8.4: Components of Earth’s Climate System
pg. 330
The Climate System
The Earth’s climate system makes Earth unique among the planets.
The global temperature and living conditions are maintained,
allowing life to exist.
There are four main components of the Earth’s climate system; the
atmosphere, the hydrosphere, the lithosphere, and living things.
The Atmosphere
The Earth is covered in a layer of
gases, which make up the
atmosphere (hydrogen – 78%,
oxygen – 21%, carbon dioxide,
argon, helium, water vapour, and
ozone - 1%), and reaches 100 km
above the Earth’s surface.
The atmosphere absorbs, reflects
and radiates the Sun’s energy, as it
travels to the Earth’s surface.
Ozone in the Stratosphere
The Sun is needed for life on earth, yet the Sun’s energy can be
dangerous to life also. The Sun causes damage, such as; sunburn,
and skin cancer, to living things. The Ozone layer (O3), in the
atmosphere is responsible for protecting organisms from this
damage.
The ozone layer absorbs the ultraviolet radiation from the Sun,
preventing it from reaching the Earth’s surface.
In the 1970’s, scientists determined the ozone layer over Antarctica
was thinning, in 1990 the same thing was occurring over the Artic.
These were none as ozone holes in the atmosphere.
Chlorofluorocarbons (CFC’s) were determined to be the cause of
this depletion. These CFC’s came from the refrigerants that were
found in our refrigerators and cooling systems. These chemicals
entered the atmosphere and reacted with the ozone layer,
destroying it.
It has been determined that it will take 50 years before all the
CFC’s to breakdown and the ozone layer to recover.
Ozone in the Troposphere
Ozone found on the surface is not protective, but actually
dangerous, toxic and corrosive, to living things and damages
buildings.
The UV radiation converts the car exhaust to produce toxic
chemicals and surface ozone. These chemicals form photochemical
smog. The ozone released at the surface level does not move up
into the stratosphere, therefore it is not helpful.
The Hydrosphere
Hydrosphere – is the part of the climate system that includes all
water on and around Earth.
Hydrosphere includes liquid water, water vapour, and ice. Water
absorbs energy from the warm air and the Sun, and releases energy
back into the atmosphere.
The Water Cycle
The water cycle is very important to the climate system. Energy
absorbed by the water, causes it to evaporate from the lakes, rivers,
and oceans. This process causes a cooling affect in the surrounding
area. When the water vapour condenses (precipitation), energy is
released, warming the surroundings.
Large Bodies of Water and Climate Zones
Large bodies of water will have an effect on the climate of nearby
regions. The water absorbs and stores more thermal energy than
land. Regions near large bodies of water have a tendency to be
cooler than inland locations during the summer. This is because of
the amount of energy required to evaporate water into water
vapour.
During the winter the reverse occurs, the water mass releases
stored energy back into the atmosphere. Therefore the region is
slightly warmer than inland locations.
A large body of water takes a long
time to warm up or cool down.
Regions near an ocean or lake
tend to be cooler in summer
and warmer in the fall.
Air passing over unfrozen water in
winter absorbs water vapour.
Once the air reaches land, the
water vapour condenses as snow.
Regions downwind from a
large body of water have more
snowfall in winter.
Ice and the Climate System
2% of the Earth’s surface is covered by ice. Most of the ice is
located at the two poles. Ice known as Sea ice (Pack Ice) is usually
a few metres thick, while ice stretching over land can be several
kilometres thick.
Permanent ice is also found in Glaciers, on Mountain tops, and in
the permafrost. The ice surfaces reflect a great deal of energy back
into the atmosphere, keeping the region cold.
Lithosphere
Lithosphere – is the part of the climate system made up of the solid
rock, soil, and minerals of Earth’s crust and extends under the
oceans as well.
The lithosphere absorbed the Sun’s energy and converts it to
thermal energy, and releases it back as lower-energy infrared
radiation.
As clouds are blown up over
mountains, they lose moisture as
rain on the windward side.
The leeward side of a mountain
receives little rain (the rain shadow
effect).
As air rises, it expands and cools
down.
At high altitudes, the air is cooler
than at low altitudes.
Land Formations and Climate Zones
Land forms and mountains affect the climate zones. As clouds
move up and over mountains, they cool and water vapour
condenses, precipitation occurs on the windward side. As the
clouds move across to the leeward side there is very little rain.
Altitude and Climate Zones
The air pressure is less at higher altitudes then at the surface,
therefore air at the surface will rise and expand and cools down.
Living Things
All organisms are part of the climate system. Plants and animals
change the amounts of gases in the atmosphere. Plants perform
photosynthesis, and take in carbon dioxide and release oxygen
back into the atmosphere.
All organisms, including plants, perform cellular respiration; they
take in oxygen and release carbon dioxide back into the
atmosphere. Some organism, such as; cows and sheep produce
methane gas as they digest food.
Waste gases, carbon dioxide and methane; absorb infrared
radiation from the Earth. An increase in these gases can lead to
atmospheric changes (Greenhouse Effect).
Check Your Learning, questions 1 – 7, pg. 335