CLIMATE

CLIMATE is the average weather conditions of a region, or the weather patterns that occur over many years. It is usually described by the average monthly and yearly temperatures and the average amount of PRECIPITATION (rainfall, snow, sleet etc.) To give a true perspective of a region’s climate, several factors must be investigated that affect the temperature and precipitation.

The Earth’s climate system is made up of a complex number of interacting parts. The prime mover of the system is the sun, whose energy heats the Earth. This causes circulation within the air and the oceans and drives the evaporation and precipitation processes of the water cycle. In addition to the atmosphere and the oceans, the climate system includes fresh water, plants and animals, ice and snow, land masses and even the Earth’s crust.

The first factor that affects climate is LATITUDE. This is the distance from the equator. This has a major influence on the climate of a region because it determines the amount of solar energy received by and the prevailing wind patterns of the region. How much solar energy a region receives depends on the angle at which the rays strike the Earth and the number of hours of daylight. At the equator, the sun’s rays always strike the earth at almost a 90 degree angle. In this region, day and night are each about twelve hours long throughout the year. This results in steady high temperatures year-round and a yearly temperature range of only 3 or 4^oC in most areas. There are no summers or winters, only dry or rainy seasons.

The farther toward the Polar Regions the lower the angle the sun’s rays strike the Earth, and the solar energy is spread over a wider area. Yearly temperature averages get correspondingly lower, with the largest annual temperature range in the Polar Regions.

The distance a region is from the equator also determines global wind patterns. Winds greatly affect weather conditions of humidity, amount and type of precipitation, temperature and cloud cover. These minor factors have also a great affect on a region’s climate.

The second major factor affecting climate is HEAT ABSORPTION AND RELEASE.

Land and water absorb and release heat at different rates than water does. Land also cools faster than water does. Water movements like waves and currents continuously replace warm surface water with cooler water from the ocean depths. This has a steadying influence on the temperature of the atmosphere. The ocean stores solar energy in the summer and releases it into the air in the winter. Ocean currents carry the warmth of tropical waters towards the Polar Regions bringing more balance to these regions. Average temperatures of land and water regions even in the same latitude vary due to differences in the loss of heat through evaporation. Water surfaces are much more affected by evaporation than are land surfaces.

The third major factor affecting climate is TOPOGRAPHY, or the shape of the land. The higher the ALTITUDE or height above sea level the lower the average temperature. So snow can be seen on the tops of mountains that may border desert areas. In fact, those dry desert areas are produced when air passing over a mountain range loses its moisture as it rises and cools.

A weather phenomenon that affects the climate throughout the world is called El Nino. It is a part of the interaction of the tropical waters of the Pacific Ocean and the earth’s atmosphere. An El Nino usually occurs approximately every two to seven years, and lasts about eighteen months. It is often followed by an opposite pattern called La Nina. The term El Nino, a Spanish word for “the boy”, originally referred to a current of warm water that flowed southward along the coast of Ecuador and Peru. This occurs near Christmas Eve, so El Nino is a reference to the Christ child. Periodically, this warm current is abnormally strong and lasts for an extra long period of time. This current is accompanied by changes in precipitation and the winds across the entire tropical Pacific region. It begins with a weakening or even a reversal of the trade winds that usually push warm water toward the western Pacific Ocean. The warm water flows eastward instead to the cool coastal waters of the west coast of South America. The nutrient-rich cold water cannot rise to the surface so plant life and fish populations sharply decrease. This can bring devastation to the fishing industry of the coastal waters of Ecuador and Peru. These higher ocean temperatures also affect atmospheric temperatures and cause increased cloud cover and heavier than normal rainfall on the west coast of South America. This, in turn, causes the climate in Indonesia and other Southeast Asian nations to be unusually dry even to the point of drought conditions. El Nino causes a ripple effect in the weather patterns that may affect up to 70% of the Earth’s weather.

La Nina, the Spanish word for “the girl”, generally affects climate in an opposite way of El Nino. For instance, waters of the western Pacific are warmer than normal causing monsoon rains, and the waters off of the west coast of South America are cooler than normal. Both El Nino and La Nina conditions can disrupt the weather, climate, and lives of millions of people worldwide.

The climate of a particular region has a direct impact on the people who live there. The following videos discuss the difference between weather and climate and identifies the six major climate regions.

What is Climate? (01:18)

Climate Regions (02:06)

Five Factors that Affect Climate (05:23)

Climate Changes (04:05)

How Climate Affects Living Patterns (02:25)

The Water Cycle (06:05)