global dimming

The gradual reduction in the amount of sunlight reaching the earth's surface.
Example Citations:
People may be oblivious to so-called global dimming, which tends to occur during cloudy periods.
Shabtai Cohen, who works at the Vocani Centre in Israel, said: "The cloudy times are getting darker. If it's cloudy then it's darker, but when it's sunny things have not changed much." Experts say the impact of reduced solar radiance may be greater in overcast areas of the northern hemisphere, such as Britain and Europe.
— "Black Carbon Is Plunging The World Into Darkness," Western Daily Press, December 19, 2003
In 1985, a geography researcher called Atsumu Ohmura at the Swiss Federal Institute of Technology got the shock of his life. As part of his studies into climate and atmospheric radiation, Ohmura was checking levels of sunlight recorded around Europe when he made an astonishing discovery. It was too dark. Compared to similar measurements recorded by his predecessors in the 1960s, Ohmura's results suggested that levels of solar radiation striking the Earth's surface had declined by more than 10% in three decades. Sunshine, it seemed, was on the way out.
The finding went against all scientific thinking. By the mid-80s there was undeniable evidence that our planet was getting hotter, so the idea of reduced solar radiation — the Earth's only external source of heat — just didn't fit. And a massive 10% shift in only 30 years? Ohmura himself had a hard time accepting it. "I was shocked. The difference was so big that I just could not believe it," he says. Neither could anyone else. When Ohmura eventually published his discovery in 1989 the science world was distinctly unimpressed. "It was ignored," he says.
It turns out that Ohmura was the first to document a dramatic effect that scientists are now calling "global dimming". Records show that over the past 50 years the average amount of sunlight reaching the ground has gone down by almost 3% a decade.
— David Adam, "Earth is 20% darker, say experts," The Guardian (London, England), December 18, 2003
Earliest Citation:
A number of studies show that significant reductions in solar radiation reaching the Earth's surface have occurred during the past 50 years. ... Finally the steps needed to strengthen the evidence for global dimming, elucidate its causes and determine its agricultural consequences are outlined.
— Gerald Stanhill and Shabtai Cohen, "Global dimming: a review of the evidence for a widespread and significant reduction in global radiation with discussion of its probable causes and possible agricultural consequences," Agricultural and Forest Meteorology, April 19, 2001
Related Words:
Pinatubo option

New words. 2013.

Look at other dictionaries:

  • 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. The effect varies by location, but worldwide it has been… …   Wikipedia

  • Global Dimming — Die globale Verdunkelung ist eine gemessene allmähliche Verringerung der Intensität des Tageslichtes, das die Erdoberfläche erreicht. Seit den 1950er Jahren wurden von der Arktis bis zur Antarktis hunderte von Messstationen installiert, die die… …   Deutsch Wikipedia

  • global dimming — /gloʊbəl ˈdɪmɪŋ/ (say glohbuhl diming) noun the gradual reduction in the level of energy from the sun reaching the earth s surface as a result of reflection from increasing amounts of particulate matter, such as soot, dust, etc., in the… …   Australian English dictionary

  • global dimming — noun A worldwide decline, during the last few decades, of the intensity of the sunlight reaching the Earths surface, caused by particulate air pollution. Such dimming has a dampening effect on global warming …   Wiktionary

  • global dimming —   the term to describe the blocking and/or scattering of insolation by particulate matter in the atmosphere, both natural (e.g. volcanic ash) and due to human activity (e.g. burning coal) …   Geography glossary

  • Global warming controversy — refers to a variety of disputes, significantly more pronounced in the popular media than in the scientific literature,[1][2] regarding the nature, causes, and consequences of global warming. The disputed issues involve the causes of increased… …   Wikipedia

  • Global cooling — in general can refer to an overall cooling of the Earth. In this article it refers primarily to a conjecture during the 1970s of imminent cooling of the Earth s surface and atmosphere along with a posited commencement of glaciation. This… …   Wikipedia

  • Global warming — This article is about the change in climate Earth is currently experiencing. For general discussion of how Earth s climate can change, see Climate change …   Wikipedia

  • Global climate model — AGCM redirects here. For Italian competition regulator, see Autorità Garante della Concorrenza e del Mercato. Climate models are systems of differential equations based on the basic laws of physics, fluid motion, and chemistry. To “run” a model,… …   Wikipedia

  • global ecophagy — (gloh.bul EK.oh.fay.gee) n. The potential destruction of life caused by rampant nanotechnological machines that break down organic matter to use as raw materials for replicating themselves. Example Citation: They call it global ecophagy . That s… …   New words

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