2. Solar radiation passes through
the atmosphere and warms
Earth’s surface.
Energy is absorbed by Earth
surface & some re-radiated to
space.
Greenhouse gases trap some
heat near Earth’s surface.
o Water vapor*
o Carbon dioxide*
o Methane
o CFCs
o Nitrous oxide
Water vapor & CO2 store most
heat.
Earth would be too cold to live
on if we did not have the
greenhouse effect.
3. Carbon dioxide (CO2)
o Burning fossil fuels &
deforestation
Chlorofluorocarbons (CFCs)
o Refrigerants, Styrofoam,
propellants
Methane (CH4)
o Animal waste, biomass burning,
fossil fuels, landfills, livestock,
rice paddies, sewage, wetlands
Nitrous oxide- N20
o Biomass burning, deforestation,
microbes in soil
Water Vapor (H20)
o Evaporation, plant respiration
(transpiration)
4. Mauna Loa Observatory in
Hawaii used to measure
CO2 levels to infer a global
concentration.
Discovered two things:
o CO2 levels vary by season
• Winter- levels higher due to
decay releasing CO2 from
dead leaves.
• Summer – levels are lower
b/c plants are alive &
removing CO2 for
photosynthesis
o CO2 levels have increased
Keeling curve created by Charles
Keeling who discovered the change in
CO2 levels during seasons.
5. As greenhouse gas
concentrations increase,
the temperature on the
planet increases.
Predictions about future
growth of gases &
temperature are done
with computer modeling
o Enter data such as CO2
levels, wind, temperature
of oceans, etc into
computer equations that
predict future based on
changes in any of these
variables.
6. 1. Changes in global
weather patterns
2. Human health
problems
3. Agricultural impacts
4. Changes in plant &
animal behavior
5. Rising sea levels
7. 1. Changes in global
weather patterns
o As ocean heats up,
hurricanes & typhoons
will become more
common
o Cause changes in
ocean currents, which
cause changes in
weather.
• Ex: Places that are wet
become dry
8. 2. Human Health
Problems
o Hotter in cities
o Longer pollen season-
affecting people with
seasonal allergies
o Disease carrying insects
may expand their ranges
if it stays warmer longer
in places that were
previously too cold for
them.
9. 3. Agricultural Impacts
o Crop yield may
decrease if climate
changes
o As droughts increase,
the demand for
irrigation water
increases putting more
stress on already
depleted aquifers.
10. 4. Changes in plant & animal
behavior
o As cold habitats warm,
different plants may invade
& grow, altering the diversity
of the habitat.
o Bird migrations may change
o Some animals will wake up
from hibernation earlier and
go back into hibernation
later… how would this affect
their food supply?
o Coral reefs rely on algae- if
algae die due to increased
ocean temperature coral
reefs die- called coral
bleaching.
11. 5. Rising sea levels
o Ice sheets, glaciers, &
snow in Greenland &
Antarctica are melting
o Coastal communities
most affected
• Saltwater will contaminate
coastal aquifers
• Homes may be washed
away
• Estuaries & wetlands are
nurseries for many animals.
Offspring may not be as
tolerant to increased salt
12.
13.
14.
15. Positive Feedback Loop
As CO2 increases, the
atmosphere warms. This warms
the oceans and the oceans take
up less CO2. This means more
CO2 stays in the air and the
cycle starts all over again.
Ex: Albedo Effect
Albedo- reflectivity of a surface
Ice reflects heat.
Water absorbs heat.
As we lose ice, less heat gets
reflected and more heat gets
absorbed and ice melts even
more. See the next series of
slides and notice the size of the
ice pack and the arrows that
show reflection & absorption.
20. IPCC- Intergovernmental
Panel on Climate Change
2500 of the world’s leading
climatologists from 70
countries
Released report on
changes in global climate:
o Global surface temp have
increased by 0.6C during 20th
century
o Snow & ice extent have
decreased
o Average global sea level has
risen
o Greenhouse gas increase is
due to human activity
21. 1997- 160 countries came
together to discuss reducing
greenhouse gas emissions.
Created Kyoto Protocol
o Requires developed countries to
decrease emissions of CO2 and
other greenhouse gases by 5%
below their 1990 levels by 2012.
o When 55% of the attending
nations ratify this treaty it will go
into effect.
o Currently US and China (the
biggest greenhouse gas emitters)
have not signed.
• US did not sign b/c there were no
mandates in place for developing
countries (like China)
• US felt like China was an emerging
powerhouse and should be subject to
the same standards as developed
countries.
Kyoto Protocol News - The New
York Times
22. Explain why Earth’s atmosphere is like the glass in a
greenhouse.
Explain why carbon dioxide in the atmosphere is
increasing.
Explain one theory for why Earth’s climate is becoming
warmer.
Name some of the possible consequences of a warmer
Earth.