Transcript Climate Change

Global Climate Change:
Impact and Remediation
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CQ#1: Based on your current knowledge, which
statement is closest to your thoughts about the
consequences for humans of global climate
change?
A. The effects of climate change, if any, will be small
compared to natural changes that have occurred
before.
B. The effects of climate change will be minor except in
poor, less developed countries.
C. Climate change will significantly affect many countries.
D. The effects of climate change will be catastrophic
around the world.
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Why is there so much concern about
climate change?
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Predicted consequences of global climate change include:
1. Melting of continental and polar glaciers and sea ice.
2. A rise in sea level and loss of coastal communities.
3. Damage to ecosystems and reduced survival of
threatened species.
4. Reductions in our food supply due to changes in
agricultural conditions.
5. Increased threats to human health from new diseases
and changing disease distributions.
1. Glaciers are melting
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According to the National Snow & Ice Data Center:
“Because glaciers are sensitive to temperature
fluctuations, they provide clues about the effects of
global warming. With few exceptions, glaciers around
the world have retreated at unprecedented rates over
the last century. Some ice caps, glaciers, and even an
ice shelf have disappeared altogether. Many more are
retreating so rapidly that they may vanish within
decades.”
http://www.climatecentral.org/videos/climate-incontext/watch-63-years-of-global-warming-in-14seconds
Glacial retreat can be judged from photographs taken
from the same location decades apart.
5 (top) and 2005 (bottom).
Muir Glacier, Alaska, in 1890
Muir Glacier, Alaska, in 1880 (left) and 2005 (right).
Muir Glacier, Alaska, in 1941 (left) and 2004 (right).
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1. Glaciers are melting
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•Melting glaciers, which supply drinking and
irrigation water for hundreds of millions of
people around the world, will be lost.
•In addition, melting glaciers lead to rising sea
levels and regional precipitation decreases.
•Greenland:
http://www.youtube.com/watch?v=umVW9T7j3U
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2. Sea level is rising
• Because most glaciers are melting, sea
level is rising.
• In addition, the oceans’ surfaces are
warming because of climate change, and
this expands the water and adds to sea
level rise.
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2. Sea level is rising
• From 1993-2003, the estimated rate of sea
level rise from both causes has been about
2.4 centimeters/decade.
• Oceans are predicted to rise about 12
centimeters in the next 50 years.
• Coastal erosion rates are about 100 times
the rate of sea level rise, which means that
every centimeter of sea level rise results in
1 meter of beach erosion.
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Coastal
Flooding
and
Erosion
Miami Beach,
Florida.
Current sea
level (top);
Estimate at
2030-- +1 m
(bottom)
http://www.yout
ube.com/watch
?v=_4YUieDlA
uM
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Are larger changes possible?
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Ice caps in Greenland and Antarctica together hold 70% of
the world's fresh water— enough to potentially raise the
sea level approximately 225 feet. But changes this large
are thought to be extremely unlikely in the next century.
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The implications of melting sea ice
•Sea ice tends to reflect sun’s energy; sea water tends to
absorb sun’s energy.
•When more sea ice melts in summer, there is more open
water to absorb energy and heat up.
•The following winter it takes longer for sea ice to form due to
warmer water and thinner ice.
•Then, more melting takes place the next summer, which
warms the water even more… and so on…
The “…and so on” is an indicator of a positive feedback
process. Now that melting has started, it might accelerate
because of the positive feedback.
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Another positive feedback loop:
Melting permafrost 15
 Warming climate is melting the
permafrost in Canada, Alaska, and
Scandinavia.
 This increases wetlands.
 The wetlands release methane and
carbon dioxide.
 which are greenhouse gases …
more positive feedback effects!
3. Animals and ecosystems depend on climate
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Polar bears and their prey
need sea ice
Reef organisms depend on
specific temperatures
Climate change adds to stress that may already exist from human
use and pollution: Will these animals be able to adapt?
4. Agricultural systems depend on climate
Climate change
will affect
production of food,
fiber, and wood
products.
Will the benefits of
change exceed
the losses?
Will agriculture be
able to adapt to
change?
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Projected Changes in Agriculture in 2080 due to Climate Change
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Wealthier nations may be better able to adapt.
Will they be able to feed the world?
Morbidity (illness), mortality (death), and displacement (migration of
population) could increase. For example, if malaria-carrying
mosquitoes could move north, illness and death from malaria could
move north as well, and people might respond by moving to even
higher latitudes.
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Health effects will not be the same everywhere
Which parts of the world have not been affected much by
climate change so far? How and why might this change?
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How do we cause climate change?
The most significant cause of climate change is emission of
greenhouse gases (GHG), such as CO2, into the atmosphere
from human activities.
In the U.S., most
emissions result
from using
energy. Net
emissions are
large even though
some land uses
actually remove
GHG from the air.
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Responding to climate change
Mitigation
• Reduce greenhouse gas (GHG)
emissions. Drastic reductions could
stabilize GHG in the atmosphere, but
GHG remain in the atmosphere a
long time so levels would not drop
right away.
• Sequestration. Land use and
forestry practices that store CO2 in
soil and plants can lower GHG levels
in the atmosphere.
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Responding to climate change
Mitigation
Geologic sequestration: Remove
greenhouse gas emissions from
the air and store it in the earth or
oceans. But the technology to
do this does not exist and might
take decades to develop.
Adaptation
Climate change is occurring now
and further change is inevitable.
Adaptation means altering our
economy and our lives to cope
with those changes.
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Rigs that pump oil out of
Earth today might be able to
put CO2 back in the future.
CQ#9: In the graph below, direct emissions result from using fossilbased fuels such as gasoline and fuel oil while electricity-related
emissions result from using fossil fuels, such as coal, to generate
electricity. Thus, the generation of electricity represents the greatest
proportion of GHGs in the ____ sector(s). (Choose the best answer)
A.
B.
C.
D.
Residential
Commercial
Industrial
Residential and
commercial
E. All of the above
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Practices and technologies
We can reduce emissions by:
Conservation: Use less energy (e.g., turn off lights, machines
and engines when they’re not in use).
Conversion: Change to low-emission energy sources (e.g.,
renewable fuels emit fewer GHG than fossil fuels).
Efficiency: Use technologies that get the most from an energy
source (e.g., Energy Star appliances).
Waste reduction: Eliminate materials that require energy to
landfill (e.g., compost organics instead of creating trash).
Sequestration: take GHG out of the air (e.g., maintain and
increase crops and land uses that hold carbon in soils).
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What can you do?
The most important step is to find out how much GHG your
lifestyle creates. Use one or more of the following online
calculators to find out. Then use the GHG-reducing tips on
these sites to reduce your GHG production.
The US EPA household emission calculator
(http://www.epa.gov/climatechange/emissions/ind_calculator.html)
The Nature Conservancy carbon footprint calculator
(http://www.nature.org/initiatives/climatechange/calculator/
Carbonfootprint.com
(http://www.carbonfootprint.com/)
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