Factors That Affect Climate 5: Climate

Difference

Because of the effect of latitude, less solar energy per unit of area is transferred into the atmosphere in the polar regions than in the tropics. This difference in energy affects weather and climate from the equator to the poles. Differences in energy lead to the pressure differences that produce winds. Differences in energy affect evaporation rates and the formation of clouds, air masses, and storms. Over time, energy differences on a global scale also determine climate.

City A has a colder climate than City B. Which is the most likely reason for this difference?

City A has a higher elevation than City B.

Introduction

Climate includes not only the average weather conditions of an area, but also any variations from those norms. In this lesson, you will learn that climate involves more than just the atmosphere. Powered by the sun, the climate system is a complex exchange of energy and moisture among Earth's different spheres, all of which are shown in the figure.

Elevation

Elevation, or height above sea level, affects an area's climate. Air temperature decreases with elevation by an average of about 6.5°C every 1000 meters. The higher the elevation is, the colder the climate. The elevation of an area also determines the amount of precipitation it receives.

Global Circulation

Energy transfer between the world's oceans and its atmosphere helps to counteract the uneven distribution of solar radiation across the globe. It is also the major driver of weather and climate. In the tropics, the air is warmed by contact with warm ocean water. Warm air expands, becomes less dense, and rises. As air rises, it cools and the water vapor it carries condenses into liquid water, which falls to the surface as precipitation. The higher into the atmosphere the air goes, the cooler it gets. Cool air contracts, becomes denser, and sinks. This circulation keeps the atmosphere in constant motion.

Atmospheric Circulation

Global winds are another factor that influences climate because they distribute heat and moisture around Earth. Winds constantly move warm air toward the poles and cool air toward the equator. The low-pressure zones at the equator and in the middle latitudes lead to the formation of clouds that drop precipitation as rain or snow.

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Polar Zones

In the polar zones, which are between 66.5° north and south latitudes and the poles, the energy strikes at an even smaller angle, causing the light and heat to spread out over an even larger area. Therefore, the polar regions experience very cold temperatures, even in the summer.

Temperature Zones

In the temperate zones, which are between about 23.5° and 66.5° north and south of the equator, the sun's energy strikes Earth at a smaller angle than near the equator. This causes solar energy to be spread out over a larger area. In addition, the length of daylight in the summer is much greater than in the winter. As a result, temperate zones have hot summers and rather cold winters.

Water Bodies

Large bodies of water such as lakes and oceans have an important effect on the temperature of an area because the temperature of the water body influences the temperature of the air above it. Places downwind of a large body of water generally have cooler summers and milder winters than places at the same latitude that are farther inland.

Latitude

Latitude is the distance north or south of the equator. As latitude increases, the average intensity of solar energy decreases. Near the equator, the sun's energy strikes the planet at nearly right angles. Therefore, in this region, between about 23.5° north (Tropic of Cancer) and 23.5° south (Tropic of Capricorn) of the equator, the sun's rays are most intense. This region is called the tropical zones, or the tropics. Temperatures in the tropical zones are generally warm year-round.

Meteors and Asteroids

Most meteors and asteroids burn up in the Earth's atmosphere. But those that make it to the surface can vaporize the land or water they hit. Depending on the size of the meteorite, the amount of dust or water vapor added to the air can be significant. Meteorite impacts can also set off forest fires that can burn thousands of acres of wood. Like other types of fuel, wood adds carbon dioxide to the air when it is burned. Today, most meteorites are small pieces of rock. However, there have been many large meteorites that have struck Earth in the past, which may have influenced the climate.

Climate Change Over Time

The geosphere may seem like a permanent, unchangeable Earth system. However, the geosphere is constantly changing. It just changes very slowly. Changes in the geosphere can have profound effects on the other subsystems of Earth. Study the changes in the configurations of the continental plates shown in the figure. Consider how the following scenarios could have affected the biosphere, hydrosphere, and/or atmosphere:

Topography

Topographic features such as mountains play an important role in the amount of precipitation that falls over an area. As shown in the figure, humid air on the windward side of a mountain moves up the mountain's slopes and eventually cools to form clouds. Heavy precipitation often falls from these clouds. By the time air reaches the leeward side of a mountain, much of the moisture is lost. This dry area is called a rain shadow. Rain shadows can extend for hundreds of kilometers downwind of a mountain range

Which best describes the relationship between vegetation and climate?

Vegetation and climate affect one another.

Vegetation

Vegetation can affect both temperature and the precipitation patterns in an area. Vegetation influences how much of the sun's energy is absorbed and how quickly this energy is released. This affects temperature. During a process called transpiration, plants release water vapor from their leaves into the air. So, transpiration influences precipitation. Studies also indicate that some vegetation releases particles that act as cloud seeds. This increase in particles such as pollen promotes the formation of clouds, which also influences regional precipitation patterns.

How does vegetation affect climate?

Vegetation influences how much of the sun's energy is absorbed and released. Plants also release water vapor, which influences regional precipitation patterns.

Volcanoes

Volcanic eruptions and the collision of large meteorites with Earth's surface can have impacts on global climates, as well. Volcanoes emit dust and gases when they erupt. Ash from volcanic eruptions can circle the Earth in a matter of weeks. Small particles of dust in the air decrease the amount of sunlight that can reach the surface. In 1991, Mount Pintbo in the Philippines erupted with an ash cloud that was several hundred miles across. The ash from this eruption was carried around the Earth and helped to lower average global temperatures for a year. Many of the gases spewed during volcanic eruptions are greenhouse gases. These gases include carbon dioxide, sulfur dioxide, and water vapor. Scientists estimate that volcanic eruptions around the world add about 100 million tons of greenhouse gases to the atmosphere each year. For comparison, human activities pump approximately 40 billion tons of greenhouse gas into the atmosphere annually.

How can volcanic eruptions decrease global temperatures?

Volcanic eruptions emit fine dust particles.

Water and The Ocean

Water in the oceans is also in constant motion. Ocean currents act like conveyor belts that move warm water from the equator toward the poles and cold water from the poles toward the equator. When water is heated, it evaporates and turns to water vapor. Evaporation increases the temperature and the humidity of the air above and atmospheric circulation begins. Rising air creates low pressure at the surface level. Conversely, sinking air creates high pressure. Air naturally flows from areas of high pressure to areas of low pressure. This natural flow creates wind, and winds are the drivers of currents on the surface of the oceans. Atmospheric and oceanic circulations are the primary mechanism for redistributing heat on Earth. Without this circulation, temperatures at the equator would be much hotter than they are currently and the poles would be more frigid.

Changes in the latitudes of continents

could change the flow of water (hydrosphere) as well as influence how much ice freezes or melts, which would change the composition of the atmosphere as evaporation rates speed up or slow down. A change in latitude would also affect the animals and plants that lived on the continents (biosphere). For example, there are large coal deposits in Antarctica. Therefore, Antarctica was once much closer to the equator than it is today.

As latitude increases, climates tend to become cooler because of the _____.

decreasing intensity of solar rays

Land bridges

were built and destroyed, creating new or destroying old migration paths (biosphere) and may have changed the flow of water (hydrosphere), which would have changed the composition of the atmosphere.

Ocean pathways

were opened and closed, which may have changed ocean currents (hydrosphere), which would affect weather and climate (atmosphere), which could affect plants and animals (biosphere).

Large mountain belts

were produced when plates collided, which could have produced barriers animals could no longer get around (biosphere). This could also have changed the flow of water (hydrosphere) and produced changes in weather and climate (atmosphere), which would also affect the biosphere.

The west coast of the United States has a milder climate than places farther inland. What causes this difference?

winds that blow from the Pacific Ocean to the west coast

Changes in the shape of ocean basins

would have caused sea level rise or fall, which would affect the biosphere.