Unit 6 : Atmosphere and Climate
A. Earth’s Atmosphere
1. atmosphere is composed of the following :
a. Nitrogen (71%)
b. Carbon (28%)
c. trace gases (1%) – argon,
methane, hydrogen, and helium
2. atmosphere also contains ozone (O3)
which absorbs UV radiation
B. 5 Layers of the Atmosphere
1. Troposphere
a. layer closest to Earth’s surface
b. where most weather takes place and most air pollution collects
c. temperature decreases with altitude
2. Stratosphere
a. layer made primarily of ozone
b. where jet stream is located
c. temperature increases with altitude due to absorption of UV radiation
3. Mesosphere
a. where most meteoroids are burnt up as they enter our atmosphere
b. temperature decreases with altitude
4. Thermosphere
a. layer where radio waves are transmitted
b. where space shuttles are found
c. ionosphere is located here – a layer of
charged ions that cause Aurora Borealis and
Aurora Australis at poles
d. temperature increases with altitude due to
solar radiation
5. Exosphere
a. outermost layer where satellites can be found
b. temperature in this layer decreases with lower air pressure
C. Climate and Weather
1. weather is the condition of the atmosphere over a short period of time
2. climate is the average daily weather for an extended period of time at a certain
location
3. temperature and precipitation determine climate
4. factors that affect climate
a. latitude
b. elevation
c. topography
d. water bodies
e. atmospheric circulation
f. vegetation
D. Climate
1. The Köppen Climate Classification System – organizes the world’s climates into
categories based on the annual and monthly averages of temperature and
precipitation
2. 3 major climate zones based:
a. polar – coldest with temperatures below freezing
b. temperate – more moderate temperatures and rainfall year-round
c. tropical – warmest average temperatures with the most precipitation
E. Natural Processes that Change Climate
1. El Niño
a. associated with a band of warm ocean water temperatures that
periodically develops off the Pacific coast of South America
b. happens every 2 to 7 years and can last from 9 months to 2 years
c. in South America, this leads to
i. increased temperatures and rainfall
d. in North America, this leads to
i. mostly drier and warmer conditions
e. effects both fishing and farming industries
2. La Niña
a. climate pattern represented by the cooling of the eastern tropical Pacific
Oceans
b. in South America, this leads to
i. in some areas, drought
ii. in other areas, excessive rainfall, leading to flooding
c. in North America, this leads to
i. above average rainfall in the northern regions
ii. below average rainfall in the southern regions
iii. allows for more stronger-than-average hurricanes off the Atlantic
andlessin the Pacific
d. effects both fishing and farming industries
3. Volcanic eruptions
a. increases the amount of solar radiation that is reflected back into space,
decreasing the temperature of the atmosphere
4. Sunspots
a. sunspot – dark blemishes that appear
with the sun is most intense (active)
b. associated with increased temperatures
in Europe and North America
c. when sun is less intense (active),
there is a decrease temperatures
5. Earth’s orbit
a. Earth’s orbit around the sun is elliptical, which can bring the Earth closer
to the sun, warming the Earth
6. Earth’s tilt
a. the angle of the tilt varies which changes the severity of the seasons
7. Carbon dioxide
a. atmosphere CO2 has increased by almost 40% since pre-industrial times
b. this increase in CO2 has increased global temperatures by absorbing heat
from the sun
F. Greenhouse Effect
1. greenhouse effect – natural warming of Earth and it’s atmosphere
2. when sunlight reaches Earth’s surface, it can either be reflected back into space
or absorbed by Earth
3. greenhouse gases – gas that absorbs and releases radiation
4. examples of greenhouse gases include
a. water vapor (H2O)
b. carbon dioxide (CO2)
c. methane (CH4)
d. nitrous oxide (NO)
5. greenhouse gases lead to the greenhouse effect by acting like a blanket,
trapping sun’s heat close to the Earth’s surface
6. CO2 is the primary greenhouse gas that contributes to climate change
a. it is released by animals and plants through respiration
b. also released by burning of fossil fuels by humans
c. deforestation (clearing land) for agriculture, industry, and urbanization
have also increased CO2 concentrations
7. warmer conditions can lead to more evaporation and precipitation
8. a stronger greenhouse effect will warm the oceans and partially melt glaciers
and other ice, increasing the sea level
G. Global Temperatures
1. increased temperatures will cause drought conditions effecting agriculture
2. species that are able to adapt more quickly to increased temperatures and rapid
temperature changes will become more abundant
3. loss of biodiversity in ecosystems will be widespread and species diversity will
decline
4. increased global temperatures raise sea levels worldwide
H. Heat Islands
1. heat islands – a metropolitan areas that is significantly warmer than
surrounding areas due to human activity
2. open air and vegetation is replaced by urbanization
3. increases energy demands, air conditioning costs, air pollution,
greenhouse gas emission, heat-related illness and mortality, and water
quality
4. to reduce heat island effect :
a. plant trees and vegetation
b. using eco-friendly building materials
I. Land Use
1. urbanization- increasing the number of people that live in urban areas
a. closely linked with modernization and industrialization
b. results in heat islands
2. deforestation – removal of trees in a forest for the conversion of farms,
ranches, or urban use
a. trees are sold or land is used for human purposes
b. deforestation without sufficient reforestation has resulted in the loss of
habitats and biodiversity
3. agriculture – cultivation of animals and plants for food, fuel, or medicines to
sustain human life
a. leads to loss of natural habitats