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Encyclopedia > Global dimming
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Global dimming is the gradual reduction in the amount of global direct irradiance at the Earth's surface that was observed for several decades after the start of systematic measurements in 1950s. It is thought to have been caused by an increase in particulates such as sulfur aerosols in the atmosphere due to human action. The effect varied by location, but worldwide it was of the order of a 4% reduction over the three decades from 1960–1990. The trend reversed during the past decade. Global dimming has interfered with the hydrological cycle by reducing evaporation and may have caused droughts in some areas. Global dimming also creates a cooling effect that may have partially masked the effect of greenhouse gases on global warming. It has been suggested that Pollutant be merged into this article or section. ... Air pollution is a chemical, particulate matter, or biological agent that modifies the natural characteristics of the atmosphere. ... The term acid rain Since the industrial revolution, emissions of sulfur and nitrogen oxides to the atmosphere have increased. ... An air quality measurement station in Edinburgh, Scotland The Air Quality Index (AQI) is a standardized indicator of the air quality in a given location. ... Atmospheric dispersion modeling is performed with computer programs that use mathematical equations and algorithms to simulate how pollutants in the ambient atmosphere disperse in the atmosphere. ... Tetrafluoroethane (a haloalkane) is a clear liquid which boils well below room temperature (as seen here) and can be extracted from common canned air canisters by simply inverting them during use. ... Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ... Haze is an atmospheric phenomenon where dust, smoke and other pollutant particles obscure the normal clarity of the sky. ... Indoor Air Quality (IAQ) deals with the content of interior air that could affect health and comfort of building occupants. ... Global monthly average total ozone amount Ozone depletion describes two distinct, but related observations: a slow, steady decline of about 4 percent per decade in the total amount of ozone in Earths stratosphere since around 1980; and a much larger, but seasonal, decrease in stratospheric ozone over Earths... Particulates, alternatively referred to as particulate matter (PM), aerosols or fine particles, are tiny particles of solid or liquid suspended in a gas. ... It has been suggested that Haze be merged into this article or section. ... Raw sewage and industrial waste flows into the U.S. from Mexico as the New River passes from Mexicali, Baja California to Calexico, California Water pollution is a large set of adverse effects upon water bodies such as lakes, rivers, oceans, and groundwater caused by human activities. ... 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Top: Increasing atmospheric CO2 levels as measured in the atmosphere and ice cores. ... Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ...

Contents

Cause and effects

Further information: Albedoirradiance, and insolation

It is thought that global dimming was probably due to the increased presence of aerosol particles in the atmosphere caused by human action. Aerosols and other particulates absorb solar energy and reflect sunlight back into space. The pollutants can also become nuclei for cloud droplets. It is also thought that the water droplets in clouds coalesce around the particles. Increased pollution causes more particulates and thereby creates clouds consisting of a greater number of smaller droplets (that is, the same amount of water is spread over more droplets). The smaller droplets make clouds more reflective, so that more incoming sunlight is reflected back into space and less reaches the earth's surface. Albedo is the ratio of reflected to incident electromagnetic radiation. ... Irradiance, radiant emittance, and radiant exitance are radiometry terms for the power of electromagnetic radiation at a surface, per unit area. ... Not to be confused with insulation. ... Particulates, alternatively referred to as particulate matter (PM), aerosols or fine particles, are tiny particles of solid or liquid suspended in a gas. ... “Air” redirects here. ... Aerosol pollution over Northern India and Bangladesh - NASA Cloud condensation nuclei or CCNs (also known as cloud seeds) are small particles (typically 0. ... For other uses, see Cloud (disambiguation). ... Coalescence is the process by which two or more droplets (or bubbles) merge during contact to form a single daughter droplet (or bubble). ... Albedo is the ratio of reflected to incident electromagnetic radiation. ...


Clouds intercept both heat from the sun and heat radiated from the Earth. Their effects are complex and vary in time, location and altitude. Usually during the daytime the interception of sunlight predominates, giving a cooling effect; however, at night the re-radiation of heat to the Earth slows the Earth's heat loss. Also it has been thought that humans help produce the particles in the earth's atmosphere, resulting in global dimming.

Research

Further information: Climate model and pyranometer
Eastern China. Dozens of fires burning on the surface (red dots) and a thick pall of smoke and haze (greyish pixels) filling the skies overhead. Photo taken by MODIS aboard NASA's Aqua satellite
Eastern China. Dozens of fires burning on the surface (red dots) and a thick pall of smoke and haze (greyish pixels) filling the skies overhead. Photo taken by MODIS aboard NASA's Aqua satellite

In the late-1960s, Mikhail Ivanovich Budyko worked with simple two-dimensional energy-balance climate models to investigate the reflectivity of ice.[1] He found that the ice-albedo feedback created a positive feedback loop in the Earth's climate system. The more snow and ice, the more solar radiation is reflected back into space and hence the colder Earth grows and the more it snows. Other studies found that pollution or a volcano eruption could snap us into an ice age.[2][3] Climate models use quantitative methods to simulate the interactions of the atmosphere, oceans, land surface, and ice. ... A pyranometer is a type of actinometer used to measure broadband solar irradiance on a planar surface. ... Image File history File links Size of this preview: 782 × 600 pixel Image in higher resolution (6000 × 4600 pixel, file size: 2. ... Image File history File links Size of this preview: 782 × 600 pixel Image in higher resolution (6000 × 4600 pixel, file size: 2. ... This article is about the American space agency. ... The 1960s decade refers to the years from 1960 to 1969, inclusive. ... Mikhail Ivanovich Budyko (Μ.И. Будыко) (1920- ) - Russian climatologist born in Gomel, now Belarus. ...


In the mid-1980s, Atsumu Ohmura, a geography researcher at the Swiss Federal Institute of Technology, found that solar radiation striking the Earth's surface had declined by more than 10% over the three previous decades. His findings are in apparent contradiction to global warming—the global temperature has steadily been going up. Less light reaching the earth would mean that it would have to cool. Ohmura published his findings "Secular variation of global radiation in Europe" in 1989.[4] This was soon followed by others. Viivi Russak in 1990 "Trends of solar radiation, cloudiness and atmospheric transparency during recent decades in Estonia",[5] and Beate Liepert in 1994 "Solar radiation in Germany - Observed trends and an assessment of their causes".[6] Dimming has also been observed in sites all over the Former Soviet Union.[7] Gerry Stanhill who studied these declines worldwide in many papers (see references) coined the term "Global dimming".[8] The 1980s refers to the years from 1980 to 1989. ... Atsumu Ohmura (born 1942) is a Japanese climatologist, known for his contributions to the theory of global dimming. ... Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ...

Golden Gate Bridge with California's characteristic brown cloud in the background — a likely contributor to global dimming. Photo CC 2004 by Aaron Logan

Independent research in Israel and the Netherlands in the late 1980s showed an apparent reduction in the amount of sunlight,[9] despite widespread evidence that the climate was actually becoming hotter. The rate of dimming varies around the world but is on average estimated at around 2–3% per decade, with the possibility that the trend reversed in the early 1990s. It is difficult to make a precise measurement, due to the difficulty in accurately calibrating the instruments used, and the problem of spatial coverage. Nonetheless, the effect is almost certainly present. Download high resolution version (900x239, 75 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (900x239, 75 KB) Wikipedia does not have an article with this exact name. ... The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the opening into the San Francisco Bay from the Pacific Ocean. ... Official language(s) English Capital Sacramento Largest city Los Angeles Largest metro area Greater Los Angeles Area  Ranked 3rd  - Total 158,302 sq mi (410,000 km²)  - Width 250 miles (400 km)  - Length 770 miles (1,240 km)  - % water 4. ... calibration refers to the process of determining the relation between the output (or response) of a measuring instrument and the value of the input quantity or attribute, a measurement standard. ...


The effect (2–3%, as above) is due to changes within the Earth's atmosphere; the value of the solar radiation at the top of the atmosphere has not changed by more than a fraction of this amount.[10]


The effect varies greatly over the planet, but estimates of the terrestrial surface average value are:

  • 5.3% (9 W/m²); over 1958–85 (Stanhill and Moreshet, 1992)[8]
  • 2%/decade over 1964–93 (Gilgen et al, 1998)[11]
  • 2.7%/decade (total 20 W/m²); up to 2000 (Stanhill and Cohen, 2001)[12]
  • 4% over 1961–90 (Liepert 2002)[13][14]

Note that these numbers are for the terrestrial surface and not really a global average. Whether dimming (or brightening) occurred over the ocean has been a bit of an unknown though a specific measurement (see below, Causes) measured effects some 400 miles (643.7 km) from India over the Indian Ocean towards the Maldives Islands. Regional effects probably dominate but are not strictly confined to the land area, and the effects will be driven by regional air circulation.


The largest reductions are found in the Northern Hemisphere mid-latitudes.[15] The region of the spectrum of light radiation most affected seems to be the visible and infrared rather than the ultraviolet part of the spectrum.[16] Northern hemisphere highlighted in yellow. ... In most modern usages of the word spectrum, there is a unifying theme of between extremes at either end. ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... For other uses, see Infrared (disambiguation). ... For other uses, see Ultraviolet (disambiguation). ...


Pan evaporation data

Further information: Pan evaporation

Over the last 50 or so years, pan evaporation has been carefully monitored. For decades, nobody took much notice of the pan evaporation measurements. But in the 1990s in Europe, Israel, and North America, scientists spotted something that at the time was considered very strange, the rate of evaporation was falling although they had expected it to increase due to global warming.*.[17] The same trend has been observed in China over a similar period. A decrease in solar irradiance is cited to be the driving force. However, unlike in other areas of the world, in China the decrease in solar irradiance was not always accompanied by an increase in cloud cover and precipitation. It is believed that aerosols may play a critical role in the decrease of solar irradiance in China.[18] Pan evaporation is a measurement that combines or integrates the effects of several climate elements: temperature, humidity, solar radiation, and wind. ... Pan evaporation is a measurement that combines or integrates the effects of several climate elements: temperature, humidity, solar radiation, and wind. ... Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ... Particulates, alternatively referred to as particulate matter (PM), aerosols or fine particles, are tiny particles of solid or liquid suspended in a gas. ...


BBC Horizon producer David Sington believes that many climate scientists regard the pan-evaporation data as the most convincing evidence of solar dimming.[19] Pan evaporation experiments are easy to reproduce with low-cost equipment, there are many pans used for agriculture all over the world and in many instances, and the data has been collected for nearly a half century. However, pan evaporation depends on some additional factors besides net radiation from the sun. The other two major factors are vapor pressure deficit and wind speed[20]. The ambient temperature turns out to be a negligible factor. The pan evaporation data corroborates the data gathered by radiometer[12][17] and fills in the gaps in the data obtained using pyranometers. With adjustments to these factors, pan evaporation data has been compared to results of climate simulations.[21] Horizon is a long-running BBC popular science and history documentary programme, notable for coining the term supervolcano. ... NOVA DVD: Dimming the Sun Earth Story: The Shaping of Our World Paradise Dreamed David Sington is a British-born producer, screenwriter, director, author and journalist. ... A radiometer is a device used to measure the radiant flux or power in electromagnetic radiation. ... A pyranometer is a type of actinometer used to measure broadband solar irradiance on a planar surface. ...


Probable causes

Further information: ParticulateBlack carbonContrail, and Volcanic ash
NASA photograph showing aircraft contrails and natural clouds. The temporary disappearance of contrails over North America due to plane groundings after the September 11, 2001 attacks, and the resulting increase in diurnal temperature range gave empirical evidence of the effect of thin ice clouds at the Earth's surface.
NASA photograph showing aircraft contrails and natural clouds. The temporary disappearance of contrails over North America due to plane groundings after the September 11, 2001 attacks, and the resulting increase in diurnal temperature range gave empirical evidence of the effect of thin ice clouds at the Earth's surface.[22]

The incomplete combustion of fossil fuels (such as diesel) and wood releases black carbon into the air. Though black carbon, most of which is soot, is an extremely small component of air pollution at land surface levels, the phenomenon has a significant heating effect on the atmosphere at altitudes above two kilometers (6,562 feet). Also, it dims the surface of the ocean by absorbing solar radiation.[23] Particulates, alternatively referred to as particulate matter (PM), aerosols or fine particles, are tiny particles of solid or liquid suspended in a gas. ... As explained by Goldberg (1985), black carbon (BC) is an impure form of carbon produced by incomplete combustion of fossil fuel and wood (forming soot) or biomass (forming charcoals). ... Contrails are condensation trails (sometimes vapour trails): artificial cirrus clouds made by the exhaust of aircraft engines or wingtip vortices which precipitate a stream of tiny ice crystals in moist, frigid upper air. ... Ash plume from Mt Cleveland, a stratovolcano Diamond Head, a well-known backdrop to Waikiki in Hawaii, is an ash cone that solidified into tuff Volcanic ash consists of very fine rock and mineral particles less than 2 mm in diameter that are ejected from a volcanic vent. ... Download high resolution version (1152x864, 502 KB)A NASA photograph of aircraft contrails, taken from I-95 in northern Virginia, January 26, 2001 by NASA scientist Louis Nguyen. ... Download high resolution version (1152x864, 502 KB)A NASA photograph of aircraft contrails, taken from I-95 in northern Virginia, January 26, 2001 by NASA scientist Louis Nguyen. ... This article is about the American space agency. ... Contrails The contrail of a four-engined jet over Bristol, England Contrails of jets travelling between the Eastern Seaboard and Europe are seen in this satellite photo of Nova Scotia. ... A sequential look at United Flight 175 crashing into the south tower of the World Trade Center The September 11, 2001 attacks (often referred to as 9/11—pronounced nine eleven or nine one one) consisted of a series of coordinated terrorist[1] suicide attacks upon the United States, predominantly... Look up day in Wiktionary, the free dictionary. ... Average maximum, minimum and range of monthly air temperatures recorded in Campinas, Brazil, between January 2001 and July 2006 Average maximum, minimum and range of monthly air temperatures recorded in Aracaju, state of Sergipe, Brazil, between January 2001 and July 2006 Temperature range is the numerical difference between the minimum... Empirical research is any activity that uses direct or indirect observation as its test of reality. ... This article is about the fuel. ... As explained by Goldberg (1985), black carbon (BC) is an impure form of carbon produced by incomplete combustion of fossil fuel and wood (forming soot) or biomass (forming charcoals). ... Soot, also called lampblack, Pigment Black 7, carbon black or black carbon, is a dark powdery deposit of unburned fuel residues, usually composed mainly of amorphous carbon, that accumulates in chimneys, automobile mufflers and other surfaces exposed to smoke—especially from the combustion of carbon-rich organic fuels in the...


Experiments in the Maldives (comparing the atmosphere over the northern and southern islands) in the 1990s showed that the effect of macroscopic pollutants in the atmosphere at that time (blown south from India) caused about a 10% reduction in sunlight reaching the surface in the area under the pollution cloud - a much greater reduction than expected from the presence of the particles themselves[24] Prior to the research being undertaken, predictions were of a 0.5–1% effect from particulate matter; the variation from prediction may be explained by cloud formation with the particles acting as the focus for droplet creation. Clouds are very effective at reflecting light back out into space. It has been suggested that Pollutant be merged into this article or section. ... Particulates, alternatively referred to as particulate matter (PM), aerosols or fine particles, are tiny particles of solid or liquid suspended in a gas. ... The reflection of a bridge in Indianapolis, Indianas Central Canal. ...


The phenomenon underlying global dimming may also have regional effects. While most of the earth has warmed, the regions that are downwind from major sources of air pollution (specifically sulfur dioxide emissions) have generally cooled. This may explain the cooling of the eastern United States relative to the warming western part.[25]


Some climate scientists have theorized that aircraft contrails (also called vapor trails) are implicated in global dimming, but the constant flow of air traffic previously meant that this could not be tested. The near-total shutdown of civil air traffic during the three days following the September 11, 2001 attacks afforded a rare opportunity in which to observe the climate of the United States absent from the effect of contrails. During this period, an increase in diurnal temperature variation of over 1 °C was observed in some parts of the U.S., i.e. aircraft contrails may have been raising nighttime temperatures and/or lowering daytime temperatures by much more than previously thought.[22] Contrails are condensation trails (sometimes vapour trails): artificial cirrus clouds made by the exhaust of aircraft engines or wingtip vortices which precipitate a stream of tiny ice crystals in moist, frigid upper air. ... Civil airliner - Air India Boeing 747-400 Civil aviation is one of two major categories of flying, representing all non-Military aviation, both private and commercial. ... A sequential look at United Flight 175 crashing into the south tower of the World Trade Center The September 11, 2001 attacks (often referred to as 9/11—pronounced nine eleven or nine one one) consisted of a series of coordinated terrorist[1] suicide attacks upon the United States, predominantly... Look up day in Wiktionary, the free dictionary. ...


Airborne volcanic ash can reflect the Sun's rays back out into space and cool the planet. Dips in earth temperatures have been observed from large volcano eruptions such as Mount Agung in Bali that erupted in 1963, El Chichon (Mexico) 1983, Ruiz (Colombia) 1985, and Pinatubo (Philippines) 1991. But even for major eruptions, the ash clouds remain only for relatively short periods.[26] Ash plume from Mt Cleveland, a stratovolcano Diamond Head, a well-known backdrop to Waikiki in Hawaii, is an ash cone that solidified into tuff Volcanic ash consists of very fine rock and mineral particles less than 2 mm in diameter that are ejected from a volcanic vent. ...


Recent reversal of the trend

Further information: Clean Air Act
Sun-blocking aerosols around the world steadily declined (red line) since the 1991 eruption of Mount Pinatubo, according to satellite estimates. Credit: Michael Mishchenko, NASA
Sun-blocking aerosols around the world steadily declined (red line) since the 1991 eruption of Mount Pinatubo, according to satellite estimates. Credit: Michael Mishchenko, NASA

Wild et al. using measurements over land report brightening since 1990.[27][9][28] and Pinker et al.[29] found that slight dimming continued over land while brightening occurred over the ocean.[30] Hence, over the land surface, Wild et al and Pinker et al disagree. A 2007 NASA sponsored satellite-based study sheds light on the puzzling observations by other scientists that the amount of sunlight reaching Earth's surface had been steadily declining in recent decades, suddenly started to rebound around 1990. This switch from a "global dimming" trend to a "brightening" trend happened just as global aerosol levels started to decline.[31][26] This article or section does not adequately cite its references or sources. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... This article is about the American space agency. ...


It is likely that at least some of this change, particularly over Europe, is due to decreases in pollution. Most governments of developed nations have done more to reduce aerosols released into the atmosphere, which helps reduce global dimming, than to reduce CO2 emissions. A developed country is a country that is technologically advanced and that enjoys a relatively high standard of living. ...


Sulfate aerosols have declined significantly since 1970 with the Clean Air Act in the United States and similar policies in Europe. The Clean Air Act was strengthened in 1977 and 1990. According to the EPA, from 1970 to 2005, total emissions of the six principal air pollutants, including PM’s, dropped by 53 percent in the US. In 1975, the masked effects of trapped greenhouse gases finally started to emerge and have dominated ever since.[32] This article or section does not adequately cite its references or sources. ...


The Baseline Surface Radiation Network (BSRN) has been collecting surface measurements. BSRN was started in the early 1990s and updated the archives in this time. Analysis of recent data reveals that the surface of the planet has brightened by about 4% in the past decade. The brightening trend is corroborated by other data, including satellite analyses. Categories: Possible copyright violations ...


Relationship to hydrological cycle

This figure shows the level of agreement between a climate model driven by five factors and the historical temperature record. The negative component identified as "sulfate" is associated with the aerosol emissions blamed for global dimming.
This figure shows the level of agreement between a climate model driven by five factors and the historical temperature record. The negative component identified as "sulfate" is associated with the aerosol emissions blamed for global dimming.
Further information: Hydrological cycle

Pollution produced by humans may be seriously weakening the Earth's water cycle - reducing rainfall and threatening fresh water supplies. A 2001 study by researchers at the Scripps Institution of Oceanography suggests that tiny particles of soot and other pollutants have a significant effect on the hydrological cycle. "The energy for the hydrological cycle comes from sunlight. As sunlight heats the ocean, water escapes into the atmosphere and falls out as rain. So as aerosols cut down sunlight by large amounts, they may be spinning down the hydrological cycle of the planet." according to prof. V. Ramanathan.[33] Image File history File links Climate_Change_Attribution. ... Image File history File links Climate_Change_Attribution. ... Climate models use quantitative methods to simulate the interactions of the atmosphere, oceans, land surface, and ice. ... The historical temperature record shows the fluctuations of the temperature of the atmosphere and the oceans throughout history, and in particular since 1850. ... The water cycle is known scientifically as the hydrologic cycle. ... The movement of water around, over, and through the Earth is called the water cycle. ...


Large scale changes in weather patterns may also have been caused by global dimming. Climate models speculatively suggest that this reduction in sunshine at the surface may have led to the failure of the monsoon in sub-Saharan Africa during the 1970s and 1980s, together with the associated famines such as the Sahel drought, caused by Northern hemisphere pollution cooling the Atlantic.[34] Because of this, the Tropical rain belt may not have risen to its northern latitudes, thus causing an absence of seasonal rains. This claim is not universally accepted and is very difficult to test. Climate models use quantitative methods to simulate the interactions of the atmosphere, oceans, land surface, and ice. ... Bold text[[ // [[Image:Media:Example. ... For other uses, see Sahara (disambiguation). ... A world map showing the continent of Africa Africa is the worlds second-largest and second most-populous continent, after Asia. ... <nowiki>Insert non-formatted text hereBold text</nowiki>A famine is a social and economic crisis that is commonly accompanied by widespread malnutrition, starvation, epidemic and increased mortality. ... The Sahel drought in 1970s and 1980s created a famine that killed a million people and afflicted more than 50 million. ... The Atlantic Ocean is Earths second-largest ocean, covering approximately one_fifth of its surface. ... The weather in the tropics is dominated by the tropical rain belt, which oscillates from the northern to the southern tropics over the course of the year. ...


It is also concluded that the imbalance between global dimming and global warming at the surface leads to weaker turbulent heat fluxes to the atmosphere. This means globally reduced evaporation and hence precipitation occur in a dimmer and warmer world, which could ultimately lead to a more humid atmosphere in which it rains less.[35]


A natural form of large scale environmental shading/dimming has been identified that affected the 2006 northern hemisphere hurricane season. The NASA study found that several major dust storms in June and July in the Sahara desert sent dust drifting over the Atlantic Ocean and through several effects caused cooling of the waters - and thus deadening the development of hurricanes.[36][37] Hurricane seaons can refer to : The Atlantic hurricane season The Pacific hurricane season This is a disambiguation page — a navigational aid which lists pages that might otherwise share the same title. ... This article is about the American space agency. ...

Relationship to Global Warming

Further information: Global warming

Some scientists now consider that the effects of global dimming have masked the effect of global warming to some extent and that resolving global dimming may therefore lead to increases in predictions of future temperature rise.[14] According to Beate Liepert, "We lived in a global warming plus a global dimming world and now we are taking out global dimming. So we end up with the global warming world, which will be much worse than we thought it will be, much hotter."[38] The magnitude of this masking effect is one of the central problems in climate change with significant implications for future climate changes and policy responses to global warming.[39] Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ... Global warming refers to the increase in the average temperature of the Earths near-surface air and oceans in recent decades and its projected continuation. ...


But it's much more complicated than an either warming or dimming issue. Global warming and global dimming are not mutually exclusive or contradictory. In a paper published March 8, 2005 in the American Geophysical Union's Geophysical Research Letters, a research team led by Anastasia Romanou of Columbia University's Department of Applied Physics and Mathematics, New York, also showed that the apparently opposing forces of global warming and global dimming can occur at the same time.[40] Global dimming interacts with global warming by blocking sunlight that would otherwise cause evaporation and the particulates bind to water droplets. Water vapor is one of the greenhouse gases. On the other hand, global dimming is affected by evaporation and rain. Rain has the effect of clearing out polluted skies.


Climatologists are stressing that the roots of both global dimming-causing pollutants and global warming-causing greenhouse gases have to be deal with together and soon.[41]


Possible use to mitigate global warming

Further information: Mitigation of global warming and Albedo

Some scientists have suggested using aerosols to stave off the effects of global warming as an emergency measure. Russian expert Mikhail Budyko understood this relationship very early on. In 1974, he suggested that if global warming became a problem, we could cool down the planet by burning sulfur in the stratosphere, which would create a haze.[42][43][44] According to Ramanathan (1988), an increase in planetary albedo of just 0.5 percent is sufficient to halve the effect of a CO2 doubling.[45] Global carbon dioxide emissions 1800–2000 Global average surface temperature 1850 to 2006 Mitigation of global warming involves taking actions aimed at reducing the extent of global warming. ... Albedo is the ratio of reflected to incident electromagnetic radiation. ... Albedo is the ratio of reflected to incident electromagnetic radiation. ...


However, we would still face many problems, such as:

  • Using sulfates causes environmental problems such as acid rain[46]
  • Using carbon black causes human health problems[46]
  • Dimming causes ecological problems such as changes in evaporation and rainfall patterns[46]
  • Droughts and/or increased rainfall cause problems for agriculture[46]
  • Aerosol has a relatively short lifetime

"Ideas that we should increase aerosol emissions to counteract global warming have been described as a 'Faustian bargain' because that would imply an ever increasing amount of emissions in order to match the accumulated greenhouse gas in the atmosphere, with ever increasing monetary and health costs."[47] In essence, the sources of both greenhouse gases and air particulates must be addressed. St. ...


See also

energy Portal

Image File history File links Portal. ... Variations in CO2, temperature and dust from the Vostok ice core over the last 450,000 years For current global climate change, see Global warming. ... Not to be confused with insulation. ... The Iris Hypothesis is a partially-discredited theory that suggested increased water vapor in the atmosphere would result in reduced cirrus clouds and thus more visible-length radiation leakage from Earths atmosphere. ... One computer simulation of conditions during the Snowball Earth period. ... 400 year history of sunspot numbers. ...

References

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  2. ^ Rasool, Ichtiaque, S. and Schneider, Stephen H. (July 1971). "Atmospheric Carbon Dioxide and Aerosols: Effects of Large Increases on Global Climate". Science 173 (3992): 138-141. DOI:10.1126/science.173.3992.138. 
  3. ^ Lockwood, John G. (1979). Causes of Climate, Lecture notes in mathematics 1358. New York: John Wiley & Sons, p. 162. 
  4. ^ Ohmura, A. and Lang, H. (June 1989). in Lenoble, J. and Geleyn, J.-F. (Eds): Secular variation of global radiation in Europe. In IRS '88: Current Problems in Atmospheric Radiation, A. Deepak Publ., Hampton, VA (in English). , Hampton, VA: Deepak Publ., (635) pp. 298-301. ISBN ISBN 978-0937194164. 
  5. ^ Russak, V. (1990). "Trends of solar radiation, cloudiness and atmospheric transparency during recent decades in Estonia". Tellus B 42 (2): p.206. DOI:10.1034/j.1600-0889.1990.t01-1-00006.x. 1990TellB..42..206R. 
  6. ^ Liepert, B. G. et al. (2004). "Can Aerosols spin down the water cycle in a warmer and moister world?". Geophysical Research Letters 31. DOI:10.1029/2003GL019060. 
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  16. ^ Guardian Unlimited - Science - Goodbye sunshine, Thursday December 18, 2003
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  18. ^ Liu B., Xu M., Henderson M. & Gong W. (2004). "A spatial analysis of pan evaporation trends in China, 1955-2000" (in English). Journal of Geophysical Research 109 (D15102). DOI:15110.11029/12004JD004511. 
  19. ^ Sington, David. "TV&Radio follow-up", BBC - Science & Nature - Horizon, January 15, 2005. 
  20. ^ Roderick, Michael L.; Leon D. Rotstayn, Graham D. Farquhar, Michael T. Hobbins (2007-09-13). "On the attribution of changing pan evaporation". Geophysical Research Letters 34 (L17403). DOI:10.1029/2007GL031166. 
  21. ^ Rotstayn L.D., Roderick M.L. & Farquhar G.D. (2006). "A simple pan-evaporation model for analysis of climate simulations: Evaluation over Australia.". Geophysical Research Letters 33 (L17715). DOI:10.1029/2006GL027114. 
  22. ^ a b Travis, David J. (2002). "Contrails reduce daily temperature range". Nature 418: 601. 
  23. ^ "Transported Black Carbon A Significant Player In Pacific Ocean Climate", Science Daily, 2007-03-15. 
  24. ^ J. Srinivasan et al. (2002). "Asian Brown Cloud – fact and fantasy.". Current Science 83 (5): pp. 586-592. 
  25. ^ Crichton's Thriller State of Fear: Separating Fact from Fiction. Retrieved on 2006-06-12.
  26. ^ a b "Global 'Sunscreen' Has Likely Thinned, Report NASA Scientists", NASA, 2007-03-15. 
  27. ^ Wild, M et al. (2005). "From Dimming to Brightening: Decadal Changes in Solar Radiation at Earth’s Surface". Science 308 (2005-05-06): pp. 847-850. DOI:10.1126/science.1103215. 
  28. ^ Wild, M., A. Ohmura, and K. Makowski (2007). "Impact of global dimming and brightening on global warming". Geophysical Research Letters 34 (L04702): pp.. DOI:10.1029/2006GL028031. 
  29. ^ Pinker, et al. (2005). "Do Satellites Detect Trends in Surface Solar Radiation?". Science 308 (6 May 2005): pp. 850-854. DOI:10.1126/science.1103159. 
  30. ^ Global Dimming may have a brighter future. Retrieved on 2006-06-12.
  31. ^ Richard A. Kerr (2007-03-16). "CLIMATE CHANGE: Is a Thinning Haze Unveiling the Real Global Warming?". 
  32. ^ Air Emissions Trends - Continued Progress Through 2005 (HTML) (English).
  33. ^ Cat Lazaroff (2007-12-07). Aerosol Pollution Could Drain Earth's Water Cycle.
  34. ^ Rotstayn and Lohmann (2002). "Tropical Rainfall Trends and the Indirect Aerosol Effect". Journal of Climate: pp. 2103–2116. 
  35. ^ Kostel, Ken and Oh, Clare. "Could Reducing Global Dimming Mean a Hotter, Dryer World?", Lamont-Doherty Earth Observatory News, 2006-04-14. Retrieved on 2006-06-12. 
  36. ^ "Study ties hurricanes to Sahara", United Press International, 2007-04-03. 
  37. ^ "Did Dust Bust the 2006 Hurricane Season Forecasts?", NASA, 2007-03-28. 
  38. ^ Global Dimming.
  39. ^ Andreae O. M., Jones C. D., Cox P. M. (2005-06-30). "Strong present-day aerosol cooling implies a hot future". Nature 435: pp. 1187 - 1190. 
  40. ^ Alpert, P., P. Kishcha, Y. J. Kaufman, and R. Schwarzbard (2005). "Global dimming or local dimming?: Effect of urbanization on sunlight availability". Geophys. Res. Lett. 32 (L17802). DOI:10.1029/2005GL023320. 
  41. ^ Anup Shah (January 15, 2005). Global Dimming.
  42. ^ Spencer Weart (July 2006). Aerosols: Effects of Haze and Cloud.
  43. ^ Crutzen, P. (August 2006). "Albedo enhancement by stratospheric sulfur injections: a contribution to resolve a policy dilemma?". Climatic Change 77 (3-4): pp. 211-220. DOI:10.1007/s10584-006-9101-y. 
  44. ^ Harshvardhan (06/1978). "Albedo enhancement and perturbation of radiation balance due to stratospheric aerosols". 1978aepr.rept.....H. 
  45. ^ Ramanathan, V. (1988-04-15). "The greenhouse theory of climate change: a test by an inadvertent global experiment" (in (English)). Science 240 (4850): pp. 293-299. 
  46. ^ a b c d Ramanathan, V. (2006). "Atmospheric Brown Clouds: Health, Climate and Agriculture Impacts". Pontifical Academy of Sciences Scripta Varia (Pontifica Academia Scientiarvm) 106 (Interactions Between Global Change and Human Health): pp. 47-60. 
  47. ^ RealClimate: Global Dimming? (2005-01-18). Retrieved on 2007-04-05.

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A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Geophysical Research Letters is one of the scientific magazines dedicated to specialized aspects of geophysics, geology, climate science, and related disciplines. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Part of a scientific laboratory at the University of Cologne. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 163rd day of the year (164th in leap years) in the Gregorian calendar. ... Journal of Climate is a publication of the American Meteorological Society. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 163rd day of the year (164th in leap years) in the Gregorian calendar. ... Front of UPI Headquarters, Washington, D.C. “UPI” redirects here. ... Geophysical Research Letters is one of the scientific magazines dedicated to specialized aspects of geophysics, geology, climate science, and related disciplines. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... The term climate change is used to refer to changes in the Earths global climate or regional climates. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 95th day of the year (96th in leap years) in the Gregorian calendar. ...

External links

Image File history File links WikiNews-Logo. ... Wikinews is a free-content news source and a project of the Wikimedia Foundation. ...

Bibliographies

  • Roderick, Michael. Global Dimming Bibliography (English).
  • Saunders, Alison. Global Dimming Bibliography (English).

Notable Web Pages

  • Global Dimming summary (English). BBC Horizon.
  • Liepert, Beate. Global Dimming (requires flash) (English).
  • Global Dimming - part 1 (English). Realclimate.org.
  • Global Dimming - part 2 (English). Realclimate.org.
  • Global Dimming may have a brighter future (English). Realclimate.org.
  • Veiling Our True Predicament: Global Dimming - Easy to Understand Primer on Global Dimming, also including BBC documentary on the subject.

Podcasts

  • Brown Cloud (mp3) (English). Ecoshock.

Q&A

  • BBC Global Dimming Q&A (English).

News Articles

  • Adam, David. "Goodbye Sunshine", The Guardian, 2003-12-18. (English) 
  • Chang, Kenneth. "Globe Grows Darker as Sunshine Diminishes 10% to 37%", The New York Times, 2004-05-13. (English) 
  • Appell, David. "The Darkening Earth Less sun at the Earth's surface complicates climate models", Scientific American, 2004-08-02. (English) 
  • Keen, Kip. "Dim Sun Global dimming? Global warming? What's with the globe, anyway?", Grist Magazine, 2004-09-22. (English) 
  • Sington, David. "Why the Sun seems to be 'dimming'", BBC News, 2005-01-13. (English) 
  • Onion, Amanda. "Are Skies Dimming Over Earth? Data Suggest Human Pollution Can Lead to Darker Days", ABC News, 2006-02-09. (English) 
  • "Transported Black Carbon A Significant Player In Pacific Ocean Climate", Science Daily, 2007-03-15. (English) 
  • "Global 'Sunscreen' Has Likely Thinned, Report NASA Scientists", NASA, 2007-03-15. (English) 

The Guardian is a British newspaper owned by the Guardian Media Group. ... The New York Times is a daily newspaper published in New York City and distributed internationally. ... Scientific American is a popular-science magazine, published (first weekly and later monthly) since August 28, 1845, making it the oldest continuously published magazine in the United States. ... Grist Magazine, Environmental News & Commentary (est. ... BBC News is the department within the BBC responsible for the corporations news-gathering and production of news programmes on BBC television, radio and online. ... ABC News Special Report ident, circa 2006 ABC News is a division of American television and radio network ABC, owned by The Walt Disney Company. ... Science Daily is an online news source. ... This article is about the American space agency. ...

Slide Decks

  • Atmospheric Aerosol and Air Pollution.

Television Programs

  • Report on another consequence of global warming: the dimming effect of clouds (English). BBC2 TV Horizon (2005-01-15).
  • Dimming The Sun (English). PBS WGBH Boston NOVA (2006-04-18).
  • BBC Horizon - Global Dimming - Google Video (english). BBC Horizon.

  Results from FactBites:
 
Global (1679 words)
Global Warming is characterised by an increase in average temperatures on a year-on-year basis.
Global Dimming is characterised by an decrease in average temperatures on a year-on-year basis.
The reason that Global Warming is accelerating is because we are reducing the amount of Particlate polution in the atmosphere, this is reducing the Global Dimming phenomena, the opposing force that has kept Global Warming in check.
Global Dimming (862 words)
Global dimming is a term describing the gradual reduction in the amount of global hemispherical irradiance (or total solar irradiance) at the Earth's surface since the 1950s.
Global dimming creates a cooling effect that has led scientists to underestimate the effect of greenhouse gases on global warming.
The rate of dimming varies around the world but is on average estimated at around 2–3% per decade, with a possibility that the trend reversed in the early 1990s.
  More results at FactBites »

 
 

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