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Foundations of Social Studies GEOGRAPHY CLIMATE Many people think that climate and weather is the same thing. They are not. Weather is the current atmospheric conditions for a short period of time; for example, rain. Weather occurs in every type of climate. Climate is the average course of weather conditions over a long period of time. People who study the climate are known as climatologists while those who specialize in the weather are known as meteorologists. Weather describes the local atmospheric conditions at a given time. It is usually referred to in terms of a few things. These include temperature, precipitation, cloudiness, windiness, and pressure. Weather can change from hour to hour, and even from minute to minute, as in the case of tornados and hurricanes. Climate, on the other hand, changes very slowly. Climate is the average of all the weather in a given place over time. For this reason, when you study climate, you are really studying the average weather of a place. While scientists are interested in both weather and climate, social scientists – like geographers, historians, and economists - are really much more interested in climate, or the average weather of a place. Climate Types The world’s climates are generally divided into one of five basic types. These types are determined by looking at the average precipitation and temperature (during the year) combined with when precipitation occurs. There is a sixth climate type which describes some unique areas of the world. The basic climate types can be further subdivided in order to account for specific seasonal and geographical characteristics. Tropical climates: High temperatures with large amounts of rainfall and warm temperatures year round. Found between the Tropic of Capricorn (30° south latitude) and Tropic of Cancer (30° north latitude). This is a region which sits like a wide belt around the equator. This belt is sometimes referred to as “the tropics.” Arid climates: Very little rain with high temperatures, but also will have large temperature ranges in a 24-hour period. This climate will usually be found between low to middle latitudes (30° to 45° north and south of the equator). Mid-latitude climates: These climates will have warm, dry summers and cool, wet winters. They will be found in the middle latitudes (around 45° north and south of the equator) and coastal areas near oceans. Continental climates: This type of climate will have lower or higher precipitation than other climates at the same latitude and seasonal temperatures vary widely – very cold winters and very hot summers. Continental climates will be found in the interiors of large land masses. High latitude climates: These cold climate areas will have permanent ice and tundra present. They will have only about four months of temperatures above freezing temperatures. They are called “high latitude” because they occur north and south of 60° latitude. These climates can be either wet or dry depending on their location on a continent. Highland climates: Will be found in mountain and high plateau regions of the world. Temperatures will change quickly with elevation; the higher you go, the cooler it gets. Average precipitation will also vary Copyright © 2013, Davis School District with elevation, from rain to deep snow pack. This is the 6th climate type and is unique because within a highland area can be found many different climates depending on the elevation. What Affects Climate? The most important thing to affect climate is distance from the equator. The closer to the equator you go, the warmer it gets. The closer to the poles you go, the colder it gets. But there are several other things which strongly affect climates. They are: prevailing winds, ocean currents, and mountains. Wind is nothing more than air moving across the surface of the Earth. Wind occurs when the earth is heated by sunlight unevenly. Warmer air rises and creates an area of low pressure while sinking cool air creates areas of high pressure. Air moves from areas of high to low pressure. This is wind. Wind’s role in weather and climate is the only way for moisture to be brought over a land mass. Prevailing winds may continually bring dry air or moist air to region. This has an important effect on climate. Ocean currents affect climate in the coastal lands along which they flow. Cold currents which flow from Polar Regions help keep the air cool. Warm currents flowing from the equator bring warmer temperatures to coastal regions. Having an ocean nearby is also important to providing moist air masses to fuel precipitation. The opposite side of this is that some places which are very far from the ocean have more extreme temperature shifts. These areas, in the centers of large continents, heat up and cool down much more quickly than coastal areas because land heats up and cools down more quickly than water. This is why we say that the ocean “moderates” the coastal climates. It prevents them from having the same severe temperature swings that we have in areas located in the interiors of continents. Mountains force winds to rise, which cools the air, causing moisture to condense in clouds into rain and snow. Most of this moisture will be released on the windward side of the mountain range. After precipitation is released, the air warms and winds become drier as they descend on the opposite side of mountain (leeward side) and produce little to no precipitation. Deserts are often located on the leeward sides of mountains. Climate Change Some people worry that the world’s climates are changing as a result of human activity. They believe that huge amounts of carbon dioxide and other gases which have been released into the atmosphere during the last century may cause the earth to gradually warm. These gases come from burning fossil fuels, deforestation, industrial processes, and some agricultural practices. They are called greenhouse gases because they act as a blanket around the planet, trapping heat in the atmosphere causing the earth to warm. Other people are not sure whether or not human activities are having an effect on the climate. They note that the planet has experienced many shifts in its climate which clearly had nothing to do with effects of man. The ice ages are a clear example. Changes in climate, they would argue, may be part of a much longer pattern over which we have little control or effect. Copyright © 2013, Davis School District