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Chapter 19
Global Change
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Explain how solar radiation and greenhouse gases
warm our planet.
Discuss how CO2 concentrations and temperatures
have changed over time.
Describe the importance of feedback loops in the
process of global warming.
Identify how global warming is affecting people and
the environment.
Discuss how the Kyoto Protocol aims to reduce global
warming.
The Greenhouse Effect
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When radiation from the sun hits the atmosphere, 1/3
is reflected back.
Some of the UV radiation is absorbed by the ozone
layer and strikes the Earth where it is converted into
low-energy infrared radiation.
The infrared radiation then goes back toward the
atmosphere where it is absorbed by greenhouse gasses
that radiate most of it back to the Earth.
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Venus: 864˚ F
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Mars: -80˚ F (-193 F to 70 F)
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Atmosphere: carbon dioxide (100x thinner than
Earth)
Moon: Ranges from -253˚ F to 243˚ F
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Atmosphere: carbon dioxide with some nitrogen
(90x denser than Earth)
No atmosphere
Earth: 61˚ F (ranges from -129˚ F to 134˚ F)
Greenhouse Gases
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The major greenhouse gases are water vapor,
carbon dioxide, methane, nitrous oxide, and
anthropogenic ozone
Greenhouse warming potential- estimates
how much a molecule of any compound can
contribute to warming over a period of 100
years relative to a molecule of CO2
Actual contribution is a factor of warming
potential and concentration in the atmosphere
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How does the energy of the Sun cause Earth to
heat?
What is a greenhouse gas? Which greenhouse
gases are the most common on Earth?
What determines the effect of a greenhouse
gas? Which greenhouse gas has the strongest
effect?
Natural Greenhouse Gases
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Volcanic eruptions- mainly carbon dioxide.
Ash and other gases can have a short-term
effect on the climate by reflecting sunlight and
cooling the atmosphere
Methane– from anaerobic decomposition
Nitrous oxide- from denitrification occurring in
wet soils and at the bottom of bodies of water
Water vapor- from evaporation and
evapotranspiration
Anthropogenic Causes of
Greenhouse Gases
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Burning of fossil fuels
Agricultural practices, such as flooding fields,
raising livestock, and applying fertilizers
Deforestation
Landfills
Industrial production- CFC’s are an example
These charts show
the largest
contributors of
different
greenhouse gases
Increasing CO2 Concentrations
Carbon dioxide levels have risen steadily since measurement began in 1958
Emissions from the Developed
and Developing World
Global Temperatures since 1880
http://www.climate4you.com/
http://data.giss.nasa.gov/gistemp/graphs/Fig.
A2.lrg.gif
Between 2000-2009, some regions have become cooler, some have had no
temperature change, and the northern latitudes have become warmer.
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The term "heat island" describes built up areas that are
hotter than nearby rural areas. The annual mean air
temperature of a city with 1 million people or more can
be 1.8–5.4°F (1–3°C) warmer than its surroundings. In
the evening, the difference can be as high as 22°F
(12°C). Heat islands can affect communities by
increasing summertime peak energy demand, air
conditioning costs, air pollution and greenhouse gas
emissions, heat-related illness and mortality, and water
quality. (US EPA)
Lawrence Berkeley National Laboratory
Atlanta, GA (Wikipedia Commons)
The numbers shown in the lower right corner represent the temperature anomaly relative to the above average. Values
are rounded off to the nearest two decimals, even though some of the original data series come with more than two
decimals.Last month shown: December 2015. Last diagram update: 25 January 2016. www.climate4you.com
The record spans over four glacial periods and five interglacials, including the
present. The horizontal line indicates the modern temperature. The red square to
the right indicates the time interval shown in greater detail in the following figure.
www.climate4you.com
The upper panel shows the air temperature at the summit of the Greenland Ice Sheet, reconstructed by
Alley (2000) from GISP2 ice core data. The lower panel shows the past atmospheric CO2 content, as
found from the EPICA Dome C Ice Core in the Antarctic (Monnin et al. 2004). The Dome C atmospheric
CO2 record ends in the year 1777. www.climate4you.com
Temperatures and Greenhouse Gas
Concentrations in Past 400,000 Years
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No one was around thousands of years ago to measure
temperatures so we use other indirect measurements,
called proxies. Some of these are
 Changes in species compositions
 Chemical analyses of ice
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Ice cores, extracted from glaciers, have tiny
trapped air bubbles of ancient air that can
provide estimates of greenhouse gas
concentrations and temperatures
Comparing oxygen isotopes (O16 to O18) allows
an estimate of global temperatures
Tiny shells of protists, called foraminifera, become buried in layess of ocean sediments. By
knowing the age of the sediment and the preferred temperature of different species of
forams, scientists can indirectly estimate ocean temp changes over time.
Putting It Together
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We know that an increase in CO2 in the
atmosphere causes a greater capacity for
warming through the greenhouse effect.
When the Earth experiences higher
temperatures, the oceans warm and cannot
contain as much CO2 gas and, as a result, they
release CO2 into the atmosphere.
www.climate4you.com
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What are the differences in CO2 emissions in
developed and developing nations?
How do scientists know the concentration of
atmospheric CO2 or the average global
temperature from the distant past? What are
the ways they can tell?
Why are climate models important? What are
some challenges associated with them?
Feedbacks
Consequences to the Environment
Because of Global Warming
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Melting of polar ice caps, Greenland and Antarctica
Melting of many glaciers around the world
Melting of permafrost
Rising of sea levels due to the melting of glaciers and
ice sheets and as water warms it expands
Heat waves
Cold spells
Change in precipitation patterns
Increase in storm intensity
Shift in ocean currents
Sea levels are rising at an average rate of 3 mm/yr.
Global sea level since December 1992 according to the Colorado Center for Astrodynamics Research at
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Global warming could alter ocean currents and
cause both excessive warming and severe cooling.
Figure 20-12
Consequences to Living
Organisms
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Wild plants and animals can be affected. The
growing season for plants has changed and
animals have the potential to be harmed if they
can’t move to better climates.
Humans may have to relocate, some diseases
like those carried by mosquitoes could increase
and there could be economic consequences.
In the Netherlands, the bird’s
main food source, a
caterpillar, now becomes
abundant two weeks earlier
because of a warming climate.
The time when eggs hatch for
the flycatcher has not
changed, so the birds hatch
after the caterpillar population
has peaked.
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This ongoing acidification of the oceans poses a
threat to the food chains connected with the
oceans.
Thomas Lovejoy, former chief biodiversity
advisor to the World Bank, has suggested that
"the acidity of the oceans will more than
double in the next 40 years. This rate is 100
times faster than any changes in ocean acidity
in the last 20 million years, making it unlikely
that marine life can somehow adapt to the
changes.“
http://en.wikipedia.org/wiki/Ocean_acidification
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Refers to the ongoing decrease in the pH of the Earth's
oceans, caused by the uptake of anthropogenic carbon
dioxide from the atmosphere. About a quarter of the
carbon dioxide in the atmosphere goes into the oceans,
where it forms carbonic acid.
As the amount of carbon has risen in the atmosphere
there has been a corresponding rise of carbon going
into the ocean. Between 1751 and 1994 surface ocean
pH is estimated to have decreased from approximately
8.25 to 8.14, representing an increase of almost 30% in
"acidity" (H+ ion concentration) in the world's oceans.
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What is the evidence that global warming is
affecting Earth?
What changes are predicted to occur as
temperature increases?
How will climate change affect humans? What
are some examples of direct and indirect
effects?
The Kyoto Protocol
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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.
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The process of capture and long-term storage
of atmospheric carbon dioxide to slow down or
prevent global warming
Is a type of mitigation
Methods of capturing carbon include:
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Making artificial peat bogs
Reforestation
Wetland restoration
Using green manure or no-till agriculture
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Methods of reducing carbon in the atmosphere
include:
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Reducing carbon emissions
Iron fertilization of the oceans (increases growth of
algae and phytoplankton)
Biochar (creating charcoal with waste biomass and
burying it in the ground)
Injecting CO2 into expired oil or gas wells or
injecting it into the deep ocean
Chemically combining it with metals to form
carbonates, which can be put in the ocean
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Post combustion capture: CO2 is removed after
combustion of the fossil fuel from flue gases at power
stations or other large point sources.
Pre-combustion capture: the fossil fuel is partially
oxidized. The resulting syngas (CO and H2O) is shifted
into CO2 and more H2. The resulting CO2 can be
captured from a relatively pure exhaust stream. The H2
can now be used as fuel.
Oxy-fuel combustion: the fuel is burned in oxygen
instead of air. The result is an almost pure carbon
dioxide stream that can be transported to the
sequestration site and stored
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We can improve energy efficiency, rely more
on carbon-free renewable energy resources,
and find ways to keep much of the CO2 we
produce out of the troposphere.
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Two ways to deal with global warming:
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Mitigation that reduces greenhouse gas emissions.
Adaptation, where we recognize that some warming is
unavoidable and devise strategies to reduce its harmful
effects.
The Controversy of Climate
Change
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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.
Solutions
Global Warming
Prevention
Cut fossil fuel use (especially
coal)
Shift from coal to
natural gas
Cleanup
Remove CO2 from smoke stack
and vehicle emissions
Store (sequester)
CO2 by planting trees
Improve energy efficiency
Shift to renewable energy
resources
Transfer energy efficiency and
renewable energy technologies
to developing countries
Reduce deforestation
Use more sustainable
agriculture and forestry
Limit urban sprawl
Reduce poverty
Sequester CO2 deep underground
Sequester CO2 in soil by using
no-till cultivation
and taking cropland out
of production
Sequester CO2 in the deep ocean
Repair leaky natural gas pipelines
and facilities
Use animal feeds that reduce CH4
emissions by belching cows
Slow population growth
Fig. 20-14, p. 481
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What is the Kyoto Protocol?
How is the Kyoto Protocol and example of the
precautionary principle?
How will the Kyoto Protocol affect developing
countries? How will it affect developed
countries?