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Anarchism | 12 | Anarchism is a political philosophy and movement that is skeptical of all justifications for authority and seeks to abolish the institutions it claims maintain unnecessary coercion and hierarchy, typically including nation-states, and capitalism. Anarchism advocates for the replacement of the state with stateless socie... | |
Anarchism | 12 | Humans have lived in societies without formal hierarchies long before the establishment of states, realms, or empires. With the rise of organised hierarchical bodies, scepticism toward authority also rose. Although traces of anarchist ideas are found all throughout history, modern anarchism emerged from the Enlightenme... | |
Anarchism | 12 | Anarchists employ diverse approaches, which may be generally divided into revolutionary and evolutionary strategies; there is significant overlap between the two. Evolutionary methods try to simulate what an anarchist society might be like, but revolutionary tactics, which have historically taken a violent turn, aim to... | |
Anarchism | 12 | Etymology, terminology, and definition | The etymological origin of anarchism is from the Ancient Greek anarkhia, meaning "without a ruler", composed of the prefix an- ("without") and the word arkhos ("leader" or "ruler"). The suffix -ism denotes the ideological current that favours anarchy. Anarchism appears in English from 1642 as anarchisme and anarchy fro... |
Anarchism | 12 | Etymology, terminology, and definition | The first political philosopher to call himself an anarchist (French: anarchiste) was Pierre-Joseph Proudhon (1809–1865), marking the formal birth of anarchism in the mid-19th century. Since the 1890s and beginning in France, libertarianism has often been used as a synonym for anarchism and its use as a synonym is stil... |
Anarchism | 12 | Etymology, terminology, and definition | While the term libertarian has been largely synonymous with anarchism, its meaning has more recently been diluted by wider adoption from ideologically disparate groups, including both the New Left and libertarian Marxists, who do not associate themselves with authoritarian socialists or a vanguard party, and extreme cu... |
Anarchism | 12 | Etymology, terminology, and definition | While opposition to the state is central to anarchist thought, defining anarchism is not an easy task for scholars, as there is a lot of discussion among scholars and anarchists on the matter, and various currents perceive anarchism slightly differently. Major definitional elements include the will for a non-coercive s... |
Anarchism | 12 | History | Before the creation of towns and cities, established authority did not exist. It was after the institution of authority that anarchistic ideas were espoused as a reaction. The most notable precursors to anarchism in the ancient world were in China and Greece. In China, philosophical anarchism (the discussion on the leg... |
Anarchism | 12 | History | Anarchic attitudes were also articulated by tragedians and philosophers in Greece. Aeschylus and Sophocles used the myth of Antigone to illustrate the conflict between laws imposed by the state and personal autonomy. Socrates questioned Athenian authorities constantly and insisted on the right of individual freedom of ... |
Anarchism | 12 | History | In medieval Europe, there was no anarchistic activity except some ascetic religious movements. These, and other Muslim movements, later gave birth to religious anarchism. In the Sasanian Empire, Mazdak called for an egalitarian society and the abolition of monarchy, only to be soon executed by Emperor Kavad I. |
Anarchism | 12 | History | In Basra, religious sects preached against the state. In Europe, various sects developed anti-state and libertarian tendencies. Renewed interest in antiquity during the Renaissance and in private judgment during the Reformation restored elements of anti-authoritarian secularism, particularly in France. Enlightenment ch... |
Anarchism | 12 | History | During the French Revolution, partisan groups such as the Enragés and the sans-culottes saw a turning point in the fermentation of anti-state and federalist sentiments. The first anarchist currents developed throughout the 18th century as William Godwin espoused philosophical anarchism in England, morally delegitimisin... |
Anarchism | 12 | History | Drawing from mutualism, Mikhail Bakunin founded collectivist anarchism and entered the International Workingmen's Association, a class worker union later known as the First International that formed in 1864 to unite diverse revolutionary currents. The International became a significant political force, with Karl Marx b... |
Anarchism | 12 | History | By the turn of the 20th century, anarchism had spread all over the world. It was a notable feature of the international syndicalist movement. In China, small groups of students imported the humanistic pro-science version of anarcho-communism. Tokyo was a hotspot for rebellious youth from East Asian countries, who moved... |
Anarchism | 12 | History | Despite concerns, anarchists enthusiastically participated in the Russian Revolution in opposition to the White movement, especially in the Makhnovshchina; however, they met harsh suppression after the Bolshevik government had stabilised, including during the Kronstadt rebellion. Several anarchists from Petrograd and M... |
Anarchism | 12 | History | In the Spanish Civil War of 1936–39, anarchists and syndicalists (CNT and FAI) once again allied themselves with various currents of leftists. A long tradition of Spanish anarchism led to anarchists playing a pivotal role in the war, and particularly in the Spanish Revolution of 1936. In response to the army rebellion,... |
Anarchism | 12 | History | By the end of World War II, the anarchist movement had been severely weakened. The 1960s witnessed a revival of anarchism, likely caused by a perceived failure of Marxism–Leninism and tensions built by the Cold War. During this time, anarchism found a presence in other movements critical towards both capitalism and the... |
Anarchism | 12 | History | Around the turn of the 21st century, anarchism grew in popularity and influence within anti-capitalist, anti-war and anti-globalisation movements. Anarchists became known for their involvement in protests against the World Trade Organization (WTO), the Group of Eight and the World Economic Forum. During the protests, a... |
Anarchism | 12 | History | While having revolutionary aspirations, many forms of anarchism are not confrontational nowadays. Instead, they are trying to build an alternative way of social organization, based on mutual interdependence and voluntary cooperation. Scholar Carissa Honeywell takes the example of Food not Bombs group of collectives, to... |
Anarchism | 12 | History | |
Anarchism | 12 | Thought | Anarchist schools of thought have been generally grouped into two main historical traditions, social anarchism and individualist anarchism, owing to their different origins, values and evolution. The individualist current emphasises negative liberty in opposing restraints upon the free individual, while the social curr... |
Anarchism | 12 | Thought | Beyond the specific factions of anarchist movements which constitute political anarchism lies philosophical anarchism which holds that the state lacks moral legitimacy, without necessarily accepting the imperative of revolution to eliminate it. A component especially of individualist anarchism, philosophical anarchism ... |
Anarchism | 12 | Thought | Anarchism is usually placed on the far-left of the political spectrum. Much of its economics and legal philosophy reflect anti-authoritarian, anti-statist, libertarian, and radical interpretations of left-wing and socialist politics such as collectivism, communism, individualism, mutualism, and syndicalism, among other... |
Anarchism | 12 | Thought | Inceptive currents among classical anarchist currents were mutualism and individualism. They were followed by the major currents of social anarchism (collectivist, communist and syndicalist). They differ on organisational and economic aspects of their ideal society. |
Anarchism | 12 | Thought | Mutualism is an 18th-century economic theory that was developed into anarchist theory by Pierre-Joseph Proudhon. Its aims include "abolishing the state", reciprocity, free association, voluntary contract, federation and monetary reform of both credit and currency that would be regulated by a bank of the people. Mutuali... |
Anarchism | 12 | Thought | Anarcho-communism is a theory of anarchism that advocates a communist society with common ownership of the means of production, held by a federal network of voluntary associations, with production and consumption based on the guiding principle "From each according to his ability, to each according to his need." Anarcho... |
Anarchism | 12 | Thought | Individualist anarchism is a set of several traditions of thought within the anarchist movement that emphasise the individual and their will over any kinds of external determinants. Early influences on individualist forms of anarchism include William Godwin, Max Stirner, and Henry David Thoreau. Through many countries,... |
Anarchism | 12 | Thought | Anarchist principles undergird contemporary radical social movements of the left. Interest in the anarchist movement developed alongside momentum in the anti-globalisation movement, whose leading activist networks were anarchist in orientation. As the movement shaped 21st century radicalism, wider embrace of anarchist ... |
Anarchism | 12 | Thought | Contemporary news coverage which emphasizes black bloc demonstrations has reinforced anarchism's historical association with chaos and violence. Its publicity has also led more scholars in fields such as anthropology and history to engage with the anarchist movement, although contemporary anarchism favours actions over... |
Anarchism | 12 | Thought | Anarchists are generally committed against coercive authority in all forms, namely "all centralized and hierarchical forms of government (e.g., monarchy, representative democracy, state socialism, etc.), economic class systems (e.g., capitalism, Bolshevism, feudalism, slavery, etc.), autocratic religions (e.g., fundame... |
Anarchism | 12 | Tactics | Anarchists' tactics take various forms but in general serve two major goals, namely, to first oppose the Establishment and secondly to promote anarchist ethics and reflect an anarchist vision of society, illustrating the unity of means and ends. A broad categorisation can be made between aims to destroy oppressive stat... |
Anarchism | 12 | Tactics | Anarchist tactics have shifted during the course of the last century. Anarchists during the early 20th century focused more on strikes and militancy while contemporary anarchists use a broader array of approaches. |
Anarchism | 12 | Tactics | During the classical era, anarchists had a militant tendency. Not only did they confront state armed forces, as in Spain and Ukraine, but some of them also employed terrorism as propaganda of the deed. Assassination attempts were carried out against heads of state, some of which were successful. Anarchists also took pa... |
Anarchism | 12 | Tactics | Anarchist perspectives towards violence have always been controversial. Anarcho-pacifists advocate for non-violence means to achieve their stateless, nonviolent ends. Other anarchist groups advocate direct action, a tactic which can include acts of sabotage or terrorism. This attitude was quite prominent a century ago ... |
Anarchism | 12 | Tactics | Anarchists took an active role in strike actions, although they tended to be antipathetic to formal syndicalism, seeing it as reformist. They saw it as a part of the movement which sought to overthrow the state and capitalism. Anarchists also reinforced their propaganda within the arts, some of whom practiced naturism ... |
Anarchism | 12 | Tactics | In the current era, Italian anarchist Alfredo Bonanno, a proponent of insurrectionary anarchism, has reinstated the debate on violence by rejecting the nonviolence tactic adopted since the late 19th century by Kropotkin and other prominent anarchists afterwards. Both Bonanno and the French group The Invisible Committee... |
Anarchism | 12 | Tactics | Overall, contemporary anarchists are much less violent and militant than their ideological ancestors. They mostly engage in confronting the police during demonstrations and riots, especially in countries such as Canada, Greece, and Mexico. Militant black bloc protest groups are known for clashing with the police; howev... |
Anarchism | 12 | Tactics | Anarchists commonly employ direct action. This can take the form of disrupting and protesting against unjust hierarchy, or the form of self-managing their lives through the creation of counter-institutions such as communes and non-hierarchical collectives. Decision-making is often handled in an anti-authoritarian way, ... |
Anarchism | 12 | Tactics | The decision-making process of small anarchist affinity groups plays a significant tactical role. Anarchists have employed various methods in order to build a rough consensus among members of their group without the need of a leader or a leading group. One way is for an individual from the group to play the role of fac... |
Anarchism | 12 | Tactics | As in the past, newspapers and journals are used, and anarchists have gone online in the World Wide Web to spread their message. Anarchists have found it easier to create websites because of distributional and other difficulties, hosting electronic libraries and other portals. Anarchists were also involved in developin... |
Anarchism | 12 | Tactics | Anarchists organize themselves to squat and reclaim public spaces. During important events such as protests and when spaces are being occupied, they are often called Temporary Autonomous Zones (TAZ), spaces where art, poetry, and surrealism are blended to display the anarchist ideal. As seen by anarchists, squatting is... |
Anarchism | 12 | Key issues | As anarchism is a philosophy that embodies many diverse attitudes, tendencies, and schools of thought; disagreement over questions of values, ideology, and tactics is common. Its diversity has led to widely different uses of identical terms among different anarchist traditions which has created a number of definitional... |
Anarchism | 12 | Key issues | Objection to the state and its institutions is a sine qua non of anarchism. Anarchists consider the state as a tool of domination and believe it to be illegitimate regardless of its political tendencies. Instead of people being able to control the aspects of their life, major decisions are taken by a small elite. Autho... |
Anarchism | 12 | Key issues | Specific anarchist attitudes towards the state vary. Robert Paul Wolff believed that the tension between authority and autonomy would mean the state could never be legitimate. Bakunin saw the state as meaning "coercion, domination by means of coercion, camouflaged if possible but unceremonious and overt if need be." A.... |
Anarchism | 12 | Key issues | As gender and sexuality carry along them dynamics of hierarchy, many anarchists address, analyse, and oppose the suppression of one's autonomy imposed by gender roles. |
Anarchism | 12 | Key issues | Sexuality was not often discussed by classical anarchists but the few that did felt that an anarchist society would lead to sexuality naturally developing. Sexual violence was a concern for anarchists such as Benjamin Tucker, who opposed age of consent laws, believing they would benefit predatory men. A historical curr... |
Anarchism | 12 | Key issues | During the second half of the 20th century, anarchism intermingled with the second wave of feminism, radicalising some currents of the feminist movement and being influenced as well. By the latest decades of the 20th century, anarchists and feminists were advocating for the rights and autonomy of women, gays, queers an... |
Anarchism | 12 | Key issues | The interest of anarchists in education stretches back to the first emergence of classical anarchism. Anarchists consider proper education, one which sets the foundations of the future autonomy of the individual and the society, to be an act of mutual aid. Anarchist writers such as William Godwin (Political Justice) an... |
Anarchism | 12 | Key issues | In 1901, Catalan anarchist and free thinker Francisco Ferrer established the Escuela Moderna in Barcelona as an opposition to the established education system which was dictated largely by the Catholic Church. Ferrer's approach was secular, rejecting both state and church involvement in the educational process whilst g... |
Anarchism | 12 | Key issues | Anarchist education is based largely on the idea that a child's right to develop freely and without manipulation ought to be respected and that rationality would lead children to morally good conclusions; however, there has been little consensus among anarchist figures as to what constitutes manipulation. Ferrer believ... |
Anarchism | 12 | Key issues | Late 20th century and contemporary anarchist writers (Paul Goodman, Herbert Read, and Colin Ward) intensified and expanded the anarchist critique of state education, largely focusing on the need for a system that focuses on children's creativity rather than on their ability to attain a career or participate in consumer... |
Anarchism | 12 | Key issues | While few anarchist education institutions have survived to the modern-day, major tenets of anarchist schools, among them respect for child autonomy and relying on reasoning rather than indoctrination as a teaching method, have spread among mainstream educational institutions. Judith Suissa names three schools as expli... |
Anarchism | 12 | Key issues | The connection between anarchism and art was quite profound during the classical era of anarchism, especially among artistic currents that were developing during that era such as futurists, surrealists and others. In literature, anarchism was mostly associated with the New Apocalyptics and the neo-romanticism movement.... |
Anarchism | 12 | Key issues | Other anarchists advocated for or used art as a means to achieve anarchist ends. In his book Breaking the Spell: A History of Anarchist Filmmakers, Videotape Guerrillas, and Digital Ninjas, Chris Robé claims that "anarchist-inflected practices have increasingly structured movement-based video activism." Throughout the ... |
Anarchism | 12 | Key issues | Three overlapping properties made art useful to anarchists. It could depict a critique of existing society and hierarchies, serve as a prefigurative tool to reflect the anarchist ideal society and even turn into a means of direct action such as in protests. As it appeals to both emotion and reason, art could appeal to ... |
Anarchism | 12 | Criticism | The most common critique of anarchism is the assertion that humans cannot self-govern and so a state is necessary for human survival. Philosopher Bertrand Russell supported this critique, stating that "[p]eace and war, tariffs, regulations of sanitary conditions and the sale of noxious drugs, the preservation of a just... |
Anarchism | 12 | Criticism | Another criticism of anarchism is the belief that it is inherently unstable: that an anarchist society would inevitably evolve back into a state. Thomas Hobbes and other early social contract theorists argued that the state emerges in response to natural anarchy in order to protect the people's interests and keep order... |
Anarchism | 12 | Criticism | Philosophy lecturer Andrew G. Fiala composed a list of common arguments against anarchism which includes critiques such as that anarchism is innately related to violence and destruction, not only in the pragmatic world, such as at protests, but in the world of ethics as well. Secondly, anarchism is evaluated as unfeasi... |
Anarchism | 12 | Criticism | Philosophical anarchism has met the criticism of members of academia following the release of pro-anarchist books such as A. John Simmons' Moral Principles and Political Obligations. Law professor William A. Edmundson authored an essay to argue against three major philosophical anarchist principles which he finds falla... |
Anarchism | 12 | Criticism | One of the earliest criticisms is that anarchism defies and fails to understand the biological inclination to authority. Joseph Raz states that the acceptance of authority implies the belief that following their instructions will afford more success. Raz believes that this argument is true in following both authorities... |
Anarchism | 12 | Criticism | Friedrich Engels, considered to be one of the principal founders of Marxism, criticised anarchism's anti-authoritarianism as inherently counter-revolutionary because in his view a revolution is by itself authoritarian. Academic John Molyneux writes in his book Anarchism: A Marxist Criticism that "anarchism cannot win",... |
Albedo | 39 | Albedo (/ælˈbiːdoʊ/; from Latin albedo 'whiteness') is the fraction of sunlight that is diffusely reflected by a body. It is 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). | |
Albedo | 39 | Surface albedo is defined as the ratio of radiosity Je to the irradiance Ee (flux per unit area) received by a surface. 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. These factors va... | |
Albedo | 39 | Unless given for a specific wavelength (spectral albedo), albedo refers to the entire spectrum of solar radiation. 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 w... | |
Albedo | 39 | Ice–albedo feedback is a positive feedback climate process where a change in the area of ice caps, glaciers, and sea ice alters the albedo and surface temperature of a planet. Ice is very reflective, therefore it reflects far more solar energy back to space than the other types of land area or open water. Ice–albedo fe... | |
Albedo | 39 | Albedo is an important concept in climatology, astronomy, and environmental management. 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. | |
Albedo | 39 | Terrestrial albedo | Any albedo in visible light falls within a range of about 0.9 for fresh snow to about 0.04 for charcoal, one of the darkest substances. Deeply shadowed cavities can achieve an effective albedo approaching the zero of a black body. When seen from a distance, the ocean surface has a low albedo, as do most forests, wherea... |
Albedo | 39 | Terrestrial albedo | Earth's surface albedo is regularly estimated via Earth observation satellite sensors such as NASA's MODIS instruments on board the Terra and Aqua satellites, and the CERES instrument on the Suomi NPP and JPSS. As the amount of reflected radiation is only measured for a single direction by satellite, not all directions... |
Albedo | 39 | Terrestrial albedo | Earth's average surface temperature due to its albedo and the greenhouse effect is currently about 15 °C (59 °F). If Earth were frozen entirely (and hence be more reflective), the average temperature of the planet would drop below −40 °C (−40 °F). If only the continental land masses became covered by glaciers, the mean... |
Albedo | 39 | Terrestrial albedo | In 2021, scientists reported that Earth dimmed by ~0.5% over two decades (1998–2017) as measured by earthshine using modern photometric techniques. This may have both been co-caused by climate change as well as a substantial increase in global warming. However, the link to climate change has not been explored to date a... |
Albedo | 39 | Terrestrial albedo | For land surfaces, it has been shown that the albedo at a particular solar zenith angle θi can be approximated by the proportionate sum of two terms: |
Albedo | 39 | Terrestrial albedo | with 1 − D {\displaystyle {1-D}} being the proportion of direct radiation from a given solar angle, and D {\displaystyle {D}} being the proportion of diffuse illumination, the actual albedo α {\displaystyle {\alpha }} (also called blue-sky albedo) can then be given as: |
Albedo | 39 | Terrestrial albedo | This formula is important because it allows the albedo to be calculated for any given illumination conditions from a knowledge of the intrinsic properties of the surface. |
Albedo | 39 | Terrestrial albedo | Human activities (e.g., deforestation, farming, and urbanization) change the albedo of various areas around the globe. As per Campra et al., human impacts to "the physical properties of the land surface can perturb the climate by altering the Earth’s radiative energy balance" even on a small scale or when undetected by... |
Albedo | 39 | Terrestrial albedo | The tens of thousands of hectares of greenhouses in Almería, Spain form a large expanse of whitened plastic roofs. A 2008 study found that this anthropogenic change lowered the local surface area temperature of the high-albedo area, although changes were localized. A follow-up study found that "CO2-eq. emissions associ... |
Albedo | 39 | Terrestrial albedo | It has been found that urbanization generally decreases albedo (commonly being 0.01–0.02 lower than adjacent croplands), which contributes to global warming. Deliberately increasing albedo in urban areas can mitigate urban heat island. Ouyang et al. estimated that, on a global scale, "an albedo increase of 0.1 in world... |
Albedo | 39 | Terrestrial albedo | Intentionally enhancing the albedo of the Earth's surface, along with its daytime thermal emittance, has been proposed as a solar radiation management strategy to mitigate energy crises and global warming known as passive daytime radiative cooling (PDRC). Efforts toward widespread implementation of PDRCs may focus on m... |
Albedo | 39 | Examples of terrestrial albedo effects | Albedo is not directly dependent on illumination because changing the amount of incoming light proportionally changes the amount of reflected light, except in circumstances where a change in illumination induces a change in the Earth's surface at that location (e.g. through melting of reflective ice). That said, albedo... |
Albedo | 39 | Examples of terrestrial albedo effects | The intensity of albedo temperature effects depends on the amount of albedo and the level of local insolation (solar irradiance); high albedo areas in the Arctic and Antarctic regions are cold due to low insolation, whereas areas such as the Sahara Desert, which also have a relatively high albedo, will be hotter due to... |
Albedo | 39 | Examples of terrestrial albedo effects | Arctic regions notably release more heat back into space than what they absorb, effectively cooling the Earth. This has been a concern since arctic ice and snow has been melting at higher rates due to higher temperatures, creating regions in the arctic that are notably darker (being water or ground which is darker colo... |
Albedo | 39 | Examples of terrestrial albedo effects | Albedo affects climate by determining how much radiation a planet absorbs. The uneven heating of Earth from albedo variations between land, ice, or ocean surfaces can drive weather. |
Albedo | 39 | Examples of terrestrial albedo effects | The response of the climate system to an initial forcing is modified by feedbacks: increased by "self-reinforcing" or "positive" feedbacks and reduced by "balancing" or "negative" feedbacks. The main reinforcing feedbacks are the water-vapour feedback, the ice–albedo feedback, and the net effect of clouds. |
Albedo | 39 | Examples of terrestrial albedo effects | When an area's albedo changes due to snowfall, a snow–temperature feedback results. A layer of snowfall increases local albedo, reflecting away sunlight, leading to local cooling. In principle, if no outside temperature change affects this area (e.g., a warm air mass), the raised albedo and lower temperature would main... |
Albedo | 39 | Examples of terrestrial albedo effects | Snow albedo is highly variable, ranging from as high as 0.9 for freshly fallen snow, to about 0.4 for melting snow, and as low as 0.2 for dirty snow. Over Antarctica snow albedo averages a little more than 0.8. If a marginally snow-covered area warms, snow tends to melt, lowering the albedo, and hence leading to more s... |
Albedo | 39 | Examples of terrestrial albedo effects | Just as fresh snow has a higher albedo than does dirty snow, the albedo of snow-covered sea ice is far higher than that of sea water. Sea water absorbs more solar radiation than would the same surface covered with reflective snow. When sea ice melts, either due to a rise in sea temperature or in response to increased s... |
Albedo | 39 | Examples of terrestrial albedo effects | Cryoconite, powdery windblown dust containing soot, sometimes reduces albedo on glaciers and ice sheets. |
Albedo | 39 | Examples of terrestrial albedo effects | The dynamical nature of albedo in response to positive feedback, together with the effects of small errors in the measurement of albedo, can lead to large errors in energy estimates. Because of this, in order to reduce the error of energy estimates, it is important to measure the albedo of snow-covered areas through re... |
Albedo | 39 | Examples of terrestrial albedo effects | Albedo works on a smaller scale, too. In sunlight, dark clothes absorb more heat and light-coloured clothes reflect it better, thus allowing some control over body temperature by exploiting the albedo effect of the colour of external clothing. |
Albedo | 39 | Examples of terrestrial albedo effects | Albedo can affect the electrical energy output of solar photovoltaic devices. For example, the effects of a spectrally responsive albedo are illustrated by the differences between the spectrally weighted albedo of solar photovoltaic technology based on hydrogenated amorphous silicon (a-Si:H) and crystalline silicon (c-... |
Albedo | 39 | Examples of terrestrial albedo effects | Forests generally have a low albedo because the majority of the ultraviolet and visible spectrum is absorbed through photosynthesis. For this reason, the greater heat absorption by trees could offset some of the carbon benefits of afforestation (or offset the negative climate impacts of deforestation). In other words: ... |
Albedo | 39 | Examples of terrestrial albedo effects | In the case of evergreen forests with seasonal snow cover albedo reduction may be great enough for deforestation to cause a net cooling effect. Trees also impact climate in extremely complicated ways through evapotranspiration. The water vapor causes cooling on the land surface, causes heating where it condenses, acts ... |
Albedo | 39 | Examples of terrestrial albedo effects | Mid-to-high-latitude forests have a much lower albedo during snow seasons than flat ground, thus contributing to warming. Modeling that compares the effects of albedo differences between forests and grasslands suggests that expanding the land area of forests in temperate zones offers only a temporary mitigation benefit... |
Albedo | 39 | Examples of terrestrial albedo effects | In seasonally snow-covered zones, winter albedos of treeless areas are 10% to 50% higher than nearby forested areas because snow does not cover the trees as readily. Deciduous trees have an albedo value of about 0.15 to 0.18 whereas coniferous trees have a value of about 0.09 to 0.15. Variation in summer albedo across ... |
Albedo | 39 | Examples of terrestrial albedo effects | Studies by the Hadley Centre have investigated the relative (generally warming) effect of albedo change and (cooling) effect of carbon sequestration on planting forests. They found that new forests in tropical and midlatitude areas tended to cool; new forests in high latitudes (e.g., Siberia) were neutral or perhaps wa... |
Albedo | 39 | Examples of terrestrial albedo effects | Water reflects light very differently from typical terrestrial materials. The reflectivity of a water surface is calculated using the Fresnel equations. |
Albedo | 39 | Examples of terrestrial albedo effects | At the scale of the wavelength of light even wavy water is always smooth so the light is reflected in a locally specular manner (not diffusely). The glint of light off water is a commonplace effect of this. At small angles of incident light, waviness results in reduced reflectivity because of the steepness of the refle... |
Albedo | 39 | Examples of terrestrial albedo effects | Although the reflectivity of water is very low at low and medium angles of incident light, it becomes very high at high angles of incident light such as those that occur on the illuminated side of Earth near the terminator (early morning, late afternoon, and near the poles). However, as mentioned above, waviness causes... |
Albedo | 39 | Examples of terrestrial albedo effects | Note that white caps on waves look white (and have high albedo) because the water is foamed up, so there are many superimposed bubble surfaces which reflect, adding up their reflectivities. Fresh 'black' ice exhibits Fresnel reflection. Snow on top of this sea ice increases the albedo to 0.9. |
Albedo | 39 | Examples of terrestrial albedo effects | Cloud albedo has substantial influence over atmospheric temperatures. Different types of clouds exhibit different reflectivity, theoretically ranging in albedo from a minimum of near 0 to a maximum approaching 0.8. "On any given day, about half of Earth is covered by clouds, which reflect more sunlight than land and wa... |
Albedo | 39 | Examples of terrestrial albedo effects | Albedo and climate in some areas are affected by artificial clouds, such as those created by the contrails of heavy commercial airliner traffic. A study following the burning of the Kuwaiti oil fields during Iraqi occupation showed that temperatures under the burning oil fires were as much as 10 °C (18 °F) colder than ... |
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