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CHAPTER 19
Global
Change
Is this evidence of global warming?
Climate Change Debate?
• “The major scientific agencies of the United
States — including the National Aeronautics
and Space Administration (NASA) and the
National Oceanic and Atmospheric
Administration (NOAA) — agree that climate
change is occurring and that humans are
contributing to it.” - EPA
Questions Still Up For Debate
• Scientists are still researching a number of
important questions:
– Exactly how much will Earth warm?
– How quickly will it warm?
– What will the consequences of the warming be in
specific regions of the world?
Global Change
• Global change: any chemical, biological, or
physical property change of the planet (ex:
cold temperatures causing ice ages)
• Global climate change: changes in the climate
of the Earth
• Global warming: one aspect of climate
change, the warming of the oceans,
landmasses, and atmosphere of the Earth
Greenhouse Effect
• When radiation from the sun hits the
atmosphere, 1/3 is reflected back
• Some UV radiation is absorbed by the ozone layer
• Some strikes the Earth and is converted into lowenergy infrared radiation
• Infrared radiation then goes back toward the
atmosphere, where it’s absorbed by greenhouse
gases that radiate most of it back to the Earth
Greenhouse Gases
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•
•
•
•
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Water vapor (H2O)
Carbon dioxide (CO2)
Methane (CH4)
Nitrous oxide (N2O)
Chlorofluorocarbons (CFCs)
Ozone (O3)
Global Warming Potential
• Certain GHGs are more effective at warming
the Earth than others
• 2 most important factors:
– How well the gas absorbs energy
– How long the gas stays in the atmosphere
• Global Warming Potential (GWP) is a measure
of the total energy that a gas absorbs over a
particular period of time (usually 100 years),
compared to CO2
U.S. Greenhouse Gas Emissions in 2010
Natural Sources of Greenhouse Gases
• Carbon dioxide from volcanic
eruptions
• Methane from decomposition
• Nitrous oxide from
denitrification
• Water vapor
Anthropogenic Sources of Greenhouse
Gases
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•
•
•
•
Burning of fossil fuels
Agricultural practices
Deforestation
Landfills
Industrial production (ex: CFCs)
U.S. Carbon Dioxide Emissions, By Source
Particulate Matter
• Aerosols are a subset of air pollution that
refers to the tiny particles suspended in our
atmosphere
• Particles can be both solid and liquid
• Light-colored aerosol particles can reflect
incoming solar energy
• Dark particles can absorb solar energy
Greenhouse Effect
• http://www.youtube.com/watch?v=ZzCA60W
noMk&list=PLi_1unC2AWvBgO2QcF9pfnWlyg
4MemHAw
Radiative Forcing
• Energy is constantly flowing into the
atmosphere and being absorbed by Earth
• Some energy is always radiating back out into
space (infrared light)
• If:
– Energy flowing out > energy flowing in = cooling
– Energy flowing out < energy flowing in = warming
– Energy flowing out = energy flowing in = no
change
Radiative Forcing
• Energy is constantly flowing into the
atmosphere and being absorbed by Earth
• Some energy is always radiating back out into
space (infrared light)
• If:
– Energy flowing out > energy flowing in = cooling
– Energy flowing out < energy flowing in = warming
– Energy flowing out = energy flowing in = no
change
Radiative Forcing
• Energy is constantly flowing into the
atmosphere and being absorbed by Earth
• Some energy is always radiating back out into
space (infrared light)
• If:
– Energy flowing out > energy flowing in = cooling
– Energy flowing out < energy flowing in = warming
– Energy flowing out = energy flowing in = no
change
Radiative Forcing
• Radiative forcing is a direct measure of the
impact that human activities are having on
changing the planet’s climate
• Measured in watts per square meter (W/m2)
of surface
IPCC
• The Intergovernmental Panel on Climate Change
(IPCC) is the leading international body for the
assessment of climate change
• Established in 1988 by two United Nations
organizations: the World Meteorological
Organization (WMO) and the United Nations
Environment Programme (UNEP)
• Its mission is to provide the world with a clear
scientific view on the current state of knowledge in
climate change and its potential environmental and
socio-economic impacts
• Thousands of scientists and other experts contribute
(on a voluntary basis) to writing and reviewing
reports, which are reviewed by representatives from
all the governments
Increasing CO2 Concentrations
• David Keeling began measuring CO2 in 1958
Comparing Emissions
• Which country emits the most CO2?
• Which country emits the most CO2 per capita?
Comparing Emissions
CO2 Emissions Per Capita
• http://www.google.com/publicdata/explore?d
s=d5bncppjof8f9_&met_y=en_atm_co2e_pc&
idim=country:CHN&dl=en&hl=en&q=china%2
0co2%20emissions
What do you think?
• Should developing countries be held to the same CO2
emissions standards as developed countries?
• Things to consider:
– How did developed countries become so wealthy?
– Which countries are to blame for climate change?
– Will strict CO2 standards inhibit growth in developing
countries?
– Will developing countries be able to afford costly new
technology?
Global Temperature Change
• Since 1880, temperatures have increased 0.8°C
Global Temperature Change
• http://www.youtube.com/watch?v=SF5Fxped
Vlw&list=PLi_1unC2AWvBgO2QcF9pfnWlyg4
MemHAw
Temperatures & Greenhouse Gas
Concentrations in Past 400,000 Years
• No one was around thousands of years ago to
measure temperatures, so we must use
indirect measurements
– Changes in species composition
– Chemical analysis of ice
Ice Cores
• Ice cores contain an abundance of climate
information – more so than any other natural
recorder of climate like tree rings or sediment layers
• Although their record is short (in geologic terms), it
can be highly detailed and extend back hundreds of
thousands of years
• This record can include:
–
–
–
–
–
Temperature
Precipitation
Chemistry and gas composition of the lower atmosphere
Volcanic eruptions
Solar variability
Ice Cores
• http://www.youtube.com/watch?v=NENZ6TSc
1fo&feature=player_embedded
CO2 Concentration Throughout History
CO2 Heat Trapping
• http://www.youtube.com/watch?v=RTLU4VTZ9o&list=PLi_1unC2AWvBgO2QcF9pf
nWlyg4MemHAw
Sediment Cores
• Rarely disturbed ocean sediment cores can provide records up
to 180 million years ago as new layers of sediment bury and
preserve those of the past
• Fossilized specimens of microscopic foraminifera can provide
clues to the climate conditions during their lives
• Some species are only found in certain environments, so we
can reconstruct the sea level, ocean, and climate conditions of
that period based on our knowledge of foraminifera species
Oxygen Isotopes
• Ocean water during warmer times has a lower
18O / 16O ratio than ocean water during colder
times
• Foraminifera incorporate that oxygen into
their shells (CaCO3), which accumulate on the
ocean floor after they die
• We can estimate the water temperature by
the ratio of 18O / 16O in fossilized shells
Climate Models
• Scientists use climate data gathered from the
past to help predict the future
• Current models predict that average global
temperatures will increase 1.8⁰ – 4.0⁰ C (3.2⁰ –
7.2⁰ F) by 2100
Battery Drive
• Bring in your old batteries to HR and put in the
canisters this week
Feedback Loops
• What is a positive feedback loop?
• What is a negative feedback loop?
Positive Feedback Loop
Positive Feedback Loop
• We know that an increase in CO2 in the
atmosphere causes a greater capacity for
warming through the greenhouse effect
• Higher temperatures  warmer oceans 
oceans release CO2 gas into atmosphere
Negative Feedback Loop
AP Practice Question
• Which statement about feedback loops that occur
with climate change is true?
a) All feedback loops are positive.
b) All feedback loops are negative.
c) Increased soil decomposition under warmer
temperatures represents a positive feedback loop.
d) Increased evaporation under warmer temperatures
represents a negative feedback loop.
e) Increased plant growth under higher CO2 concentrations
represents a positive feedback loop.
Consequences of Global Warming
• Melting of polar ice caps, Greenland, and
Antarctica
• Melting of glaciers around the world
• Melting of permafrost
• Rising sea levels
• Heat waves and droughts
• Fewer cold spells
• Greater frequency and intensity of storms
Melting Ice Caps
Melting Arctic Ice Cap
• http://www.youtube.com/watch?v=8bHufxbxc8
Rising Sea Levels
Rising Sea Levels
• http://www.youtube.com/watch?v=aKoch_iEo
s8
Consequences to Living Organisms
• Changing growing season for
plants can harm animals if
they can’t move to better
climates
• Humans may have to relocate
• Diseases, like those carried by
mosquitoes, could increase
• Economic consequences
Controversy of Climate Change
• The fundamental basis of climate change (that
greenhouse gas concentrations are increasing
and that this will lead to global warming) is
not in dispute among the vast majority of
scientists
• What is unclear is how much world
temperatures will increase for a given change
in greenhouse gases, because that depends on
the different feedback loops
Kyoto Protocol
• In 1997, representatives of the nations of the world
went to Kyoto, Japan to discuss how best to control
the emissions contributing to global warming
• The agreement was that emissions of greenhouse
gases from all industrialized countries will be reduced
to 5.2% below their 1990 levels by 2012
• Developing nations did not have emission limits
imposed by the protocol
• http://www.cbc.ca/news/politics/story/2012/12/20/
pol-kyoto-protocol-part-one-ends.html
Climate Change Awareness
• The Nobel Peace Prize 2007 was
awarded jointly to Intergovernmental
Panel on Climate Change (IPCC) and
Albert Arnold (Al) Gore Jr. "for their
efforts to build up and disseminate
greater knowledge about man-made
climate change, and to lay the
foundations for the measures that are
needed to counteract such change"
Carbon Sequestration
• An approach involving taking CO2 out of the
atmosphere
• Some methods include storing carbon in agricultural
soils or retiring agricultural land and allowing it to
become pasture or forest
• Researchers are looking at cost-effective ways of
capturing CO2 from the air, from coal-burning power
stations, and from other emission sources
• This captured CO2 would be compressed and
pumped into abandoned oil wells or the deep ocean
• http://www.youtube.com/watch?v=ROEFaHKVmSs
Carbon Sequestration
AP Practice Question
• Which statement regarding the Kyoto Protocol is
true?
a) Developed and developing nations all agreed to reduce
their emission of greenhouse gases
b) All nations agreed to stop their emission of greenhouse
gases
c) The developed nations agreed to different levels of
emission reductions
d) Developing nations agreed to reduce their emission of
greenhouse gases
e) Developing nations agreed to stop their emission of
greenhouse gases
What Do You Think?
• What is the best way to reduce CO2
emissions?
– Force people and companies to be more energy
efficient and/or to use “green” technologies
OR
– Allow people and companies to pollute as much
as they want, but tax them on how much CO2 they
emit