Continental climate
Continental climate is characterized by significant temperature variations between seasons, leading to hot summers and cold winters. This climate is predominantly found in the Northern Hemisphere and includes regions across North America, Europe, and parts of Asia. Cities like Chicago exemplify this climate type, where average temperatures hover around 10° Celsius but can swing to extremes, with substantial precipitation averaging around 84 centimeters annually. This precipitation primarily falls as rain in summer and snow in winter, contrasting with regions like Seattle, which experiences more consistent rainfall throughout the year.
The continental climate zone is crucial for global agriculture, serving as a significant breadbasket for crops like corn and wheat. This zone is further categorized into humid continental climates with varying summer lengths, which can influence agricultural productivity in the face of climate change. Climate models suggest potential outcomes such as increased rainfall leading to flooding and plant diseases or, conversely, longer growing seasons with warmer temperatures. Understanding these dynamics is vital, as shifts in this climate type may impact food security and necessitate adaptations in farming practices.
Subject Terms
Continental climate
Definition
Defining a climate is difficult. The accuracy of weather observations and the length of time over which these data have been recorded can seriously affect the statistical understanding of a climate. Additionally, having data to produce statistical averages is no assurance that a climate’s classification can accurately describe its conditions. Consider Chicago’s humid, continental climate: The average temperature of the city is near 10° Celsius, but the nature of the climate in the region lends itself to extremes. Chicago’s daily temperatures are usually either well above or well below the average.
The average precipitation in Chicago is about 84 centimeters per year. This is equal to the precipitation level in Seattle, which has a west coast marine climate. Precipitation in Seattle is mostly rain, however, while Chicago experiences a mix of rain and snow. Rain in Chicago falls mostly in the summer, during violent convective storms. Rain in Seattle continues through the year, with a slight increase during the winter. Seattle’s maritime influence moderates the tendency toward convective storms.
Continental climates are characterized by extreme temperatures, and they are unique in that they have a global Northern Hemispheric distribution. In fact, to understand the potential impact that climate change might have on a continental climate, one must first consider its unique geographic character. Humid continental climates are found in North America, Europe, and Asia. In North America, they bound on the humid, subtropical climates of the southern and southeastern United States, and they encompass all of the northeastern quarter of the country.
The North American continental climate extends northward into Canada at a line of latitude that marks the extent of viable agricultural production. It extends westward into southern portions of the Prairie Provinces of Canada and north of the middle-latitude, dry climates that prevail just east of the Rocky Mountains. In Europe, the humid continental climate begins directly east of the marine-climate boundaries, along the west coast of the continent. It stretches into Russia, Germany, southern Sweden, and Finland, and is also found in Romania and Poland. Parts of Asia are also included in this climate. Almost all of northern China, the northern part of Japan, and North Korea fall within the humid continental climate zone.
The Köppen classification system places these climates in a group of midlatitude climates. Such climates include the west coast marine climate, the middle latitude dry climate, the humid continental-warm (long) summer climate, and the humid continental-cool (short) summer climate. The term “continental” has significance from the standpoint of the climate’s paleoclimatic character. Continental climates exist presently in only the Northern Hemisphere as a result of the movement of tectonic plates, which have concentrated Earth’s landmass in the northern half of the globe. The Southern Hemisphere lacks a sufficient continental landmass to form a continental climate. The Southern Hemisphere is more ocean (71 percent) than land. Most important, this region is agriculturally productive. Many soils in the region result from in the recent Pleistocene, 2 million years ago.
Significance for Climate Change
The continental climate sustains a global breadbasket. The climate can be divided further by the growing regions of corn (maize) or wheat. An imaginary line running east through the southern half of South Dakota, and as far east as New England, defines the margin zones of the humid continental long (warm) summer climate (to the south of this line) and the humid continental short (cool) summer climate (to the north of it). A similar line divides the climate in Europe and Asia. Thus, global climatic change within this zone has the potential to affect world food supplies.
In a warming affecting the continental climate zone, ancillary problems for farming may emerge. Some models suggest that warming will increase annual precipitation. The humid continental climate averages 76 centimeters of precipitation per year, with snow being the predominant form of precipitation in the winter. Precipitation in this climate zone can vary from about 51 centimeters near drier areas to 127 centimeters near the oceans. An increase in precipitation in the continental climate zone could lead to increased flooding, noxious weeds, and plant diseases. In contrast, some suggest that warming would lead to a longer growing period and a shift of the temperature toward the north.
Conversely, in a global cooling scenario, the continental climate zone might experience shorter summers, and the temperature line between warm and cool summers could move south. Drier conditions and drought would prevail. The region might expect to see more rainfall relative to snowfall, as rain might continue farther into the winter months. The continental short (cool) summer climate zone is characterized by cyclonic storms in winter that can bring huge snowfalls.
During the summer, convectional storms, many of them severe with lightning, are normal in continental short (cool) summer climate zones. The temperature average during summer is 24° Celsius. During the winter, average temperatures fall below freezing, down to –12° to –11° Celsius. With the influence of cold northern air, it is not uncommon to experience temperature extremes well below –18° Celsius. With increasing temperatures, the possibility for a prolonged period of convective storms might exist. Dry-land crops, such as wheat, would need to be modified to accommodate warmer and moister conditions. More rainfall might increase erosion in already tenuous soils, especially in highly productive löess soils. New farming methods to accommodate these changes would have to be implemented.
Bibliography
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Critchfield, Howard J. General Climatology. Englewood Cliffs, N.J.: Prentice-Hall, 1998.
Hamm, Alexandra, et al. "Continentality Determines Warming or Cooling Impact of Heavy Rainfall Events or Permafrost." Nature Communications, vol. 14, no. 3578, 15 June 2023, doi.org/10.1038/s41467-023-39325-4. Accessed 19 Dec. 2024.