removal of the wall, then {\displaystyle U_{0}=U_{1}+U_{2}}, where U0 denotes the internal energy of the combined system, and U1 and U2 denote the internal energies of the respective separated systems.'
  • d
  • dogmatic
    is an official system of principles or doctrines of a religion, such as Roman Catholicism,[1] or the positions of a philosopher or of a philosophical school such as Stoicism. In the pejorative sense, dogma refers to enforced decisions, such as those of aggressive political interests or authorities.[2][3] More generally, it is applied to some strong belief whose adherents are not willing to discuss it rationally. This attitude is named as a dogmatic one, or as dogmatism; and is often used to refer to matters related to religion, but is not limited to theistic attitudes alone and is often used with respect to political or philosophical dogmas.
  • f
  • First Law of Thermodynamics
    is a version of the law of conservation of energy, adapted for thermodynamic processes, distinguishing two kinds of transfer of energy, as heat and as thermodynamic work, and relating them to a function of a body's state, called Internal energy. The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another but can be neither created nor destroyed. For a thermodynamic process without transfer of matter, the first law is often formulated[1][nb 1] {\displaystyle \Delta U=Q-W}, where ΔU denotes the change in the internal energy of a closed system, Q denotes the quantity of energy supplied to the system as heat, and W denotes the amount of thermodynamic work done by the system on its surroundings. An equivalent statement is that perpetual motion machines of the first kind are impossible. For processes that include transfer of matter, a further statement is needed: 'With due account of the respective reference states of the systems, when two systems, which may be of different chemical compositions, initially separated only by an impermeable wall, and otherwise isolated, are combined into a new system by the thermodynamic operation of removal of the wall, then {\displaystyle U_{0}=U_{1}+U_{2}}, where U0 denotes the internal energy of the combined system, and U1 and U2 denote the internal energies of the respective separated systems.'
  • Fluvial morphology
    a term associated with studies of the changes in shape and form of water bodies in a much shorter span than geological changes, typically ranging to around 10 years.
  • fossil gas
    is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxide, nitrogen, hydrogen sulfide, or helium.[2] It is formed when layers of decomposing plant and animal matter are exposed to intense heat and pressure under the surface of the Earth over millions of years. The energy that the plants originally obtained from the sun is stored in the form of chemical bonds in the gas.[3] Natural gas is a non-renewable[3] hydrocarbon used as a source of energy for heating, cooking, and electricity generation. It is also used as a fuel for vehicles and as a chemical feedstock in the manufacture of plastics and other commercially important organic chemicals. Natural gas has a complicated effect on climate change; it itself is a greenhouse gas,[4] and it releases carbon dioxide when burned. However, natural gas use often supplants coal use, which is far more environmentally damaging, leading to lower net carbon dioxide emissions in countries such as the US.[5][6][7] Natural gas is found in deep underground rock formations or associated with other hydrocarbon reservoirs in coal beds and as methane clathrates. Petroleum is another resource and fossil fuel found close to and with natural gas. Most natural gas was created over time by two mechanisms: biogenic and thermogenic. Biogenic gas is created by methanogenic organisms in marshes, bogs, landfills, and shallow sediments. Deeper in the earth, at greater temperature and pressure, thermogenic gas is created from buried organic material.[8][9] In petroleum production, gas is sometimes burned as flare gas. Before natural gas can be used as a fuel, most, but not all, must be processed to remove impurities, including water, to meet the specifications of marketable natural gas. The by-products of this processing include: ethane, propane, butanes, pentanes, and higher molecular weight hydrocarbons, hydrogen sulfide (which may be converted into pure sulfur), carbon dioxide, water vapor, and sometimes helium and nitrogen. Natural gas is sometimes informally referred to simply as "gas", especially when compared to other energy sources such as oil or coal. However, it is not to be confused with gasoline, especially in North America, where the term gasoline is often shortened in colloquial usage to gas.
  • fracking
    is a well stimulation technique in which rock is fractured by a pressurized liquid. The process involves the high-pressure injection of 'fracking fluid' (primarily water, containing sand or other proppants suspended with the aid of thickening agents) into a wellbore to create cracks in the deep-rock formations through which natural gas, petroleum, and brine will flow more freely. When the hydraulic pressure is removed from the well, small grains of hydraulic fracturing proppants (either sand or aluminium oxide) hold the fractures open.[1] Hydraulic fracturing began as an experiment in 1947, and the first commercially successful application followed in 1950. As of 2012, 2.5 million "frac jobs" had been performed worldwide on oil and gas wells; over one million of those within the U.S.[2][3] Such treatment is generally necessary to achieve adequate flow rates in shale gas, tight gas, tight oil, and coal seam gas wells.[4] Some hydraulic fractures can form naturally in certain veins or dikes.[5] Drilling and hydraulic fracturing have made the United States a major crude oil exporter as of 2019,[6] while helping reduce greenhouse gas emissions.[7] Improvements in the national economy and better prices for consumers have been a result of the decade-long fracking boom.[8] Hydraulic fracturing is highly controversial. Its proponents advocate the economic benefits of more extensively accessible hydrocarbons,[9][10] as well as replacing coal with natural gas, which burns cleaner and emits half as much carbon dioxide (CO2).[11][12] Opponents of fracking argue that these are outweighed by the potential environmental impacts, which include risks of ground water and surface water contamination, noise and air pollution, and the triggering of earthquakes, along with the resulting hazards to public health and the environment.[13][14] Research has determined that human health is affected.[15][16] Groundwater contamination has been documented.[17] Adherence to regulation and safety procedures is required to avoid further negative impacts.[18] Methane leakage is also a problem directly associated with hydraulic fracturing, as an Environmental Defense Fund (EDF) report in the US highlights, where the leakage rate in Pennsylvania during extensive testing and analysis was found to be approximately 10%, or over five times the reported figures.[19] This leakage rate is considered representative of the hydraulic fracturing industry in the US generally. The EDF has recently announced a satellite mission to further locate and measure methane emissions.[20] Increases in seismic activity following hydraulic fracturing along dormant or previously unknown faults are sometimes caused by the deep-injection disposal of hydraulic fracturing flow back (a byproduct of hydraulically fractured wells),[21] and produced formation brine (a byproduct of both fractured and nonfractured oil and gas wells).[22] For these reasons, hydraulic fracturing is under international scrutiny, restricted in some countries, and banned altogether in others.[23][24][25] The European Union is drafting regulations that would permit the controlled application of hydraulic fracturing.[26]
  • g
  • Geo-Engineering
    are a new breed of engineers trying to solve today's climate and global warming-related issues like carbon sequestration and other radical experiments all in a joint effort to fight climate change trends. There are a few University programs rolling out, but they have found increasing criticism and opposition by environmentalists organizations and movements that question their radical methods, as they fear that the solutions could be worse than the problem at hand. There are divided and mixed opinions regarding this topic, but time is something that we do not have for bureaucratic debates and desperate times call for desperate measures.
  • geology
    is an earth science concerned with the solid Earth, the rocks of which it is composed, and the processes by which they change over time. Geology can also include the study of the solid features of any terrestrial planet or natural satellite such as Mars or the Moon. Modern geology significantly overlaps all other earth sciences, including hydrology and the atmospheric sciences, and so is treated as one major aspect of integrated earth system science and planetary science. Aerial view of Grand Prismatic Spring; Hot Springs, Midway & Lower Geyser Basin, Yellowstone National Park Kinney Lake and Mount Whitehorn near Mount Robson, Canada Geology describes the structure of the Earth on and beneath its surface, and the processes that have shaped that structure. It also provides tools to determine the relative and absolute ages of rocks found in a given location, and also to describe the histories of those rocks.[3] By combining these tools, geologists are able to chronicle the geological history of the Earth as a whole, and also to demonstrate the age of the Earth. Geology provides the primary evidence for plate tectonics, the evolutionary history of life, and the Earth's past climates. Geologists use a wide variety of methods to understand the Earth's structure and evolution, including field work, rock description, geophysical techniques, chemical analysis, physical experiments, and numerical modelling. In practical terms, geology is important for mineral and hydrocarbon exploration and exploitation, evaluating water resources, understanding of natural hazards, the remediation of environmental problems, and providing insights into past climate change. Geology is a major academic discipline, and it plays an important role in geotechnical engineering.
  • Geomorphology
    a term associated with studies of the changes in shape and form of water bodies in a much shorter span than geological changes, typically ranging to around 10 years.
  • Global Warming
    is the long-term rise in the average temperature of the Earth's climate system. It is a major aspect of climate change and has been demonstrated by direct temperature measurements and by measurements of various effects of warming.[1][2] Global warming and climate change are often used interchangeably.[3] But more accurately, global warming is the mainly human-caused increase in global surface temperatures and its projected continuation,[4] while climate change includes both global warming and its effects, such as changes in precipitation.[5] While there have been prehistoric periods of global warming,[6] many observed changes since the mid-20th century have been unprecedented over decades to millennia.
  • greenhose effect
    is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without this atmosphere.[1][2] Radiatively active gases (i.e., greenhouse gases) in a planet's atmosphere radiate energy in all directions. Part of this radiation is directed towards the surface, warming it.[3] The intensity of the downward radiation – that is, the strength of the greenhouse effect – will depend on the atmosphere's temperature and on the amount of greenhouse gases that the atmosphere contains. Earth’s natural greenhouse effect is critical to supporting life, and initially was a precursor to life moving out of the ocean onto land. Human activities, however, mainly the burning of fossil fuels and clearcutting of forests, have accelerated the greenhouse effect and caused global warming.[4] The planet Venus experienced runaway greenhouse effect, resulting in an atmosphere which is 96% carbon dioxide, with surface atmospheric pressure roughly the same as found 900 m (3,000 ft) underwater on Earth. Venus may have had water oceans, but they would have boiled off as the mean surface temperature rose to 735 K (462 °C; 863 °F).[5][6][7] The term "greenhouse effect" continues to see use in scientific circles and the media despite being a slight misnomer, as an atmosphere reduces radiative heat loss[8] while a greenhouse blocks convective heat loss.[2] The result, however, is an increase in temperature in both cases.[9][10]
  • greenland
    is the world's largest island,[d] located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. It is an autonomous territory[10] within the Kingdom of Denmark. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe (specifically Norway and Denmark, the colonial powers, as well as the nearby island of Iceland) for more than a millennium.[11] The majority of its residents are Inuit, whose ancestors migrated from Alaska through Northern Canada, gradually settling across the island by the 13th century.[12] Nowadays the population is largely concentrated on the southwest coast of the island while the rest of the island is sparsely populated. Greenland is divided into five municipalities — Sermersooq, Kujalleq, Qeqertalik, Qeqqata, and Avannaata. It has two unincorporated areas — the Northeast Greenland National Park and the Thule Air Base. The last one, even if under Danish control, is administered by the United States Air Force.[13]
  • h
  • heat capacity
    is a physical property of matter, defined as the amount of heat to be supplied to a given mass of a material to produce a unit change in its temperature.[1] The SI unit of heat capacity is joule per kelvin (J/K). Heat capacity is an extensive property. The corresponding intensive property is the specific heat capacity. Dividing the heat capacity by the amount of substance in moles yields its molar heat capacity. The volumetric heat capacity measures the heat capacity per volume. Heat capacity is often said as thermal mass in architecture and civil engineering to refer to the heat capacity of a building .
  • hieroglyphs
    was a character of the ancient Egyptian writing system. Logographic scripts that are pictographic in form in a way reminiscent of ancient Egyptian are also sometimes called "hieroglyphs".[1] In Neoplatonism, especially during the Renaissance, a "hieroglyph" was an artistic representation of an esoteric idea, which Neoplatonists believed actual Egyptian hieroglyphs to be. The word hieroglyphics refer to a hieroglyphic script. The Egyptians invented the pictorial script. The appearance of these distinctive figures in 3000 BCE marked the beginning of Egyptian civilization. Though based on images, Egyptian script was more than a sophisticated form of picture-writing. Each picture/glyph served three functions: (1) to represent the image of a thing or action, (2) to stand for the sound of a syllable, and (3) to clarify the precise meaning of adjoining glyphs. Writing hieroglyphs required some artistic skill, limiting the number chosen to learn it.[2] Only those privileged with an extensive education (i.e. the Pharaoh, nobility and priests) were able to read and write hieroglyphs; others used simpler 'joined-up' versions: demotic and hieratic script.
  • hydraulic fracturing
    is a well stimulation technique in which rock is fractured by a pressurized liquid. The process involves the high-pressure injection of 'fracking fluid' (primarily water, containing sand or other proppants suspended with the aid of thickening agents) into a wellbore to create cracks in the deep-rock formations through which natural gas, petroleum, and brine will flow more freely. When the hydraulic pressure is removed from the well, small grains of hydraulic fracturing proppants (either sand or aluminium oxide) hold the fractures open.[1] Hydraulic fracturing began as an experiment in 1947, and the first commercially successful application followed in 1950. As of 2012, 2.5 million "frac jobs" had been performed worldwide on oil and gas wells; over one million of those within the U.S.[2][3] Such treatment is generally necessary to achieve adequate flow rates in shale gas, tight gas, tight oil, and coal seam gas wells.[4] Some hydraulic fractures can form naturally in certain veins or dikes.[5] Drilling and hydraulic fracturing have made the United States a major crude oil exporter as of 2019,[6] while helping reduce greenhouse gas emissions.[7] Improvements in the national economy and better prices for consumers have been a result of the decade-long fracking boom.[8] Hydraulic fracturing is highly controversial. Its proponents advocate the economic benefits of more extensively accessible hydrocarbons,[9][10] as well as replacing coal with natural gas, which burns cleaner and emits half as much carbon dioxide (CO2).[11][12] Opponents of fracking argue that these are outweighed by the potential environmental impacts, which include risks of ground water and surface water contamination, noise and air pollution, and the triggering of earthquakes, along with the resulting hazards to public health and the environment.[13][14] Research has determined that human health is affected.[15][16] Groundwater contamination has been documented.[17] Adherence to regulation and safety procedures is required to avoid further negative impacts.[18] Methane leakage is also a problem directly associated with hydraulic fracturing, as an Environmental Defense Fund (EDF) report in the US highlights, where the leakage rate in Pennsylvania during extensive testing and analysis was found to be approximately 10%, or over five times the reported figures.[19] This leakage rate is considered representative of the hydraulic fracturing industry in the US generally. The EDF has recently announced a satellite mission to further locate and measure methane emissions.[20] Increases in seismic activity following hydraulic fracturing along dormant or previously unknown faults are sometimes caused by the deep-injection disposal of hydraulic fracturing flow back (a byproduct of hydraulically fractured wells),[21] and produced formation brine (a byproduct of both fractured and nonfractured oil and gas wells).[22] For these reasons, hydraulic fracturing is under international scrutiny, restricted in some countries, and banned altogether in others.[23][24][25] The European Union is drafting regulations that would permit the controlled application of hydraulic fracturing.[26]
  • i
  • ice age
    is a long period of reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and greenhouse periods, during which there are no glaciers on the planet. Earth is currently in the Quaternary glaciation, known in popular terminology as the Ice Age.[1] Individual pulses of cold climate within an ice age are termed "glacial periods" (or, alternatively, "glacials", "glaciations", "glacial stages", "stadials", "stades", or colloquially, "ice ages"), and intermittent warm periods within an ice age are called "interglacials" or "interstadials", with both climatic pulses part of the Quaternary or other periods in Earth's history.[2] In the terminology of glaciology, ice age implies the presence of extensive ice sheets in both northern and southern hemispheres.[3] By this definition, we are in an interglacial period—the Holocene. The amount of heat trapping gases emitted into Earth's oceans and atmosphere are predicted to prevent the next glacial period, which otherwise would begin in around 50,000 years, and likely more glacial cycles.[4][5]
  • 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. Textiles were the dominant industry of the Industrial Revolution in terms of employment, value of output and capital invested. The textile industry was also the first to use modern production methods.[1]:40 The Industrial Revolution began in Great Britain, and many of the technological innovations were of British origin.[2][3] By the mid-18th century Britain was the world's leading commercial nation,[4] controlling a global trading empire with colonies in North America and the Caribbean, and with major military and political hegemony on the Indian subcontinent, particularly with the proto-industrialised Mughal Bengal, through the activities of the East India Company.[5][6][7][8] The development of trade and the rise of business were among the major causes of the Industrial Revolution.[1]:15 The Industrial Revolution marks a major turning point in history; almost every aspect of daily life was influenced in some way. In particular, average income and population began to exhibit unprecedented sustained growth. Some economists say that the major effect of the Industrial Revolution was that the standard of living for the general population in the western world began to increase consistently for the first time in history, although others have said that it did not begin to meaningfully improve until the late 19th and 20th centuries.[9][10][11] GDP per capita was broadly stable before the Industrial Revolution and the emergence of the modern capitalist economy,[12] while the Industrial Revolution began an era of per-capita economic growth in capitalist economies.[13] Economic historians are in agreement that the onset of the Industrial Revolution is the most important event in the history of humanity since the domestication of animals and plants.[14] Although the structural change from agriculture to industry is widely associated with the Industrial Revolution, in the United Kingdom it was already almost complete by 1760.[15] The precise start and end of the Industrial Revolution is still debated among historians, as is the pace of economic and social changes.[16][17][18][19] Eric Hobsbawm held that the Industrial Revolution began in Britain in the 1780s and was not fully felt until the 1830s or 1840s,[16] while T. S. Ashton held that it occurred roughly between 1760 and 1830.[17] Rapid industrialization first began in Britain, starting with mechanized spinning in the 1780s,[20] with high rates of growth in steam power and iron production occurring after 1800. Mechanized textile production spread from Great Britain to continental Europe and the United States in the early 19th century, with important centres of textiles, iron and coal emerging in Belgium and the United States and later textiles in France.[1] An economic recession occurred from the late 1830s to the early 1840s when the adoption of the original innovations of the Industrial Revolution, such as mechanized spinning and weaving, slowed and their markets matured. Innovations developed late in the period, such as the increasing adoption of locomotives, steamboats and steamships, hot blast iron smelting and new technologies, such as the electrical telegraph, widely introduced in the 1840s and 1850s, were not powerful enough to drive high rates of growth. Rapid economic growth began to occur after 1870, springing from a new group of innovations in what has been called the Second Industrial Revolution. These new innovations included new steel making processes, mass-production, assembly lines, electrical grid systems, the large-scale manufacture of machine tools and the use of increasingly advanced machinery in steam-powered factories.[1][21][22][23]
  • Intergovernmental Panel on Climate Change
    The Intergovernmental Panel on Climate Change (IPCC) is an intergovernmental body of the United Nations[1][2] that is dedicated to providing the world with objective, scientific information relevant to understanding the scientific basis of the risk of human-induced[3] climate change, its natural, political, and economic impacts and risks, and possible response options.[4] The IPCC was established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) and was later endorsed by the United Nations General Assembly. Membership is open to all members of the WMO and UN.[5] The IPCC produces reports that contribute to the work of the United Nations Framework Convention on Climate Change (UNFCCC), the main international treaty on climate change.[6][7] The objective of the UNFCCC is to "stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic (human-induced) interference with the climate system".[6] The IPCC's Fifth Assessment Report was a critical scientific input into the UNFCCC's Paris Agreement in 2015.[8] IPCC reports cover the "scientific, technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation."[7] The IPCC does not carry out original research, nor does it monitor climate or related phenomena itself. Rather, it assesses published literature, including peer-reviewed and non-peer-reviewed sources.[9] However, the IPCC can be said to stimulate research in climate science. Chapters of IPCC reports often close with sections on limitations and knowledge or research gaps, and the announcement of an IPCC special report can catalyse research activity in that area. Thousands of scientists and other experts contribute on a voluntary basis[10] to writing and reviewing reports, which are then reviewed by governments. IPCC reports contain a "Summary for Policymakers", which is subject to line-by-line approval by delegates from all participating governments. Typically, this involves the governments of more than 120 countries.[11] The IPCC provides an internationally accepted authority on climate change,[12] producing reports that have the agreement of leading climate scientists and consensus from participating governments. The 2007 Nobel Peace Prize was shared between the IPCC and Al Gore.[13] Following the election of a new Bureau in 2015, the IPCC embarked on its sixth assessment cycle. Besides the Sixth Assessment Report, to be completed in 2022, the IPCC released the Special Report on Global Warming of 1.5 °C in October 2018, released an update to its 2006 Guidelines for National Greenhouse Gas Inventories—the 2019 Refinement—in May 2019, and delivered two further special reports in 2019: the Special Report on Climate Change and Land (SRCCL), published online on 7 August, and the Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC), released on 25 September 2019. This makes the sixth assessment cycle the most ambitious in the IPCC's 30-year history.[14] The IPCC also decided to prepare a special report on cities and climate change in the seventh assessment cycle and held a conference in March 2018 to stimulate research in this area.
  • IPCC
    The Intergovernmental Panel on Climate Change (IPCC) is an intergovernmental body of the United Nations[1][2] that is dedicated to providing the world with objective, scientific information relevant to understanding the scientific basis of the risk of human-induced[3] climate change, its natural, political, and economic impacts and risks, and possible response options.[4] The IPCC was established in 1988 by the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) and was later endorsed by the United Nations General Assembly. Membership is open to all members of the WMO and UN.[5] The IPCC produces reports that contribute to the work of the United Nations Framework Convention on Climate Change (UNFCCC), the main international treaty on climate change.[6][7] The objective of the UNFCCC is to "stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic (human-induced) interference with the climate system".[6] The IPCC's Fifth Assessment Report was a critical scientific input into the UNFCCC's Paris Agreement in 2015.[8] IPCC reports cover the "scientific, technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation."[7] The IPCC does not carry out original research, nor does it monitor climate or related phenomena itself. Rather, it assesses published literature, including peer-reviewed and non-peer-reviewed sources.[9] However, the IPCC can be said to stimulate research in climate science. Chapters of IPCC reports often close with sections on limitations and knowledge or research gaps, and the announcement of an IPCC special report can catalyse research activity in that area. Thousands of scientists and other experts contribute on a voluntary basis[10] to writing and reviewing reports, which are then reviewed by governments. IPCC reports contain a "Summary for Policymakers", which is subject to line-by-line approval by delegates from all participating governments. Typically, this involves the governments of more than 120 countries.[11] The IPCC provides an internationally accepted authority on climate change,[12] producing reports that have the agreement of leading climate scientists and consensus from participating governments. The 2007 Nobel Peace Prize was shared between the IPCC and Al Gore.[13] Following the election of a new Bureau in 2015, the IPCC embarked on its sixth assessment cycle. Besides the Sixth Assessment Report, to be completed in 2022, the IPCC released the Special Report on Global Warming of 1.5 °C in October 2018, released an update to its 2006 Guidelines for National Greenhouse Gas Inventories—the 2019 Refinement—in May 2019, and delivered two further special reports in 2019: the Special Report on Climate Change and Land (SRCCL), published online on 7 August, and the Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC), released on 25 September 2019. This makes the sixth assessment cycle the most ambitious in the IPCC's 30-year history.[14] The IPCC also decided to prepare a special report on cities and climate change in the seventh assessment cycle and held a conference in March 2018 to stimulate research in this area.
  • l
  • LIDS
    are new trends in water resources engineering that try to mimic the predevelopment conditions and the natural hydrologic cycle, they include mitigation techniques such as; green roofs, bio-swales, roof disconnections, bio-retention, rain gardens, rain harvesting among other variants and combinations thereof.
  • Low Impact Developments
    are new trends in water resources engineering that try to mimic the predevelopment conditions and the natural hydrologic cycle, they include mitigation techniques such as; green roofs, bio-swales, roof disconnections, bio-retention, rain gardens, rain harvesting among other variants and combinations thereof.
  • m
  • middle paleolithic
    is the second subdivision of the Paleolithic or Old Stone Age as it is understood in Europe, Africa and Asia. The term Middle Stone Age is used as an equivalent or a synonym for the Middle Paleolithic in African archeology.[1] The Middle Paleolithic broadly spanned from 300,000 to 30,000 years ago. There are considerable dating differences between regions. The Middle Paleolithic was succeeded by the Upper Paleolithic subdivision which first began between 50,000 and 40,000 years ago.[1] Pettit and White date the Early Middle Paleolithic in Great Britain to about 325,000 to 180,000 years ago (late Marine Isotope Stage 9 to late Marine Isotope Stage 7), and the Late Middle Paleolithic as about 60,000 to 35,000 years ago.[2] According to the theory of the recent African origin of modern humans, anatomically modern humans began migrating out of Africa during the Middle Stone Age/Middle Paleolithic around 100,000 or 70,000 years ago and began to replace earlier pre-existent Homo species such as the Neanderthals and Homo erectus.[3] However, recent discoveries of fossils originating from Israel indicate that our species (Homo sapiens) lived outside of Africa 185,000 years ago; some 85,000 years earlier than previous evidence suggests. [4]
  • Milankovitch cycles
    describe the collective effects of changes in the Earth's movements on its climate over thousands of years. The term is named for Serbian geophysicist and astronomer Milutin Milanković. In the 1920s, he hypothesized that variations in eccentricity, axial tilt, and precession resulted in cyclical variation in the solar radiation reaching the Earth and that this orbital forcing strongly influenced climatic patterns on Earth.
  • n
  • narcissist
    is the pursuit of gratification from vanity or egotistic admiration of one's idealised self image and attributes. This includes self-flattery, perfectionism, and arrogance.[1] The term originated from Greek mythology, where the young Narcissus fell in love with his own image reflected in a pool of water. Narcissism is a concept in psychoanalytic theory, which was popularly introduced in Sigmund Freud's essay On Narcissism (1914). The American Psychiatric Association has listed the classification narcissistic personality disorder in its Diagnostic and Statistical Manual of Mental Disorders (DSM) since 1968, drawing on the historical concept of megalomania. Narcissism is also considered a social or cultural problem. It is a factor in trait theory used in various self-report inventories of personality such as the Millon Clinical Multiaxial Inventory. It is one of the three dark triadic personality traits (the others being psychopathy and Machiavellianism). Except in the sense of primary narcissism or healthy self-love, narcissism is usually considered a problem in a person's or group's relationships with self and others. Narcissism is not the same as egocentrism or egoism.
  • natural gas
    is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxide, nitrogen, hydrogen sulfide, or helium.[2] It is formed when layers of decomposing plant and animal matter are exposed to intense heat and pressure under the surface of the Earth over millions of years. The energy that the plants originally obtained from the sun is stored in the form of chemical bonds in the gas.[3] Natural gas is a non-renewable[3] hydrocarbon used as a source of energy for heating, cooking, and electricity generation. It is also used as a fuel for vehicles and as a chemical feedstock in the manufacture of plastics and other commercially important organic chemicals. Natural gas has a complicated effect on climate change; it itself is a greenhouse gas,[4] and it releases carbon dioxide when burned. However, natural gas use often supplants coal use, which is far more environmentally damaging, leading to lower net carbon dioxide emissions in countries such as the US.[5][6][7] Natural gas is found in deep underground rock formations or associated with other hydrocarbon reservoirs in coal beds and as methane clathrates. Petroleum is another resource and fossil fuel found close to and with natural gas. Most natural gas was created over time by two mechanisms: biogenic and thermogenic. Biogenic gas is created by methanogenic organisms in marshes, bogs, landfills, and shallow sediments. Deeper in the earth, at greater temperature and pressure, thermogenic gas is created from buried organic material.[8][9] In petroleum production, gas is sometimes burned as flare gas. Before natural gas can be used as a fuel, most, but not all, must be processed to remove impurities, including water, to meet the specifications of marketable natural gas. The by-products of this processing include: ethane, propane, butanes, pentanes, and higher molecular weight hydrocarbons, hydrogen sulfide (which may be converted into pure sulfur), carbon dioxide, water vapor, and sometimes helium and nitrogen. Natural gas is sometimes informally referred to simply as "gas", especially when compared to other energy sources such as oil or coal. However, it is not to be confused with gasoline, especially in North America, where the term gasoline is often shortened in colloquial usage to gas.
  • o
  • OIL
    is a naturally occuring, yellowish-black liquid found in geological formations beneath the Earth's surface. It is commonly refined into various types of fuels. Components of petroleum are separated using a technique called fractional distillation, i.e. separation of a liquid mixture into fractions differing in boiling point by means of distillation, typically using a fractionating column. It consists of naturally occurring hydrocarbons of various molecular weights and may contain miscellaneous organic compounds.[1] The name petroleum covers both naturally occurring unprocessed crude oil and petroleum products that are made up of refined crude oil. A fossil fuel, petroleum is formed when large quantities of dead organisms, mostly zooplankton and algae, are buried underneath sedimentary rock and subjected to both intense heat and pressure. Petroleum has mostly been recovered by oil drilling (natural petroleum springs are rare). Drilling is carried out after studies of structural geology (at the reservoir scale), sedimentary basin analysis, and reservoir characterisation (mainly in terms of the porosity and permeability of geologic reservoir structures) have been completed.[2][3] It is refined and separated, most easily by distillation, into numerous consumer products, from gasoline (petrol) and kerosene to asphalt and chemical reagents used to make plastics, pesticides and pharmaceuticals.[4] Petroleum is used in manufacturing a wide variety of materials,[5] and it is estimated that the world consumes about 95 million barrels each day. The use of petroleum as fuel causes global warming and ocean acidification. According to the UN's Intergovernmental Panel on Climate Change, without fossil fuel phase-out, including petroleum, there will be "severe, pervasive, and irreversible impacts for people and ecosystems".[6]
  • oxidation
    pronunciation: /ˈrɛdɒks/ redoks or /ˈriːdɒks/ reedoks[1]) is a type of chemical reaction in which the oxidation states of atoms are changed. Redox reactions are characterized by the transfer of electrons between chemical species, most often with one species (the reducing agent) undergoing oxidation (losing electrons) while another species (the oxidizing agent) undergoes reduction (gains electrons).[2] The chemical species from which the electron is stripped is said to have been oxidized, while the chemical species to which the electron is added is said to have been reduced. In other words: Oxidation is the loss of electrons or an increase in the oxidation state of an atom by another atom, an ion, or a molecule. Reduction is the gain of electrons or a decrease in the oxidation state of an atom by another atom, an ion, or a molecule. For example, during the combustion of wood, electrons are transferred from carbon atoms in the wood to oxygen atoms in the air. The oxygen atoms undergo reduction, gaining electrons, while the carbon atoms undergo oxidation, losing electrons. Thus oxygen is the oxidizing agent and carbon is the reducing agent in this reaction.[3] Although oxidation reactions are commonly associated with the formation of oxides from oxygen molecules, oxygen is not necessarily included in such reactions, as other chemical species can serve the same function.[3] Redox reactions can occur relatively slowly, as in the formation of rust, or much more rapidly, as in the case of burning fuel. There are simple redox processes, such as the oxidation of carbon to yield carbon dioxide (CO2) or the reduction of carbon by hydrogen to yield methane (CH4), and more complex processes such as the oxidation of glucose (C6H12O6) in the human body.
  • p
  • paleoclimate
    is the study of climates for which direct measurements were not taken.[1] As instrumental records only span a tiny part of Earth history, the reconstruction of ancient climate is important to understand natural variation and the evolution of the current climate. Paleoclimatology uses a variety of proxy methods from the Earth and life sciences to obtain data previously preserved within rocks, sediments, boreholes, ice sheets, tree rings, corals, shells, and microfossils. Combined with techniques to date the proxies, these paleoclimate records are used to determine the past states of Earth's atmosphere. The scientific field of paleoclimatology came to maturity in the 20th century. Notable periods studied by paleoclimatologists are the frequent glaciations the Earth has undergone, rapid cooling events such as the Younger Dryas, and the fast rate of warming during the Paleocene–Eocene Thermal Maximum. Studies of past changes in the environment and biodiversity often reflect on the current situation, specifically the impact of climate on mass extinctions and biotic recovery and current global warming.[2][3]
  • Petroleum
    is a naturally occuring, yellowish-black liquid found in geological formations beneath the Earth's surface. It is commonly refined into various types of fuels. Components of petroleum are separated using a technique called fractional distillation, i.e. separation of a liquid mixture into fractions differing in boiling point by means of distillation, typically using a fractionating column. It consists of naturally occurring hydrocarbons of various molecular weights and may contain miscellaneous organic compounds.[1] The name petroleum covers both naturally occurring unprocessed crude oil and petroleum products that are made up of refined crude oil. A fossil fuel, petroleum is formed when large quantities of dead organisms, mostly zooplankton and algae, are buried underneath sedimentary rock and subjected to both intense heat and pressure. Petroleum has mostly been recovered by oil drilling (natural petroleum springs are rare). Drilling is carried out after studies of structural geology (at the reservoir scale), sedimentary basin analysis, and reservoir characterisation (mainly in terms of the porosity and permeability of geologic reservoir structures) have been completed.[2][3] It is refined and separated, most easily by distillation, into numerous consumer products, from gasoline (petrol) and kerosene to asphalt and chemical reagents used to make plastics, pesticides and pharmaceuticals.[4] Petroleum is used in manufacturing a wide variety of materials,[5] and it is estimated that the world consumes about 95 million barrels each day. The use of petroleum as fuel causes global warming and ocean acidification. According to the UN's Intergovernmental Panel on Climate Change, without fossil fuel phase-out, including petroleum, there will be "severe, pervasive, and irreversible impacts for people and ecosystems".[6]
  • photosynthesis
    is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organisms' activities. This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water – hence the name photosynthesis, from the Greek φῶς, phōs, "light", and σύνθεσις, synthesis, "putting together".[1][2][3] In most cases, oxygen is also released as a waste product. Most plants, most algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies all of the organic compounds and most of the energy necessary for life on Earth.[4] Although photosynthesis is performed differently by different species, the process always begins when energy from light is absorbed by proteins called reaction centres that contain green chlorophyll pigments. In plants, these proteins are held inside organelles called chloroplasts, which are most abundant in leaf cells, while in bacteria they are embedded in the plasma membrane. In these light-dependent reactions, some energy is used to strip electrons from suitable substances, such as water, producing oxygen gas. The hydrogen freed by the splitting of water is used in the creation of two further compounds that serve as short-term stores of energy, enabling its transfer to drive other reactions: these compounds are reduced nicotinamide adenine dinucleotide phosphate (NADPH) and adenosine triphosphate (ATP), the "energy currency" of cells. In plants, algae and cyanobacteria, long-term energy storage in the form of sugars is produced by a subsequent sequence of light-independent reactions called the Calvin cycle; some bacteria use different mechanisms, such as the reverse Krebs cycle, to achieve the same end. In the Calvin cycle, atmospheric carbon dioxide is incorporated into already existing organic carbon compounds, such as ribulose bisphosphate (RuBP).[5] Using the ATP and NADPH produced by the light-dependent reactions, the resulting compounds are then reduced and removed to form further carbohydrates, such as glucose. The first photosynthetic organisms probably evolved early in the evolutionary history of life and most likely used reducing agents such as hydrogen or hydrogen sulfide, rather than water, as sources of electrons.[6] Cyanobacteria appeared later; the excess oxygen they produced contributed directly to the oxygenation of the Earth,[7] which rendered the evolution of complex life possible. Today, the average rate of energy capture by photosynthesis globally is approximately 130 terawatts,[8][9][10] which is about eight times the current power consumption of human civilization.[11] Photosynthetic organisms also convert around 100–115 billion tons (91-104 petagrams) of carbon into biomass per year.[12][13]
  • pragmatic
    is a theory of normative philosophical ethics. Ethical pragmatists such as John Dewey believe that some societies have progressed morally in much the way they have attained progress in science. Scientists can pursue inquiry into the truth of a hypothesis and accept the hypothesis, in the sense that they act as though the hypothesis were true; nonetheless, they think that future generations can advance science, and thus future generations can refine or replace (at least some of) their accepted hypotheses. Similarly, ethical pragmatists think that norms, principles, and moral criteria are likely to be improved as a result of inquiry.
  • r
  • radiative forcing
    is the difference between insolation (sunlight) absorbed by the Earth and energy radiated back to space.[1] Changes to Earth's radiative equilibrium, that cause temperatures to rise or fall over decadal periods, are called climate forcings. [2] 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. Radiative forcing is meaningfully quantified at the tropopause and at the top of the stratosphere as flux of watts per square meter of the Earth's surface. Radiative forcing varies with insolation, the atmospheric concentrations of radiatively active gases, commonly known as greenhouse gases, and aerosols.
  • s
  • Second Law Of Thermodynamics
    The states that the total entropy of an isolated system can never decrease over time, and is constant if and only if all processes are reversible.[1] Isolated systems spontaneously evolve towards thermodynamic equilibrium, the state with maximum entropy. The total entropy of a system and its surroundings can remain constant in ideal cases where the system is in thermodynamic equilibrium, or is undergoing a (fictive) reversible process. In all processes that occur, including spontaneous processes,[2] the total entropy of the system and its surroundings increases and the process is irreversible in the thermodynamic sense. The increase in entropy accounts for the irreversibility of natural processes, and the asymmetry between future and past.[3] Historically, the second law was an empirical finding that was accepted as an axiom of thermodynamic theory. Statistical mechanics, classical or quantum, explains the microscopic origin of the law. The second law has been expressed in many ways. Its first formulation is credited to the French scientist Sadi Carnot, who in 1824 showed that there is an upper limit to the efficiency of conversion of heat to work, in a heat engine, also referred to as Carnot's rule or limit.[4]
  • snowball earth
    proposes that during one or more of Earth's icehouse climates, Earth's surface became entirely or nearly entirely frozen, sometime earlier than 650 Mya (million years ago). Proponents of the hypothesis argue that it best explains sedimentary deposits generally regarded as of glacial origin at tropical palaeolatitudes and other enigmatic features in the geological record. Opponents of the hypothesis contest the implications of the geological evidence for global glaciation and the geophysical feasibility of an ice- or slush-covered ocean[3][4] and emphasize the difficulty of escaping an all-frozen condition. A number of unanswered questions remain, including whether the Earth was a full snowball, or a "slushball" with a thin equatorial band of open (or seasonally open) water. The snowball-Earth episodes are proposed to have occurred before the sudden radiation of multicellular bioforms, known as the Cambrian explosion. The most recent snowball episode may have triggered the evolution of multicellularity. Another, much earlier and longer snowball episode, the Huronian glaciation, which would have occurred 2400 to 2100 Mya, may have been triggered by the first appearance of oxygen in the atmosphere, the "Great Oxygenation Event".
  • 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.[5] 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 20 km (66,000 ft; 12 mi), around 10 km (33,000 ft; 6.2 mi) at midlatitudes, and at about 7 km (23,000 ft; 4.3 mi) at the poles.[5] Temperatures range from an average of −51 °C (−60 °F; 220 K) near the tropopause to an average of −15 °C (5.0 °F; 260 K) near the mesosphere.[6] Stratospheric temperatures also vary within the stratosphere as the seasons change, reaching particularly low temperatures in the polar night (winter).[7] Winds in the stratosphere can far exceed those in the troposphere, reaching near 60 m/s (220 km/h; 130 mph) in the Southern polar vortex.[7]
  • Supply Limited Reach
    In general river hydraulics, a river is said to carry two things; water and sediments. The ratio of one to the other affects many things from physical and chemical properties to the river's morphology, and the last one is the most important. Sediments in rivers are constantly in motion, so scour and deposition are always happening but balancing each other. Most rivers in the Caribbean are supply limited. The only Caribbean island that has capacity limited rivers is Haiti. The high population of goats in Haiti eats virtually all of the erosion-resistant landcover and that is the reason that we can only observe Caribbean trench rivers only on this island.A river is said to be supply limited if its receiving runoff does not carry the necessary sediment load to maintain the reach stability. A river is morphologically stable if it receives the necessary sediments/water ratio to maintain reach stability.
  • t
  • troposphere
    is the lowest layer of Earth's atmosphere, and is also where nearly all weather conditions take place. It contains 75% of the atmosphere's mass and 99% of the total mass of water vapour and aerosols.[2] The average height of the troposphere is 18 km (11 mi; 59,000 ft) in the tropics, 17 km (11 mi; 56,000 ft) in the middle latitudes, and 6 km (3.7 mi; 20,000 ft) in the polar regions in winter. The total average height of the troposphere is 13 km. The lowest part of the troposphere, where friction with the Earth's surface influences air flow, is the planetary boundary layer. This layer is typically a few hundred meters to 2 km (1.2 mi; 6,600 ft) deep depending on the landform and time of day. Atop the troposphere is the tropopause, which is the border between the troposphere and stratosphere. The tropopause is an inversion layer, where the air temperature ceases to decrease with height and remains constant through its thickness.[3] The word troposphere is derived from the Greek tropos (meaning "turn, turn toward, change") and sphere (as in the Earth), reflecting the fact that rotational turbulent mixing plays an important role in the troposphere's structure and behaviour. Most of the phenomena associated with day-to-day weather occur in the troposphere.[3]
  • u
  • UN
    The United Nations (UN) is an intergovernmental organization that aims to maintain international peace and security, develop friendly relations among nations, achieve international cooperation, and be a center for harmonizing the actions of nations.[2] It is the largest, most familiar, most internationally represented and most powerful intergovernmental organization in the world. The UN is headquartered on international territory in New York City; other main offices are in Geneva, Nairobi, Vienna and The Hague. The UN was established after World War II with the aim of preventing future wars, succeeding the ineffective League of Nations.[3] On 25 April 1945, 50 governments met in San Francisco for a conference and started drafting the UN Charter, which was adopted on 25 June 1945 and took effect on 24 October 1945, when the UN began operations. Pursuant to the Charter, the organization's objectives include maintaining international peace and security, protecting human rights, delivering humanitarian aid, promoting sustainable development, and upholding international law.[4] At its founding, the UN had 51 member states; this number grew to 193 in 2011,[5] representing the vast majority of the world's sovereign states. The organization's mission to preserve world peace was complicated in its early decades by the Cold War between the United States and Soviet Union and their respective allies. Its missions have consisted primarily of unarmed military observers and lightly armed troops with primarily monitoring, reporting and confidence-building roles.[6] UN membership grew significantly following widespread decolonization beginning in the 1960s. Since then, 80 former colonies have gained independence, including 11 trust territories that had been monitored by the Trusteeship Council.[7] By the 1970s, the UN's budget for economic and social development programmes far outstripped its spending on peacekeeping. After the end of the Cold War, the UN shifted and expanded its field operations, undertaking a wide variety of complex tasks.[8] The UN has six principal organs: the General Assembly; the Security Council; the Economic and Social Council (ECOSOC); the Trusteeship Council; the International Court of Justice; and the UN Secretariat. The UN System includes a multitude of specialized agencies, such as the World Bank Group, the World Health Organization, the World Food Programme, UNESCO, and UNICEF. Additionally, non-governmental organizations may be granted consultative status with ECOSOC and other agencies to participate in the UN's work. The UN's chief administrative officer is the Secretary-General, currently Portuguese politician and diplomat António Guterres, since 1 January 2017. The organization is financed by assessed and voluntary contributions from its member states. The UN, its officers, and its agencies have won many Nobel Peace Prizes, though other evaluations of its effectiveness have been mixed. Some commentators believe the organization to be an important force for peace and human development, while others have called it ineffective, biased, or corrupt.
  • United Nations
    The United Nations (UN) is an intergovernmental organization that aims to maintain international peace and security, develop friendly relations among nations, achieve international cooperation, and be a center for harmonizing the actions of nations.[2] It is the largest, most familiar, most internationally represented and most powerful intergovernmental organization in the world. The UN is headquartered on international territory in New York City; other main offices are in Geneva, Nairobi, Vienna and The Hague. The UN was established after World War II with the aim of preventing future wars, succeeding the ineffective League of Nations.[3] On 25 April 1945, 50 governments met in San Francisco for a conference and started drafting the UN Charter, which was adopted on 25 June 1945 and took effect on 24 October 1945, when the UN began operations. Pursuant to the Charter, the organization's objectives include maintaining international peace and security, protecting human rights, delivering humanitarian aid, promoting sustainable development, and upholding international law.[4] At its founding, the UN had 51 member states; this number grew to 193 in 2011,[5] representing the vast majority of the world's sovereign states. The organization's mission to preserve world peace was complicated in its early decades by the Cold War between the United States and Soviet Union and their respective allies. Its missions have consisted primarily of unarmed military observers and lightly armed troops with primarily monitoring, reporting and confidence-building roles.[6] UN membership grew significantly following widespread decolonization beginning in the 1960s. Since then, 80 former colonies have gained independence, including 11 trust territories that had been monitored by the Trusteeship Council.[7] By the 1970s, the UN's budget for economic and social development programmes far outstripped its spending on peacekeeping. After the end of the Cold War, the UN shifted and expanded its field operations, undertaking a wide variety of complex tasks.[8] The UN has six principal organs: the General Assembly; the Security Council; the Economic and Social Council (ECOSOC); the Trusteeship Council; the International Court of Justice; and the UN Secretariat. The UN System includes a multitude of specialized agencies, such as the World Bank Group, the World Health Organization, the World Food Programme, UNESCO, and UNICEF. Additionally, non-governmental organizations may be granted consultative status with ECOSOC and other agencies to participate in the UN's work. The UN's chief administrative officer is the Secretary-General, currently Portuguese politician and diplomat António Guterres, since 1 January 2017. The organization is financed by assessed and voluntary contributions from its member states. The UN, its officers, and its agencies have won many Nobel Peace Prizes, though other evaluations of its effectiveness have been mixed. Some commentators believe the organization to be an important force for peace and human development, while others have called it ineffective, biased, or corrupt.
>