Download ENVI 30 Environmental Issues

IPCC
AR4
Climate Change – Greenhouse Gases
A.
Background
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Greenhouse Effect
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B.
Gases absorb heat (long-wave radiation)
Natural Greenhouse Effect
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Mean planetary temperature = 15 oC vs. -6 oC
Enhanced Greenhouse Effect
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Due to GHGs emitted from human activity
Greenhouse Gases
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Most important GHG is water vapor
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Accounts for ~50% of natural GHE
Historically: Belief that human activities didn’t
affect atmospheric moisture content
Recent evidence that humans affect atmospheric
humidity (Santer et al. 2007, Willett et al. 2007)
Greenhouse Gases
Gas
Sources
Residence Radiative Influence
Time (y)
Forcing
(GHGs)
FF combustion
Deforestation
Biomass burning
50-200
1
63%
Rice paddies
Cattle/Termites
Landfills
FF Production
10
21
18%
Nitrous
Oxide
Fertilizers
Deforestation
Biomass burning
150-170
206
6%
Halocarbons
Industrial processes
Electrical transmission
Substitution for ozonedepleting substances
15-650
10,700 –
15,800
13%
Carbon
Dioxide
Methane
US EPA
Climate Change – Greenhouse Gases
B.
Greenhouse Gases
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Some features of CO2/Temperature
relationship don’t correlate well. Why not?
Other factors besides GHGs may influence
global climate
Climate Change – Other Factors
A.
Cloud Cover
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B.
Reflects incoming radiation
Difficult to estimate in climate models
Effects vary in relation to altitude, thickness,
composition
Atmospheric Dust
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Important factor in cool period from 1930s to 1960s
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Produced by volcanic eruptions, dust from areas
experiencing drought
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Overwhelmed effects of rising CO2 during this period
Cool period following eruption of Mt. Pinatubo in 1992
Mechanism behind “Nuclear Winter” scenario
Climate Change – Other Factors
C.
Volcanism
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Affects water vapor, particles, sulfides, nitrates
Generally leads to planetary cooling
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D.
Theory about extinctions at P/T boundary
Mt. St. Helens and Mt. Pinatubo eruptions caused
planetary cooling, and those were small eruptions
Photosynthesis & Transpiration
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Affect CO2, water vapor
As [CO2] rises, some plants
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Photosynthesize more rapidly
Grow faster
Incorporate more CO2 into biomass
Keep their stomata open less
Transpiration releases water vapor into atmosphere
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Less transpiration when [CO2] is higher (stomata)
Climate Change – Other Factors
E.
Solar Output
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May affect amount of incoming radiation
Solar output varies – sunspots, solar flares
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Sunspots: magnetic storms that appear as dark
patches on sun’s surface
Sunspot cycles of 11, 88, 205 years
During sunspot maxima, solar output ca. 0.1%
higher than normal
http://calspace.ucsd.edu/virtualmuseum/climatechange2/06_3.shtml
Climate Change – Other Factors
E.
Solar Output
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Researchers have correlated sunspot
minima with “Little Ice Age” in Europe
during 17th and early 18th centuries when
sun was 0.25% dimmer than normal
20th century dominated by sunspot maxima
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Some predictions that 21st century will see minima
Controversial
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IPCC (2007): Solar output variation is ~14x less
influential than GHGs
 Global patterns
Regional variation
Lean 2010
Climate Change – Other Factors
F.
Albedo (Reflectivity)
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Earth’s surface varies considerably (mean =
0.30-0.36)
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Ice/Snow highly reflective (0.9)
Clouds vary in reflectivity
Land generally less reflective
Changes in land use affect albedo
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Desertification increases albedo
Melting of snow/ice decrease albedo
Climate Change – Other Factors
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Many factors affect global climate in multiple
ways
Ex – Clouds absorb long-wavelength radiation
(heat) and reflect incoming short-wavelength
radiation (light)
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Ex – Particles in atmosphere reduce reradiation of long-wavelength radiation and
reflect incoming short-wavelength radiation
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Net effect = cooling
Net effect probably warming at low levels, cooling at
high levels (e.g. following a large volcanic eruption)
Efforts to reduce particulate air pollution facilitate
warming
Uncertainty about impact of many factors
IPCC AR4
IPCC
AR4
Climate Change – Effects
A.
Negative
1.
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Sea Level
Warming  melting of glaciers and ice caps
 sea level rise
Warming  thermal expansion of water 
additional sea level rise
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Melting of all ice  sea level rise of ~70 m
http://www.epa.gov/climatechange/science/futureslc_fig1.html
Climate Change – Effects
A.
Negative
1.
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Sea Level
Since 1880, sea level has been rising at a rate of ~15
cm century-1
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Accelerating since 1940s
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Some polar ice sheet loss
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Loss of temperate glaciers
Warming should  more atmospheric moisture and
precipitation, which should  net growth of polar ice
caps
Examples
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Bangladesh: Over 20 million people live less than 1 m
above sea level
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~40% of food production tied to flood plains
AOSIS (Alliance of Small Island States) – Strong
concerns about sea level rise
US East Coast –Sea Level Rise
1m
3m
http://vrstudio.buffalo.edu/~depape/warming/east.html
www.panoramio.com/photo/31807235
- Sea level rise is not globally uniform
http://sealevel.colorado.edu/files/current/sl.pdf
Climate Change – Effects
A.
Negative
2.
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Rainfall Patterns
Warming should lead to
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Reduced precipitation at low latitudes
Increased precipitation at high latitudes
Examples
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Reduced snowpack in Sierra Nevada Mountains
due in part to rainfall instead of snow
Drought in many parts of the world
1958-2008
US Global Change Research Progam
Climate Change – Effects
A.
Negative
3.
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Storms
Warming should lead to
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More severe storms
Greater storm frequency
http://www.ncdc.noaa.gov/extremes/cei/
Climate Change – Effects
A.
Negative
4.
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Ecosystem Changes
Shifting climatic zones could expand ranges of
warmth-tolerant species and contract ranges of
warmth-intolerant species
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Within an ecosystem, some species will be more
sensitive to climate change than others
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Colder-living species might be displaced poleward as
well as upward in elevation
Species unable to adapt or move would go extinct
Predicted rates of 16.9 km/decade and 11.0 m/decade
(Chen et al. 2011)
Species composition of ecosystems almost certainly
will change
Changes in CO2 concentrations  pH of ocean
Chen et al. 2011
Climate Change – Effects
A.
Negative
4.
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Ecosystem Changes
Shifting climatic zones could expand ranges of
warmth-tolerant species and contract ranges of
warmth-intolerant species
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Within an ecosystem, some species will be more
sensitive to climate change than others
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Colder-living species might be displaced poleward as
well as upward in elevation
Species unable to adapt or move would go extinct
Predicted rates of 16.9 km/decade and 11.0 m/decade
(Chen et al. 2011)
Species composition of ecosystems almost certainly
will change
Changes in CO2 concentrations  pH of ocean
Climate Change – Effects
A.
Negative
5.
Health
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Consistently elevated
temperatures can lead to
immunosuppression
Allergies could worsen
due to increased pollen
production, dust
(desertification), mold
(humidity)
Additional human
mortality from severe
summer heat
Climate Change – Effects
A.
Negative
6.
Tropical Pests and Diseases
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Many tropical diseases are transmitted by animal
vectors – insects, rodents
Vector distribution often is limited by climatic barriers
(e.g. mountain ranges)
Ex: Malaria
Most prevalent vector-borne disease (1-2 million
cases/year)
Transmitted by Anopheles mosquitoes
Warming could lead to
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Broader geographic range (estimate that +2oC could
expand range from 42 to 60% of global land area)
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Higher mosquito metabolic rate  More food
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Faster maturation  More rapid reproduction
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Faster parasite life cycle
Potential spread into large urban areas (Nairobi, Kenya;
Harare, Zimbabwe) with immunologically naïve pop’ns
Projections are controversial and highly variable
Climate Change – Effects
B.
Positive
1.
Plant Growth
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2.
Warmer temperatures and elevated [CO2]  faster
plant growth & greater food production per acre
Elevated [CO2] should  more efficient use of
water, reduced runoff and less water pollution
Enhanced plant growth should remove CO2 from
atmosphere faster (Gaia Hypothesis)
Agriculture
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Expansion of agricultural regions
Longer growing season in areas that currently are
marginal for agriculture
Climate Change – Effects
B.
Positive
3.
Rainfall Patterns
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4.
Predictions of increased rainfall in major
agricultural regions, especially in northern
hemisphere
Reduced irrigation required for plants/crops
Increased precipitation (as snow) should cause
glaciers and ice sheets to grow
Milder Winters
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Severe winters pose a health and safety risk
Fewer expenses associated with less severe
winter weather
III. Climate Change – Projections
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Complexity and uncertainty in climate
models
Unknown response of earth climate
system to a forcing function
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Accumulation of GHGs in atmosphere
What should we do?? And why?
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Lomborg
IPCC
AR4
Some Responses to Global Climate Change
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Deny it altogether
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Stress scientific uncertainty and do nothing beyond calling for more
scientific research
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Geoengineering
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Adaptation
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Mitigation
Vulnerability
Who is most likely to get hit the hardest—suffer the greatest costs—by
climate change?
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Global South
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Lower income and marginalized communities and the poorer sectors
of societies (poor pays, not polluter pays)
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Non-dominant groups of people in countries with strong ethnic,
religious, and other divides
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Women and children
One Attempt to Sort out the Ethical Dimensions of
Global Climate Change
As per the title “A Perfect Moral Storm: Climate Change, Intergenerational
Ethics and the Problem of Moral Corruption” (2006) Stephen M. Gardiner
claims that climate change poses nearly insurmountable ethical problems.
Climate change involves:
1. dispersion of causes and effects in terms of space and time,
2. fragmentation of human agency in terms of space and time,
3. and institutional inadequacy in terms of space and time,
4. all subject to human corruption.
First and Second Spatial Perspectives
of the Moral Storm
1.
Dispersion of causes and effects of climate change
makes it hard to pinpoint moral geographical locations.
2.
Fragmentation of human agency makes it difficult to
respond to climate change. From an individual’s
perspective, it’s rational not to restrict one’s own
pollution, while from a collective perspective it’s
rational to restrict pollution = tragedy of the commons.
Third Spatial Perspective of the Moral Storm
Institutional inadequacy hampers efforts to respond to
climate change because:
1.
There is no effective global governance system.
2.
Some nations might wonder if they will be better or worse off
because of climate change.
3.
Effectively mitigating climate change might require deep and
profound changes to economic, political, and social structures.
First Temporal Perspective of the Moral
Storm
Dispersion of causes and effects over time might undermotivate people to effectively respond to climate change
because:
1.
Climate change is a resilient and substantially deferred
phenomenon.
2.
Climate change impacts are seriously back-loaded.
Second Temporal Perspective
of the Moral Storm
Fragmentation of human agency across time makes it
difficult to respond to climate change. From an individual
generation’s perspective, it’s rational not to restrict
current pollution, while from a collective intergenerational
perspective it’s rational to restrict pollution.
This is an intergenerational tragedy of the commons.
Third Temporal Perspective
of the Moral Storm
This intergenerational tragedy of the commons has multiplier effects,
namely:
1.
Inaction now raises transition costs that might make future change
more difficult.
2.
Insufficient action now might make some generations suffer
unnecessarily (e.g., climate change harms future generations A, B,
and C, but current inaction leads to harming future generations D
and E as well).
3.
Insufficient action now might result in tragic choices for future
generations.
Moral Corruption
Humans are often:
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Distracted
Complacent
Unreasonable
Self-deceptive
Manipulative
Selectively attentive
Delusional
Hypocritical
Because of these human characteristics, and because climate change
involves a complex convergence of problems, we will often fall prey
to moral corruption. How will we ever successfully deal with climate
change?
Climate Change and Some Dimensions
of Environmental Equity and Justice
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Distributive Justice: What is a fair or equitable distribution of the burdens and
benefits of climate change?
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Intragenerational equity: What steps should be taken to ensure that marginalized
and vulnerable people within current generations do not disproportionately suffer from
climate change impacts?
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Intergenerational equity: What steps should be taken to ensure that future
generations do not disproportionately suffer from climate change impacts?
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Ecological Justice: What does the nonhuman world deserve?
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Compensatory Justice: How should monetary and technological resources be
redistributed to compensate those who shoulder disproportional burdens?
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Procedural Justice: How should responsibilities about what to do be defined and
delegated?
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Participatory Justice: Who gets to delegate the responsibilities and decide what to do
and how it should be done?
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Restorative or Transformative Justice: How can responses to climate change be
used to restore or transform what is fundamentally wrong with North-South and other
political, economic, and social relations?
Some Possibilities for Burden-Sharing
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Historical Responsibility: Each country’s GHG reductions depend on its
relative contribution to the problem of climate change. Also know as polluter
pays or beneficiaries pay.
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Common but Differentiated Responsibility: All people bear a common
responsibility reduce GHG emissions, but the greatest burden falls to those
with the ability to pay and to those who have benefitted the most from GHGproducing activities.
Solvency: Costs are distributed among states according to their ability to
pay and their contribution to the problem of climate change.
Grandfathering: The world’s wealthier nations make efforts to reduce their
GHG emissions relative to a baseline year.
Per Capita (Equal Entitlements): Specify the size of the emissions budget,
and allow for every global citizen to be allocated an equal entitlement to the
atmosphere, with rich countries contracting their annual GHG budgets and
poor countries increasing their annual GHG budgets to eventually converge
with the rich nations.
Some More Possibilities for Burden-Sharing
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Securing Basic Needs: Countries emitting more than what is deemed
“reasonable” to support a consistent, modest standard of living accept far
higher mitigation costs than countries facing more poverty.
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Compensatory Equity: Powerless, disadvantaged, and socioeconomically
vulnerable people who are worst affected by climate change are
compensated by those who have benefitted the most from GHG producing
activities.
Focus on the Poor: Relative to climate change, improve the situation of the
poorest countries of the South, with the long-range intention of mitigating
unequal distributions of wealth.
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Carbon Intensity: Stabilize the climate as cost-effectively as possible while
maximizing global economic growth.
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Performance: Countries who use energy more efficiently are rewarded with
more benefits.
http://vimeo.com/3353504