Climatology (Encyclopedia of Environmental Issues, Revised Edition)
Since the dawn of civilization and perhaps even before, human beings have observed regional weather patterns and attempted to correlate them with other phenomena in order to project the patterns into the future, chiefly for agricultural purposes. At low latitudes, where drought is the chief concern, predictions focused on variability in rainfall, while in northerly climates latitudinal variation in temperature and the factors influencing yearly variations in temperature were more important.
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Climatology in History (Encyclopedia of Environmental Issues, Revised Edition)
Over the centuries, the perception of human influence over climate has shifted. Ancient civilizations credited ritual observances with the capacity to influence the weather and ascribed extreme weather events such as prolonged droughts to divine wrath at human wrongdoing. With the rise first of modern astronomy, which eliminated the superstition from generally valid astrological long-term weather prediction, and then of increasingly sophisticated worldwide measurement of atmospheric phenomena, educated people came to regard climate as something independent of human activity and not susceptible to modification, except perhaps on a very local or temporary level. The pendulum swung in the opposite direction with the growing recognition that the rapid release of large volumes of greenhouse gases into the atmosphere has produced a general warming trend.
Like meteorology, climatology as a systematic science dates from the middle of the nineteenth century and represents a response to the need by the British Empire and the United States to expand agricultural and economic systems originating in Western Europe to regions with more variable and extreme climates. Close study of droughts and famines in India led to the discovery of the Southern Oscillation (now known as El Niño/Southern Oscillation), a regular decadal fluctuation of pressure in the western Pacific that profoundly affects rainfall in India and elsewhere....
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Paleoclimatology (Encyclopedia of Environmental Issues, Revised Edition)
In order to understand long-term climate fluctuations and trends, climatologists must reconstruct temperatures and rainfall for periods and in geographical areas for which no actual measurements exist—from within the last century in the case of remote and undeveloped regions to hundreds of millions of years in the case of the “snowball earth” of the late Precambrian or the Permian-Triassic extinction event. The climatic events since the last ice age are of most interest in the assessment of the probable effects of human activities and how they might interact with abiotic forcing mechanisms.
On a regional level, vegetation, which can be reconstructed through pollen profiles in sediments or sedimentary rock, is a reliable indicator of climate. For a picture of global climate, scientists look at ice cores from Greenland and Antarctica, in which trapped air provides a snapshot of atmospheric conditions, including greenhouse gases and particulates, and isotope ratios reflect oceanic evaporation and photosynthesis.
Glacial geologic features provide a persistent legacy of cold conditions, and rapid deposition of deltas and lake sediments is a signature of high rainfall. Where isotope, geologic, and fossil evidence co-occur they present a consistent picture of paleoclimate, but the value of isotope ratios alone is open to question.
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Global Warming (Encyclopedia of Environmental Issues, Revised Edition)
Climatology enters into debates on environmental issues only if human actions are perceived as influencing climate. Until fairly recently this would have been mainly in connection with desertification due to overgrazing or forest destruction. Although these human activities undoubtedly play a part in increasing aridity in areas such as the Sahel of Africa, the most recent treatments of the subject place more emphasis on shifts in global weather patterns than on local misuse of resources.
Data gathered and correlated by climatologists firmly identified the trend toward global warming. A network of interconnected national and international agencies tracks the course of global warming in time and supplies the data to bodies concerned with implementing public policy. By monitoring all of the factors believed to influence global temperatures, climatologists can estimate the degree to which warming is caused by human activities and pinpoint which activities produce the largest effects. Despite all of the effort and expertise that go into accumulating and analyzing these data, the results are often inconclusive and open to interpretation; even when unequivocal, the data can become tools for policy makers whose principal aim may not be the preservation of a sustainable environment.
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Further Reading (Encyclopedia of Environmental Issues, Revised Edition)
Alverson, Keith D., Raymond S. Bradley, and Thomas F. Pedersen, eds. Paleoclimate, Global Change, and the Future. New York: Springer, 2003.
Bonan, Gordon B. Ecological Climatology: Concepts and Applications. New York: Cambridge University Press, 2002.
Leroux, Marcel. Global Warming: Myth or Reality? The Erring Ways of Climatology. New York: Springer, 2005.
Mayewsky, Paul, et al. “Holocene Climate Variability.” Quaternary Research 62 (2004): 243-255.
Oliver, John E., ed. Encyclopedia of World Climatology. New York: Springer, 2005.
Saltzman, Barry. Dynamical Paleoclimatology: Generalized Theory of Global Climate Change. San Diego, Calif.: Academic Press, 2002.
Thompson, Russell D., and Allen Perry, eds. Applied Climatology: Principles and Practice. New York: Routledge, 1997.
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Definition (Encyclopedia of Global Warming)
Climatology can be defined as the synthesis of weather studies over a time interval long enough to determine statistical properties. In other words, meteorology plus time equals climatology. Climatology differs from meteorology in that meteorology describes the atmospheric conditions at present, what are most often called “the weather.” Meteorology also involves forecasting the weather for the very near future. Climatology involves studying the weather and its trends over a long period of time. Usually, the study of climate is limited to a particular area and, rather than providing a short-term forecast, can give an idea of the broad meteorological parameters in the area at any given time. The climate of a specific area can vary from year to year, decade to decade, or even century to century, and climatologists track these trends. Climatologists often use a thirty-year average to determine the normal climate for an area based on average humidity, precipitation, sunshine, and temperature. Meteorologists concentrate on the short term, studying and predicting weather systems that last only a few weeks.
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Significance for Climate Change (Encyclopedia of Global Warming)
Climatologists study the climate, how it changes, and how those changes over time may affect the Earth, humans, and other forms of life. There are several different branches of climatology, such as paleoclimatology (reconstructing past climates by examining evidence such as ice cores or tree rings), paleotempestology (determining the frequency of hurricanes over thousands of years in order to understand their patterns), and historical climatology (focusing on climate changes that occurred on the Earth after humans appeared).
Climatologists study the way five different climate systems interact with one another. These systems include:
- Atmosphere: Atmospherethe gases that surround the Earth, including water vapor
- Biosphere: Biospherethe Earth’s ecosystems and all living organisms and dead organic matter on land and in water
- Cryosphere: Cryosphereany frozen water, such as floating ice, glaciers, permafrost, or snow
- Hydrosphere: Hydrosphereall liquid surfaces, such as lakes, oceans, rivers, as well as underground water
- Lithosphere: Lithospherethe solid parts of the Earth
Based on the interactions between and among these systems and the way weather is created by them, climatologists are able to predict the changes in these systems that will affect the climate and, to a certain extent, what kinds of changes in the climate may occur as a result of these...
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Further Reading (Encyclopedia of Global Warming)
Barry, R. G. Synoptic and Dynamic Climatology. New York: Routledge, 2001. Discusses climate dynamics and mechanisms and synoptic-scale weather systems.
Bonan, G. Ecological Climatology: Concepts and Applications. New York: Cambridge University Press, 2008. Focuses on interactions between the climate and ecosystems; reviews basic meteorological, hydrological, and ecological concepts.
Critchfield, H. J. General Climatology. Englewood Cliffs, N.J.: Prentice Hall, 1998. Discusses all aspects of weather and climate as well as past and possible future climate changes. Includes charts, graphs, and black-and-white photos.
Hartmann, D. L. Global Physical Climatology. San Diego, Calif.: Academic Press, 1994. A textbook approach to physical climatology including the climate system. Includes a comprehensive index.
Oliver, J. E., ed. The Encyclopedia of World Climatology. New York: Springer, 2005. Discusses the subfields of climatology. Includes graphs, charts, drawings, and citations to other important climatology works.
Oliver, J. E., and J. J. Hidore. Climatology: An Atmospheric Science. 2d ed. Upper Saddle River, N.J.: Prentice Hall, 2002. Discusses why recent climate changes have occurred and explains the science behind those changes. Describes how basic processes operate in the atmosphere.
Perry, A. Applied Climatology: Principles and...
(The entire section is 272 words.)