Chapter 14 Climate

“Want to trade places?”

What is Climate?

  Climate is the composite or generally prevailing weather conditions of a region, as temperature, air pressure, humidity, precipitation, sunshine, cloudiness, and winds, throughout the year, averaged over a series of years. In other words Climate is determined by a series of

weather data collections, of a specific region, over a period of time ( at least 30 years)

-How is climate different than weather???



Weather – the state of the atmosphere at any given time or place (DAILY DATA COLLECTION)

CLIMATE

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Koeppen’s Climate Classification System

In 1920, Wladimir Peter Köppen developed a classification system for climates based only on precipitations and temperatures.

The world is divided into 5 major climatic zones based upon this classification system.

Koeppen System

Chart Layout

 http://geography.about.com/library/weekly /aa011700b.htm

What Determines Climate?

 

Two of the most important factors determining an area's climate are air temperature and precipitation.

Example: Located in northern South America, Venezuela has a tropical climate.  Why is this country considered Tropical?

-Tropical climates have an annual rainfall of 250 cm or more and an average temperature of 80˚F.

VENEZUELA

6 Things that Affect Climate

1.

2.

3.

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Latitude – distance North or South of the Equator

Higher latitudes, colder climate ◦

Elevation – distance above sea level

Higher elevation, colder climate ◦

Topography – the lay of the land

Mountains play an important role in the amount of precipitation that falls on an area

6 Things that Affect Climate (cont.)

4.

5.

6.

Water Bodies – lakes and oceans affect the temperature of the air above them Atmospheric circulation – global winds distribute heat and moisture around Earth

◦

Vegetation – plants affect the amount of the sun’s energy is absorbed and how quickly the energy is released

Transpiration – releases water vapor into the air

Natural Processes Change Climate

1.

2.

3.

4.

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Volcanic Eruptions

Volcanic ash and dust reflect sunlight back into space (causes the Earth’s surface to cool) ◦

Ocean Circulation – can result short term climate fluctuations

El nino and La nina

Solar Activity – variations in solar activity can cause short term climatic change

◦

Changes in the Earth’s motion –

tilt, precession, orbit

Human Impact on Climate Changes

 

The Greenhouse Effect – a natural warming of both the Earth’s lower atmosphere and surface

◦ The sun’s light goes through the Earth’s atmosphere and heats up the land ◦ The land then radiates the heat back into the atmosphere ◦ The lower atmosphere traps the heat making it warmer

Allows humans to live on Earth

Historic CO

2

Emissions

Human impact on the Greenhouse Effect



Carbon Dioxide levels have increased in our atmosphere since 1850

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The industrial revolution

◦ ◦  

Burning fossil fuels increase the amount of CO 2 in the atmosphere Cutting trees also increases the amount of CO 2 in the atmosphere

CO 2 released when plants are burned Plants use CO 2 to make food

Global Warming



Global temperatures have increased due to more CO 2 and other greenhouse gases in the atmosphere

◦ Earth’s surface temperature has increased 0.6°C during the 20 th century ◦ Predicted: by the year 2100 surface temperatures will increase by 1.4°C to 5.8°C   Will lead to sea ice melting and a rise in sea levels Sea ice reflects sunlight and will increase the amount of heat in the atmosphere

Global Warming

 The hotter the temperatures, the more the climate changes, leading to natural disasters all over the world, from wild fires and flooding to long-term drought. Sea levels are rising from melting ice sheets. Warmer air and ocean

temperatures are endangering many

animal and plant species unable to adapt to such rapid changes.

CFC’s-Chlorofluorocarbons

    

Compound consisting of chlorine, fluorine, and carbon

CFCs are very stable in the troposphere.

They move to the stratosphere and are broken down by strong ultraviolet (UV) light, where they release chlorine atoms that then deplete the ozone layer .

CFCs are widely used as coolants in refrigeration and air conditioners, as solvents in cleaners, particularly for electronic circuit boards, as a blowing agents in the production of foam (for example fire extinguishers), and as propellants in aerosols.

Indeed, much of the modern lifestyle of the second half of the 20 th into the 21 st century had been made possible by the use of CFCs.

Ice Age and El Nino (Climatic events) •

Ice Ages occur when Earth’s climate experiences an extreme drop in temperature.

The Facts:

•

There were about 11 different ice ages.

•

The ice ages were during the earth's 4.6 billion years of history.

•

The last ice age was called "The Great Ice Age" and was 11,000 years ago.

•

During the "Great Ice Age" over a third of the earth was covered in ice. During the ice age the air had less carbon dioxide in it.

Ice Age Continued

• •

Right now we are living in a mini ice age.

There are two explanations of why the ice ages might have occurred: 1.The temperatures were much colder so it never rained, only snowed. 2. The earth changed its tilt away from the sun.

El Nino and La Nina

 

El Nino-Abnormal warm ocean water temperatures that occasionally develops off the western coast of South America and can cause climatic changes across the Pacific Ocean. Brings warm temps and rain La Nina- Opposite of El Nino it brings colder temperatures along the equator.According to scientists, La Niña cycles generally create a more active hurricane season in the Atlantic