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4-1 The Role of Climate
Photo Credit: ©Michael Fogden/DRK PHOTO
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What Is Climate?
What Is Climate?
Weather is the day-to-day condition of Earth's atmosphere at a particular time and place.
Climate refers to the average year-after-year conditions of temperature and precipitation in a particular region.
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What Is Climate?
Climate is caused by:
trapping of heat by the atmosphere
latitude
transport of heat by winds and ocean currents
amount of precipitation
shape and elevation of landmasses
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The Greenhouse Effect
How does the greenhouse effect maintain the biosphere's temperature range?
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The Greenhouse Effect
The Greenhouse Effect
Atmospheric gases that trap the heat energy of sunlight and maintain Earth's temperature range include:
carbon dioxide
methane
water vapor
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The Greenhouse Effect
Sunlight
Some heat escapes into space
The natural situation in which heat is retained in Earth’s atmosphere by this layer of gases is called the greenhouse effect.
Greenhouse gases trap some heat
Greenhouse gases trap some heat
Carbon dioxide, water vapor, and several other gases in the atmosphere allow solar radiation to enter the biosphere but slow down the loss of heat to space. These greenhouse gases cause the greenhouse effect, which helps maintain Earth’s temperature range.
Atmosphere
Earth’s Surface
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Greenhouse effect
Step 1: Solar radiation reaches the Earth's atmosphere - some of this is reflected back into space.
Step 2: The rest of the sun's energy is absorbed by the land and the oceans, heating the Earth.
Step 3: Heat radiates from Earth towards space.
Step 4: Some of this heat is trapped by greenhouse gases in the atmosphere, keeping the Earth warm enough to sustain life.
Step 5: Human activities such as burning fossil fuels, agriculture and land clearing are increasing the amount of greenhouse gases released into the atmosphere.
Step 6: This is trapping extra heat, and causing the Earth's temperature to rise.
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8. The Effect of Latitude on Climate
Solar radiation strikes different parts of Earth’s surface at an angle that varies throughout the year.
At the equator, energy from the sun strikes Earth almost directly.
At the North and South Poles, the sun’s rays strike Earth’s surface at a lower angle.
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9. The Effect of Latitude on Climate
What are Earth's three main climate zones?
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10. The Effect of Latitude on Climate
As a result of differences in latitude and thus the angle of heating, Earth has three main climate zones:
polar,
temperate, and
tropical
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11. The Effect of Latitude on Climate
Earth’s Main Climate Zones
90°N North Pole
Sunlight
Polar
66.5°N
Arctic Circle
Temperate
Sunlight
Tropic of Cancer
23.5°N
Equator
Most direct sunlight 0°
Tropical
Tropic of Capricorn
23.5°S
Earth has three main climate zones. These climate zones are caused by the unequal heating of Earth's surface. Near the equator, energy from the sun strikes Earth almost directly. Near the poles, the sun's rays strike Earth's surface at a lower angle. The same amount of solar energy is spread out over a larger area, heating the surface less than at the equator.
Sunlight
Temperate
Antarctic Circle
66.5°S
Sunlight
Polar
90°S South Pole
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12. The Effect of Latitude on Climate
The polar zones are cold areas where the sun's rays strike Earth at a very low angle.
Polar zones are located in the areas around the North and South poles, between 66.5° and 90° North and South latitudes.
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13. The Effect of Latitude on Climate
The temperate zones sit between the polar zones and the tropics.
Temperate zones are more affected by the changing angle of the sun over the course of a year.
As a result, the climate in these zones ranges from hot to cold, depending on the season.
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14. The Effect of Latitude on Climate
The tropical zone, or tropics, is near the equator, between 23.5° North and 23.5° South latitudes.
The tropics receive direct or nearly direct sunlight year-round, making the climate almost always warm.
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15. Earth’s tilt on its axis plays a role in seasonal change.
Solar heating causes movements in both water and air.
wind
ocean currents
Earth’s rotation also has effects on the winds and currents

16. Heat Transport in the Biosphere
Unequal heating of Earth’s surface drives winds and ocean currents, which transport heat throughout the biosphere.
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17. Heat Transport in the Biosphere
Earth’s Winds
WINDS
Polar Easterlies
66.5°N
Westerlies
23.5°N
Northeast Trade Winds 0°
Equator
23.5°S
Southeast Trade Winds
Earth's winds and ocean currents interact to help produce Earth's climates. The curved paths of some currents and winds are the result of Earth's rotation.
Westerlies
66.5°S
Polar
Easterlies
Prevailing winds
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18. Heat Transport in the Biosphere
Similar patterns of heating and cooling occur in Earth’s oceans. Cold water near the poles sinks, then flows parallel to the ocean bottom, and rises in warmer regions.
Water is also moved at the surface by winds.
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19. Heat Transport in the Biosphere
Ocean Currents
OCEAN CURRENTS
66.5°N
23.5°N
Equator 0°
23.5°S
Earth's winds and ocean currents interact to help produce Earth's climates. The curved paths of some currents and winds are the result of Earth's rotation.
66.5°S
Warm currents
Cold currents
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20. Heat Transport in the Biosphere
The movement of the water creates ocean currents, which transport heat energy throughout the biosphere.
Surface ocean currents warm or cool the air above them, affecting the weather and climate of nearby landmasses.
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21. Landmasses shape inland climates.
larger changes in temperatures
less precipitation
Oceans shape coastal climates.
smaller changes in temperatures
higher humidity
more precipitation

22. Mountains have an effect on climate.
Precipitation occurs on the side of the mountain facing the wind.
On the downwind side, drier and cooler air produce a rain shadow.
A rain shadow is an area of decreased precipitation.
western slope
eastern slope

23. Many organisms survive in a specific climate due to their adaptations.

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4-1
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The Earth’s polar zones are cold because
they are never heated by the sun.
at the poles, the sun's rays are at a very low angle.
the greenhouse effect does not occur at the poles.
heat is transported from the poles to the equator.
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The upward movement of warm air and the downward movement of cool air creates
upwellings.
air currents.
ocean currents.
the greenhouse effect.
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Earth's temperature range is maintained by
the greenhouse effect.
climate zones.
ocean currents and winds.
latitude differences.
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Variation of temperature in the temperate zone is due primarily to
air and ocean currents.
the greenhouse effect.
variation in the sun’s energy production.
latitude and season.
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The tropical zone is warm all year long because
the sun’s angle changes the most in that part of Earth.
ocean water is warmest near the equator.
it receives direct or nearly direct sunlight year-round.
landmasses in the tropic latitudes hold on to heat.
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