Transcript Atmosphere fullx - Cabarrus County Schools

Atmosphere and Wind
Ch 17: 462-468
The atmosphere
• Atmosphere = the thin layer of gases around Earth
- Provides oxygen
- Absorbs radiation and moderates climate
- Transports and recycles water and nutrients
- 78% N2, 21% O2
• Minute concentrations of permanent (remain at stable
concentrations) gases
- Variable gases = varying concentrations across time
and place
• Human activity is changing the amount of some gases
- CO2, methane (CH4), ozone (O3)
The atmosphere’s composition
The first two layers of the atmosphere
• Troposphere = bottommost layer (11 km [7 miles])
- Air for breathing, weather
- The air gets colder with altitude
- Tropopause = limits mixing between troposphere and the
layer above it
• Stratosphere = 11–50 km (7–31 mi) above sea level
- Drier and less dense, with little vertical mixing
- Becomes warmer with altitude
- Contains UV radiation-blocking ozone, 17–30 km (10–19
mi) above sea level
• The troposphere and stratosphere together make up the lower
atmosphere
- 99% of all atmospheric air is found here
The two highest levels of the atmosphere
• Mesosphere = 50–80 km (31–56 mi) above sea level
- Extremely low air pressure
- Temperatures decrease with altitude
• Thermosphere = atmosphere’s top layer
- Extends upward to 500 m (300 mi)
The atmosphere’s four layers
• Atmospheric layers
have different
- Temperatures
- Densities
- Composition
Solar energy heats the atmosphere
• Energy from the sun:
- Heats and moves air
- Creates seasons
- Influences weather
and climate
• Solar radiation is highest
near the equator
• The spatial relationship between the Earth and sun
determines how much solar energy strikes the Earth
• Microclimate = a localized pattern of weather conditions
Solar energy creates seasons
• Because the Earth is tilted, each hemisphere tilts
toward the sun for half the year
- Results in a change of seasons
Equatorial regions are
unaffected by this tilt, so
days average 12 hours
throughout the year
Air masses produce weather
• Front = the boundary between
air masses that differ in
temperature, moisture, and
density
• Warm front = boundary
where warm, moist air
replaces colder, drier air
• Cold front = where colder,
drier air displaces warmer,
moister air
Warm fronts produce
light rain
Cold fronts produce
thunderstorms
Air masses have different pressures
• High-pressure system = air that descends because it is
cool
- It spreads outward as it nears the ground
- Brings fair weather
• Low-pressure system = warm air rises and draws air
inward toward the center of low pressure
- Rising air expands and cools
- It brings clouds and precipitation
Thermal (temperature) inversion
• Air temperature decreases as altitude increases
- Warm air rises, causing vertical mixing
• Thermal inversion = a layer of
cool air occurs beneath warm
air
• Inversion layer = the band of
air where temperature rises with
altitude
- Denser, cooler air at the
bottom of the layer resists
mixing
Atmospheric inversions
• Persistent atmospheric
inversions in an area with
smoke from forest fires
cause the smoke to be
trapped, impairing air
quality for several days
• Inversions are commonly
found in large cities
surrounded by hills and
mountains
- Examples:
- Los Angeles, Mexico City,
Mumbai, Vancouver
Storms pose hazards
• Atmospheric conditions can produce dangerous storms
• Hurricanes = form when winds rush into areas of low
pressure
- Warm, moist air over the topical oceans rises
• Typhoons (cyclones) = winds turn counterclockwise in
the Northern Hemisphere
- Drawing up huge amounts of water vapor which fall as
heavy rains
• Tornadoes = form when warm air meets cold air
- Quickly rising warm air forms a powerful convective
current (spinning funnel)
Hurricanes and tornadoes
• Understanding how the atmosphere works helps us to:
- Predict violent storms and protect people
- Comprehend how pollution affects climate,
ecosystems, and human health
Climate
Ch 18: 49-504
The atmosphere drives weather and climate
• Weather and climate involve the physical properties of
the troposphere
- Temperature, pressure, humidity, cloudiness, wind
• Weather = specifies atmospheric conditions over short
time periods and within small geographic areas
• Climate = patterns of atmospheric conditions across
large geographic regions over long periods of time
• Mark Twain said, “Climate is what we expect; weather
is what we get”
Solar energy causes air to circulate
• Air near Earth’s surface is
warm and moist
• Convective circulation =
less dense, warmer air rises
- Creating vertical currents
- Rising air expands and
cools
- Cool air descends and
becomes denser
- Replacing rising warm
air
Convection influences
weather and climate
Circulation systems produce climate patterns
• Convective currents contribute to climatic patterns
• Hadley cells = convective cells near the equator
- Surface air warms, rises, and expands
- Causing heavy rainfall near the equator
- Giving rise to tropical rainforests
• Currents heading north and south are dry
- Giving rise to deserts at 30 degrees
• Ferrel cells and polar cells = lift air and create
precipitation at 60 degrees latitude north and south
- Conditions at the poles are dry
Global wind patterns
• Atmospheric cells interact with Earth’s rotation to
produce global wind patterns
- As Earth rotates, equatorial regions spin faster
• Coriolis effect = the apparent north-south deflection of
air currents of the convective cells
- Results in curving global wind patterns called the
doldrums, trade winds, and westerlies
Cold,
dry air
falls
Cell 3 North
Polar cap
Arctic tundra
Evergreen
coniferous forest
60°
Temperate deciduous
forest and grassland
Desert
30°
Cell 2 North
Cool, dry
air falls
Cell 1 North
Tropical deciduous forest
0°
Equator
Tropical
rain forest
Tropical deciduous forest
Cell 1 South
30°
60°
Desert
Temperate deciduous
forest and grassland
Cool, dry
air falls
Cell 2 South
Polar cap
Cold,
dry air
falls
Relationship
between
global air
circulation
and biomes
Moist air rises — rain
Moist air rises — rain
Cell 3 South
Moist
air rises,
cools, and
releases
moisture
as rain
Direct measurements tell us about the present
• We document daily fluctuations in weather
- Precise thermometer measurements over the past 100
years
• Measuring of ocean and
atmospheric chemistry began
in 1958
• Precise records of historical
events
- Droughts, etc.
Atmospheric CO2
concentrations have increased
from 315 ppm to 389 ppm
Proxy indicators tell us about the past
• Paleoclimate = climate of the geological past
• Gives a baseline to compare to today’s climate
• Proxy indicators = indirect evidence that serve as
substitutes for direct measurements
- Shed light on past climate
- Ice caps, ice sheets, and glaciers hold clues to Earth’s
climate history
- Trapped bubbles in ice cores provide a timescale of:
- Atmospheric composition, greenhouse gas
concentrations, temperature trends
- Snowfall, solar activity, and frequency of fires
Ice cores from Antarctica
• Ice cores let us go back in time 800,000 years
- Reading Earth’s history across eight glacial cycles
More proxy indicators
• Cores in sediment beds preserve pollen grains and
other plant remnants
• Tree rings indicate age, precipitation, droughts, and fire
history
• In arid regions, packrats carry seeds and plants to their
middens (dens)
- Plant parts can be preserved for centuries
• Researchers gather data on past ocean conditions from
coral reefs
• Scientists combine multiple records to get a global
perspective
Models help us predict the future
• Climate models = programs
combine what is known about:
- Atmospheric and ocean
circulation
- Atmosphere–ocean
interactions
- Feedback mechanisms
Models simulate climate processes to accurately
predict climate change
Results from three simulations
• Figure (a) shows natural climate
factors only
- Volcanoes
• Figure (b) shows only human
factors
- Greenhouse gas emissions
• Figure (c) shows both factors
Current and future trends and impacts
• Evidence that climate conditions have changed since
industrialization is everywhere
- Fishermen in the Maldives, ranchers in Texas,
homeowners in Florida, etc.
• Scientific evidence that climate has changed is
overwhelming and indisputable
• Intergovernmental Panel on Climate Change (IPCC)
was established in 1988
- Composed of hundreds of international scientists and
government officials
The IPCC’s fourth assessment report (2007)
• The IPCC reports on the synthesis of scientific
information concerning climate change
- Global consensus of scientific climate research
- Summarized thousands of studies
• Documented observed trends in surface temperature,
precipitation patterns, snow and ice cover, sea levels,
storm intensity, etc.
• Predicted impacts of current and future climate change on
wildlife, ecosystems, and human societies
• Discussed strategies to pursue in response to climate
change
Greenhouse Gases
Ch 18: 495-499
The sun and atmosphere keep Earth warm
• Four factors exert the most influence on climate
• The sun = without it, Earth would be dark and frozen
- Supplies most of Earth’s energy
• The atmosphere = without it, Earth’s temperature would
be much colder
• The oceans = shape climate by storing and transporting
heat and moisture
• How Earth spins, tilts, and moves through space
influence how climate varies over long periods of time
The Greenhouse Effect
The Earth’s surface receives energy from
two sources: the sun & the atmosphere
• As a result, the Earth’s surface is
~33C warmer than it would be
without an atmosphere
• This natural process is called the
Greenhouse Effect
Greenhouse gases warm the lower
atmosphere
• As Earth’s surface absorbs solar radiation, the surface
increases in temperature and emits infrared radiation
• Greenhouse gases = atmospheric gases that absorb
infrared radiation
- Water vapor, ozone, carbon dioxide, nitrous oxide,
methane, halocarbons [chlorofluorocarbons (CFCs)]
• After absorbing radiation, greenhouse gases re-emit
infrared energy, losing some energy to space
• Greenhouse effect = energy that travels downward,
warming the atmosphere and the planet’s surface
The greenhouse effect is natural
• Greenhouse gases have always been in the atmosphere
• We are not worried about the natural greenhouse effect
- Anthropogenic (human made) intensification is of
concern
• Global warming potential = the relative ability of one
molecule of a greenhouse gas to contribute to warming
- Expressed in relation to carbon dioxide (potential = 1)
- Methane is 25 times as potent as carbon dioxide
Greenhouse Gases
• Burning fossil fuels and biomass are the major sources of increased
carbon dioxide in the environment
• Major greenhouse gases
– Water Vapor
– Carbon Dioxide
– Methane
– Nitrous Oxide
– Chlorofluorocarbons
– Ozone
Greenhouse Gas
Global
Warming
Potential
Major Source
Remediation or Reduction
Water Vapor
H2O
2
Natural, but heating the
env. increases rate of
evap.
Non-human, so not much to do
Carbon
Dioxide CO2
1
Burning fossil fuels
Moving to alternative energy sources,
carbon sequestering
Methane
CH4
20
Livestock, anaerobic
respiration from landfills
and swamps
Capture, compress, and burn as a
natural gas. Reducing emissions
would have an immediate effect
Nitrous Oxide
N2O
300
High temperature
combustion, especially in
cars
Electric or hybrid cars
Chlorofluorocarbons
CFCs
6500
Purely anthropogenic—
not natural. Found in
fridges
Currently banned. Even though no
more are being made, they persist for
100s of years
Ozone
O3
Potent
Smog resulting from cars, Reduce emissions of smog-causing
industrial pollution,
gases by using scrubbers on
burning biomass
smokestacks and cars
Selected Greenhouse Gases
•
Carbon Dioxide (CO2)
• Source: Fossil fuel burning, deforestation
•
Anthropogenic increase: 30%
•
Average atmospheric residence time: 500 years
•
Methane (CH4)
• Source: Rice cultivation, cattle & sheep ranching, decay
from landfills, mining
•
Anthropogenic increase: 145%
•
Average atmospheric residence time: 7-10 years
•
Nitrous oxide (N2O)
• Source: Industry and agriculture (fertilizers)
•
Anthropogenic increase: 15%
•
Average atmospheric residence time: 140-190 years
Carbon dioxide is of primary concern
• It is not the most potent greenhouse gas, but it is
extremely abundant
- The major contributor to the greenhouse effects
• CO2 exerts 6x more impact than methane, nitrous oxide,
and halocarbons combined
• Deposition, partial decay, and compression of organic
matter (mostly plants) in wetlands or marine areas led to
formation of coal, oil, and natural gas
- These deposits remained buried for millions of years
What caused levels of CO2 to increase?
• Burning fossil fuels transfer CO2 from lithospheric
reservoirs into the atmosphere
- The main reason atmospheric carbon dioxide
concentrations have increased so dramatically
• Deforestation contributes to rising atmospheric CO2
- Forests serve as reservoirs for carbon
- Removing trees reduces the carbon dioxide absorbed
from the atmosphere
• Human activities increased atmospheric CO2 from 280
parts per million (ppm) to 389 ppm
- The highest levels in more than 800,000 years
Other greenhouse gases add to warming
• Methane = fossil fuels, livestock, landfills, crops (rice)
- Levels have doubled since 1750
• Nitrous oxide = feedlots, chemical manufacturing plants,
auto emissions, and synthetic nitrogen fertilizers
• Ozone levels have risen 36% due to photochemical smog
• Halocarbon gases (CFCs) are declining due to the
Montreal Protocol
• Water vapor = the most abundant greenhouse gas
- Contributes most to the natural greenhouse effect
- Concentrations have not changed
The importance of methane (CH4)
• 23 times more powerful as a greenhouse gas than CO2
• The livestock sector is a major player, which accounts
for 35-40% global anthropogenic emissions of methane
(their burps!)
- The livestock sector is responsible for 18% of total
greenhouse gas emissions
• Therefore, consuming less meat can help reduce global
warming more than not driving cars.
U.S. emissions of major greenhouse gases
Feedback complicates our predictions
• Tropospheric warming will transfer more water to the air
- But the effects are uncertain
• A positive feedback loop = more water vapor … more
warming … more evaporation … more water vapor …
• A negative feedback loop = more water vapor … more
clouds … shade and cool Earth OR increase evaporation
• Minor modifications of the atmosphere can lead to major
effects on climate
Most aerosols exert a cooling effect
• Aerosols = microscopic droplets and particles
- They have either a warming or a cooling effect
• Soot (black carbon aerosols) causes warming by
absorbing solar energy
- But most tropospheric aerosols cool the atmosphere
by reflecting the sun’s rays
• Sulfate aerosols produced by fossil fuel combustion may
slow global warming, at least in the short term
- Volcanic eruptions reduce sunlight reaching Earth’s
surface and cool the Earth
Ozone
Ch 17: 79-482
Ozone in the atmosphere
• Ozone (O3) forms under the
effect of UV light in the
stratosphere
• Ozone can also form in the
troposphere
- It forms naturally from
volcanic activity
- It is produced by motor
vehicles so it is a
pollutant
- Sunlight acts on NOx to
produce O3
Stratospheric Ozone
• The ozone in the
stratosphere acts as
“Global sunscreen,”
keeping about 95% of the
sun’s harmful UV
radiation from reaching
the earth’s surface.
- So, stratospheric
ozone is beneficial
- Tropospheric ozone is
harmful
Synthetic chemicals deplete stratospheric
ozone
• Ozone layer = ozone in the lower stratosphere
- Blocks incoming ultraviolet (UV) radiation
- Protecting life from radiation’s damaging effects
• Ozone-depleting substances = human-made chemicals
that destroy ozone by splitting its molecules apart
- Halocarbons = human-made compounds made from
hydrocarbons with added chlorine, bromine, or
fluorine
- Chlorofluorocarbons (CFCs) = a halocarbon used as
refrigerants, in fire extinguishers, in aerosol cans, etc.
- Releases chlorine atoms that split ozone
The Ozone Layer
• Ozone is an unstable gas that
rapidly breaks down
- The ozone layer is only a
few cm thick
- If the rate of breakdown
is faster than the rate of
formation the ozone
layer thins, this could
develop into hole
- A hole in the Antarctic
was first observed in
1985
OZONE DEPLETION IN THE
STRATOSPHERE
 Since 1976, in Antarctica, ozone levels have markedly
decreased during October and November.
 Each winter, steady winds blow in a circular pattern
over Earth’s poles causing a huge mass of cold air that
circulates over Antarctica and isolates its air from the
rest of the atmosphere until the sun returns
◦ Water entering this frigid air freezes, locking CFCs in water
ice crystals that are released and cause their reactions when the
sun returns
◦ Huge masses of ozone-depleted air then flow over Australia,
New Zealand, South America, and South Africa
 Can raise UV-B levels by up to 20%
 Some thing happens to a lesser extent over the Arctic
region
CFCs destroy ozone
• CFCs are inert (don’t react)
• CFCs remain in the
stratosphere for a century
• UV radiation breaks CFCs
into chlorine and carbon
atoms
• The chlorine atom splits
ozone
One chlorine atom can
destroy 100,000 ozone
molecules
The cause of the hole
• Chlorofluorocarbons (CFCs)
• CFCs are odorless and stable.
• CFCs are nonflammable, nontoxic, and
noncorrosive.
- The breakdown under the effect of UV light to
release chlorine radicals (Cl), especially under
cold conditions
- The chlorine atom react with O3 converting it to
O2 and ClO
© 2007 Paul Billiet ODWS
Causes
• Most CFCs are not used in developed countries or will
mostly phased out by 2020
- Phase out dates are later for developing countries
The current situation
• The holes developing over
the pole suggest that they
may be showing an
improvement
- CFC molecules take 30
years to rise up to the
stratosphere
- The chlorine radicals
last a long time
- The peak ozone damage
was supposed to be in
2000
- Damage could go on
another 50 years
Effects of Ozone Depletion
• Human health
• Worse sunburn, eye cataracts,
skin cancers, immune system
suppression
• Food and forests
• Reduced crop yields, reduced
seafood supplies from reduced
phytoplankton, decreased forest
productivity from UV-sensitive
trees
• Wildlife
• Increased eye cataracts,
decreased population of UVsensitive aquatic species,
reduced population of surface
phytoplankton, disrupted aquatic
food webs from phytoplankton
reduction
Effects of Ozone Depletion
• Air Pollution and Materials
- Increased acid rain and smog
(reactions accelerated by highenergy UV radiation)
- Degradation of outdoor paints
and plastics
• Global warming
- Accelerated warming because
of decreased ocean uptake of
carbon dioxide from
atmosphere by phytoplankton
and CFCs acting as
greenhouse gases
What can be done?
• Reduce the use of CFCs
- They are already banned in aerosols (1987)
- BUT they are still used as refrigerants
- Recycle fridges and air conditioning units
The Montreal Protocol
• Montreal Protocol = 196 nations agreed to cut CFC
production in half by 1998
• Follow-up agreements deepened cuts, advanced
timetables, and addressed other ozone-depleting
chemicals
- Industry shifted to safer, inexpensive, and efficient
alternatives
• Challenges still face us
- CFCs will remain in the stratosphere for a long time
- Nations can ask for exemptions to the ban
The Montreal Protocol is a success
• It is considered our biggest environmental success story
• Research developed rapidly, along with technology
• Policymakers included industry in helping solve the
problem
• Implementation of the plan allowed an adaptive
management strategy
- Strategies responded to new scientific data,
technological advances, and economic figures
• The Montreal Protocol can serve as a model for
international environmental cooperation
Protecting the ozone layer
International agreements
reduced ozone-depleting
substances
The hole in the ozone has
stopped growing
Climate Change, pt 1
Ch 18: 504-512
What is climate change?
• Climate change is the fastest-developing area of
environmental science
• Climate = an area’s long-term atmospheric conditions
- Temperature, moisture, wind, precipitation, etc.
- Weather = short-term conditions at localized sites
• Global climate change = describes trends and
variations in Earth’s climate
- Temperature, precipitation, storm frequency
• Global warming and climate change are not the same
Natural Climate Change
• Main alterations in the climate come from
volcanic eruptions, changes in solar input,
moving continents, meteor strikes, and
other factors
• Over the past 1,000 years, the Earth has
experienced fairly stable temperatures, with
a rise becoming noticeable during the last
century
• Major hypotheses about changing climate:
- Change in the Earth’s elliptical orbit about every
100,000 years
- Change due to tilt on Earth’s axis every 40,000 years
- Ice ages could have been caused by wobbling of
Earth on its axis (every 26,000 years)
- 11-year sunspot cycles and 22-year solar magnetic
cycles
Ocean circulation influences climate
• Ocean circulation = ocean water exchanges heat with
the atmosphere,
- Currents move energy from place to place
• The ocean’s thermohaline circulation system affects
regional climates
- Moving warm tropical water north, etc.
- Greenland’s melting ice sheet will affect this flow
• El Niño–Southern Oscillation (ENSO)
- Shifts atmospheric pressure, sea surface
temperature, ocean circulation in the tropical Pacific
Milankovitch cycles influence climate
• Milankovitch cycles = periodic
changes in Earth’s rotation and
orbit around the sun
- Alter the way solar radiation
is distributed over Earth
• These cycles modify patterns of
atmospheric heating
- Triggering climate variation
- For example, periods of cold
glaciation and warm
interglacial times
Solar output and ocean absorption influence
climate
• Solar output = the sun varies in the radiation it emits
- Variation in solar energy (e.g., solar flares) has not
been great enough to change Earth’s temperature
- Radiative forcing is 0.12 watts/m2 – much less than
human causes
• Ocean absorption = the ocean holds 50 times more carbon
than the atmosphere
- Slowing global warming but not preventing it
• Warmer oceans absorb less CO2
- A positive feedback effect that accelerates warming
How might changes in reflectivity affect
atmosphere temperatures?
• The Ice Albedo Feedback System
- Different parts of earth’s surface
vary in their albedo (ability to
reflect light)
- White snow and ice reflect most
sunlight (high albedo), land and
water absorb sunlight (low
albedo)
- Albedo increases when polar ice
caps expand during glacial
periods and decrease when they
melt
- A positive ice albedo feedback
could accelerate global warming
Global warming
• Global warming = an increase in Earth’s average
temperature
- Only one aspect of climate change
• Climate change and global warming refer to current
trends
- Earth’s climate has varied naturally through time
• The current rapid climatic changes are due to humans
- Fossil fuel combustion and deforestation
• Understanding climate change requires understanding
how our planet’s climate works
Global Warming vs. Ozone Depletion
Global Warming
Ozone Depletion
Layer of
Atmosphere
Troposphere
Stratosphere
Substances involved
CO2, CH4, N2O
O3, O2, CFC’s
Problem
Increasing greenhouse gases
CFC’s released—decreases 03
concentration
Consequence
Changes in climate, water
supplies, sea level
Increased incidence of skin cancer,
eye cataracts, damage to crops
Response
Decrease fossil fuel use and
deforestation
Eliminate CFC’s and other ozonedepleting compounds
Temperatures continue to increase
• Average surface temperatures increased 0.74 °C since
1906
- Most of the increase occurred in the last few decades
- Extremely hot days have increased
- The 16 warmest years on record have been since 1990
The future will be hotter
• In the next 20 years, temperatures will rise 0.4 °C
• At the end of the 21st century, temperatures will be 1.8–
4.0 °C higher than today’s
- We will have unusually hot days and heat waves
• Polar areas will have the most intense warming
• Sea surface temperatures will rise
• Hurricanes and tropical storms will increase
- In power and duration
Precipitation is changing, too
• Some regions are receiving more precipitation than
usual, and others are receiving less
• Droughts have become more frequent and severe
- Harming agriculture, promoting soil erosion,
reducing water supplies, and triggering fires
• Heavy rains contribute to flooding
- Killing people, destroying homes, and inflicting
billions of dollars in damage
Projected changes in precipitation
Precipitation will increase at high latitudes and
decrease at low and middle latitudes
Melting snow and ice
• Mountaintop glaciers are disappearing
- Glaciers on tropical mountaintops have disappeared
- The remaining 26 of 150 glaciers in Glacier National
Park will be gone by 2020 or 2030
- Reducing summertime water supplies
• Melting of Greenland’s Arctic ice sheet is accelerating
• Warmer water is melting Antarctic coastal ice shelves
- Interior snow is increasing due to more precipitation
• Melting ice exposes darker, less-reflective surfaces,
which absorb more sunlight, causing more melting
Worldwide, glaciers are melting rapidly
• Nations are rushing to exploit underwater oil and mineral
resources made available by newly opened shipping lanes
• Permafrost (permanently frozen ground) is thawing
- Destabilizing soil, buildings, etc. and releasing methane
Rising sea levels
• Runoff from melting glaciers and ice will cause sea
levels to rise
• As oceans warm, they expand
- Leading to beach erosion, coastal floods, and
intrusion of salt water into aquifers
Coastal areas will flood
An earthquake caused the
2004 tsunami (tidal wave)
that killed 100 Maldives
residents and caused $470
million in damages
• Storm surge = temporary, localized rise in sea level
- Caused by the high tides and winds of storms
• Cities will be flooded
- 53% of people in the U.S. live in coastal areas
Rising sea levels will devastate coasts
• 1 million acres of Louisiana’s wetlands are gone
- Rising sea levels eat away vegetation
- Dams upriver decrease siltation
- Pollution from the Deepwater Horizon
• Millions of people will be displaced from coastal areas
Coral reefs are threatened
• Coral reefs are habitat for food fish
- Snorkeling and scuba diving sites for tourism
• Warmer waters contribute to coral bleaching
- Which kills corals
• Increased CO2 is acidifying the ocean
- Organisms can’t build their exoskeletons
• Oceans have already decreased by 0.1 pH unit
- Enough to kill most coral reefs
Central Case: Rising seas may flood the
Maldives
• Tourists think the Maldives Islands are a paradise
• Rising seas due to global climate change could
submerge them
- Erode beaches, cause
flooding
- Damage coral reefs
• Residents have evacuated the
lowest-lying islands
• Small nations are not the cause
of climate change, yet they
suffer
Climate Change, pt 2
Ch 18: 512-
Climate change affects organisms and
ecosystems
• Organisms are adapted to their environments
- They are affected when those environments change
• Global warming modifies temperature-dependent
phenomena (e.g., timing of migration, breeding)
• Animals and plants will move toward the poles or
upward in elevation
- 20–30% of species will be threatened with extinction
- Rare species will be pushed out of preserves
• Droughts, fire, and disease will decrease plant growth
- Fewer plants means more CO2 in the atmosphere
Climate change affects people
• Societies are feeling the impacts of climate change
• Agriculture: shortened growing seasons, decreased
production, crops more susceptible to droughts
- Increasing hunger
• Forestry: increased fires, invasive species
- Insect and disease outbreaks
• Health: heat waves and stress can cause death
- Respiratory ailments, expansion of tropical diseases
- Disease and sanitation problems from flooding
- Drowning from storms
Climate change affects economics
• Costs will outweigh benefits of climate change
• It will widen the gap between rich and poor
- Those with less wealth and technology will suffer most
• External costs of damages will be $10–350/ton of carbon
• It will cost 1–5% GDP on average globally
- Poor nations will lose more than rich ones
• The Stern Review predicts it will cost 5–20% of GDP by
2200
- Investing 1% of GDP now could avoid these costs
Impacts will vary regionally
• Where we live will determine how we experience the
impacts of climate change
• Temperature changes have been greatest in the Arctic
- Melting ice sheets, thinning ice, increasing storms, etc.
- Harder for people and polar bears to hunt
• U.S. temperatures will continue rising
- Plant communities will shift north and upward
- More frequent extreme weather events
• The southern U.S. will get drier, the northern wetter
- Sea levels will rise and may be worse in the East
The U.S. Global Change Research Program
• In 2009, scientists reported and predicted:
- Temperature increases
- Worse droughts and flooding
- Decreased crop yields
- Water shortages
- Health problems and diseases
- Higher sea levels, beach erosion, destroyed wetlands
- Drought, fire, and pests will change forests
- More grasslands and deserts, fewer forests
- Undermined Alaskan buildings and roads
Predictions from two climate models
By 2050, Illinois will
have a climate like
Missouri’s
By 2090, it will have a
climate like Louisiana’s
Are we responsible for climate change?
• Scientists agree that increased greenhouse gases are
causing global warming
- Burning fossil fuels is increasing greenhouse gases
• In 2005, scientists from 11 nations issued a joint
statement urging political leaders to take action
• There is a broad and clear scientific consensus that
climate change is a pressing issue
- But many people deny what is happening
• People will admit the climate is changing
- But doubt we are the cause
Climate Change and Human Activities
• Humans have been emitted CO2 and
CH4 from agriculture for over 11,000
years
- Began increasing 8,000 ya during
periods of slash-and-burn clearing
and development; cultivating
methane-producing animals
- Continued increase when flooding
lowlands for rice growth
- Ruddiman (2005) estimated that
those activities interrupted what
should have been a global cooling
cycle that would be in effect today
(usually follows interglacial
period)
Climate Change and Human Activities
• Since the industrial revolution (1750) there has been a
sharp rise in
- use of fossil fuels (release CO2 and CH4)
- deforestation and clearing of grasslands to raise
crops (release CO2 and N2O)
- cultivation of rice in paddies and use of inorganic
fertilizers (release N20)
• The two largest contributors to CO2 emissions are
coal burning power plants and vehicles
The debate over climate change is over
• Conservative think tanks and industry-sponsored
scientists cast doubt on the scientific consensus
• The news media tries to present two sides to an issue
- But the sides’ arguments are not equally supported by
evidence
• Most Americans accept that fossil fuel consumption is
changing the planet
• Al Gore’s An Inconvenient Truth helped turn the tide
- People who disliked his politics rejected his message
Acid Deposition
Ch 17: 83-486
Acid deposition
• Acid deposition is another transboundary issue
• Acidic deposition = the deposition of acid, or acidforming pollutants from the atmosphere onto Earth’s
surface
• Acid rain = precipitation containing acid
- Rain, snow, sleet, hail
• Atmospheric deposition = the wet or dry deposition on
land of pollutants (mercury, nitrates, organochlorines)
- From automobiles, electric utilities, industrial facilities
Acid Deposition
• Sulfur oxides (SOx), nitrogen oxides
(NOx), and particulates react in the
atmosphere to produce acidic chemicals
that travel long distances before coming
back to the earth.
– Tall smokestacks reduce local
pollution, but can increase regional
pollution.
– Acidic particles remain in the
atmosphere for 2–14 days,
depending on the prevailing winds,
precipitation, and other weather
patterns.
Burning fossil fuels produces acid rain
• Burning fossil fuels releases sulfur dioxide and nitrogen
oxides
- These compounds react with water, oxygen, and
oxidants to form sulfuric and nitric acids
Acid Deposition
• The acidic substances return
to the earth in one of two
forms:
- Wet deposition as acidic
rain, snow, fog, and cold
vapor with a pH less than
5.6
- Dry deposition as acidic
particles
What Ever Happened to Acid Rain?
• In the 1980s, acid rain
received a lot of media
attention.
- Although we don’t
hear about acid rain
as much these days, it
is still a problem that
deserves our
attention.
What is Acid Rain?
How Does it Form?
• Precipitation with a pH
lower than 5.6 is
considered acidic
- SOx and NOx particles can
travel long distances on
wind currents
- By combining with water
vapor, these particles form
acids which fall to the earth
as acid rain
Where do Sulfur Dioxide (SO2) and
Nitrogen Oxide (NOx) Particles Come
From?
• Sulfur dioxide and
nitrogen dioxide
particles are emitted
from utility plants,
especially coal-fed
electric plants
- Cars also emit acid
rain causing pollution
Acid Deposition Effects
• Acid deposition can cause or worsen respiratory disease, attack
metallic and stone objects, decrease atmospheric visibility, and kill
fish.
– Large amounts of money are spent each year to clean and repair
monuments and statues damaged by acid deposition.
– Acid deposition also decreases atmospheric visibility.
– Acidified lakes have fish kill, and aluminum ions are released
into the water by the lower pH (4.5 or less).
– Many lakes in northern Europe and the eastern U.S. have few, if
any, fish due to decreased pH.
Impacts of acid deposition
• Nutrients are leached from topsoil
• Soil chemistry is changed
• Metal ions (aluminum, zinc, etc.) are converted into
soluble forms that pollute water
• Affects surface water and kills fish
• Damages agricultural crops
• Erodes stone buildings, corrodes cars, erases writing on
tombstones
How Does Acid Rain Effect Our Lives?
• Poor forest/crop health due to acidification of soil: acid
rain can kill nutrient-producing microorganisms
How Does Acid Rain Effect Our Lives?
• Acidification of lakes and streams can lead to the death of
aquatic life, such as trout and bass
How Does Acid Rain Effect Our Lives?
• Acidity can leach heavy metals like mercury out of the soil,
causing toxic levels to build up in the fish we eat
Plants and Acid Deposition
• Acid deposition can deplete some soil
nutrients, release toxic ions into soil, and
weaken plants that become susceptible to
other stresses
– Effects of acid deposition on plants is
caused partly by chemical interaction in
the soils.
• Herbivores that eat these plants can
also develop calcium deficiencies.
• Weakened trees are more susceptible
to diseases.
– Acid can also dissolve aluminum,
cadmium, and mercury ions from the soil.
These ions are toxic to plants and animals.
– The mountaintop trees are those that are
most harmed by acidic rain because they
are also growing in thin soils
Downwind Acid Deposition
• Acid deposition is a problem in areas
downwind from coal-burning
facilities and urban areas.
– Some areas have basic compounds
in the soil that act to buffer or
neutralize some acidic deposits.
– Many acid-producing chemicals
generated in one country end up in
other countries due to prevailing
winds.
What else needs
to be done about Acid Rain ?
• In 1990, an amendment to the Clean Air Act called for
reductions in sulfur emissions
- Established an emissions trading program for sulfur
dioxide
- Benefits outweighed costs 40:1
– This proved to be less effective than hoped, as acid
deposition still persists today
– Acid deposition has also increased concentrations of toxic
forms of aluminum in some soil and in lakes and streams.
• It is predicted that an additional 80% reduction in SO2
emissions would be needed to allow northeastern
streams and lakes to recover from the effects of acid
deposition.
• This is largely due to 2 reasons:
1) reductions in sulfur emissions were not great enough
2) there were no reductions in nitrogen emissions which are
also implicated in forming acid rain
What Can be Done
About Acid Rain?
• Prevention:
- Reduce air pollution by
improving energy
efficiency and increasing
renewable resources
- Use natural gas/low sulfur
coal
• Cleanup
- Add lime to neutralize
acidified lakes and soils
The Future
• A number of prevention and control methods can reduce acid
deposition, but they are politically difficult to implement.
– The best approaches are those that reduce or eliminate
emissions of SO2, NOx, and particulates.
– Use of low sulfur coal is both good and bad
• It lowers the amount of SO2 released, but because more
must be burned to generate the same amount of
electricity, it emits more mercury, CO2, and radioactive
particles.
Climate Solutions
Ch 18: 517-525
The Scientific Consensus about Future
Climate Change
• Measured and projected
changes in the average
temperature of the
atmosphere.
• 90-99% probability that
Earth’s temperature will
increase by 2.4-5.4 C
(4.5-9.7 F) by 2100
- IPCC, U.S. National
Academy of Sciences,
American Geophysical
Union have reached
similar projections
2007 Conclusions from the International Panel
on Climate Change
• Warming of the climate system is unequivocal
• Very high confidence that global average net effect of
human activities since 1750 one of warming
• Human-caused warming over last 30 years has likely had
a visible influence on many physical and biological
systems
• Continued GHG emissions at or above current rates
would cause further warming and induce many changes in
the global climate system during the 21st century that
would very likely be larger than those observed during
the 20th century.”
Shall we pursue mitigation or adaptation?
• Most people accept that our planet is changing
- They are searching for solutions
• Mitigation = pursue actions that reduce greenhouse gas
emissions to lessen severity of future climate change
- Energy efficiency, renewable energy, protecting soil,
preventing deforestation
• Adaptation = accept that climate change is happening
- Pursue strategies to minimize its impacts on us
- Seawalls, leaving the area, coping with drought, etc.
• Both are necessary
We need both adaptation and mitigation
• Adaptation: even if we
stopped all emissions,
warming would continue
• Mitigation: if we do nothing,
we will be overwhelmed by
climate changes
The faster we reduce our emissions,
the less we will alter the climate
Electricity generation
A coal-fired,
electricity-generating
power plant
• The largest source of U.S. CO2 emissions
- 70% of electricity comes from fossil fuels
- Coal causes 50% of emissions
• To reduce fossil fuel use:
- Encourage conservation and efficiency
- Switch to cleaner and renewable energy sources
Conservation and efficiency
• We can make lifestyle choices to reduce electricity use
- Use fewer greenhouse-gas-producing appliances
- Use electricity more efficiently
• The EPA’s Energy Star Program rates appliances, lights,
windows, etc. by their energy efficiency
- Replace old appliances with efficient ones
- Use compact fluorescent lights
- Use efficient windows, ducts, insulation, heating and
cooling systems
Sources of electricity
• We need to switch to clean energy sources
- Nuclear power, biomass energy, solar, wind, etc.
• We need to consider how we use fossil fuels
- Switching from coal to natural gas cuts emissions 50%
- Cogeneration produces fewer emissions
• Carbon capture = removes CO2 from power plant
emissions
• Carbon sequestration (storage) = storing carbon
underground where it will not seep out
- Use depleted oil and gas deposits, salt mines, etc.
- We can’t store enough CO2 to make a difference
Carbon Sequestration
•
•
Carbon sequestration is the process of capturing and storing
carbon dioxide emissions
Many different methods available:
- Planting trees that sequester and remove atmospheric carbon
dioxide
- Soil sequestration- plants such as switchgrass can remove
carbon dioxide from the air and store it in the soil
- Reducing emissions of carbon dioxide and nitrous oxide from
the soil- use no-till cultivation and set aside depleted crop
fields
- Remove carbon dioxide from smokestacks- carbon dioxide is
pumped deep underground or injected deep into the ocean
- Problems: expensive, limited amount of carbon dioxide
can be removed, would increase cost of electricity, could
upset global carbon cycle and deep-sea life
Transportation
• 2nd largest source of U.S.
greenhouse gases
- Cars are inefficient
• Ways to help:
- More efficient cars
- Hybrid or electric cars
- Drive less and use
public transportation
- Live near your job, so
you can bike or walk
U.S. public transportation
saves 4.2 billion gallons
of gasoline and 37 million
metric tons of CO2
emissions
We can reduce emissions in other ways
• Agriculture: sustainable land management lets soil store
more carbon
- Reduce methane emissions from rice and cattle
- Grow renewable biofuels
• Forestry: reforest cleared land, preserve existing forests
- Sustainable forestry practices
• Waste management: treating wastewater
- Generating electricity by incinerating waste
- Recovering methane from landfills
• Individuals can recycle, compost, reduce, or reuse goods
Government Role in Reducing Climate
Change
• Could reduce using three major methods:
- Carbon taxes/energy taxes- taxes on each unit of carbon
dioxide emitted by fossil fuels or each unit of fossil fuel burned
- Could offset cost by decreasing taxes on income, labor, and
profits
- Level economic playing field- greatly increase government
subsidies for energy-efficient technologies, carbon-free
renewable energy technologies, carbon sequestration, and
sustainable agriculture
- Reduce subsidies and tax-breaks for non-renewable energy
- Technology transfer- governments of developed countries give
renewable-energy technology to developing countries
Future Implications
• Projected global warming will cost the
world economy more than $300
million annually by 2050
- Implementing strategies might cost more
in the short-term, but would cost less in
the long-term dealing with harmful effects
• Critics say taking measures to combat
global climate change will hurt the
economy too much to be useful
- Problems: do not take into account
savings from using renewable energy
sources, underestimate ability of
marketplace to respond to economic
initiatives, underestimate potential costs
of disasters and disease from climate
change
Preparing for Climate Change
• The world would need a 60% cut in emissions of ghg (greenhouse
gases) to stabilize their concentrations in the troposphere by 2050
• Wise to have some preparation (adaptation strategy)
- Connect wildlife reserves with corridors
- Move hazardous materials storage tanks away from the coast
- Expand existing wildlife reserves toward poles
- Stockpile supply of key foods
- Prohibit new construction in low-lying coastal areas
- Waste less water, and develop crops that need less water
8 Technologies that could save 8 billion tons
of carbon
- Produce more fuel-efficient
-
-
vehicles
Reduce vehicle use
Improve energy-efficiency in
buildings
Develop carbon capture and
storage processes
Triple nuclear power
Increase solar power
Decrease deforestation/plant
forests
Improve soil carbon management
strategies
The FCCC
• U.N. Framework Convention on Climate Change = a
plan to reduce greenhouse gas emissions to 1990 levels by
2000 through a voluntary, nation-by-nation approach
• By the late 1990s, it was clear that the voluntary approach
would not succeed
• Developing nations created a binding international treaty
requiring emission reductions
• The Kyoto Protocol = between 2008 and 2012, signatory
nations must reduce emissions of six greenhouse gases to
levels below those of 1990
The Kyoto Protocol tried to limit emissions
• This treaty took effect in 2005
- After Russia became the 127th nation to ratify it
• The United States will not ratify the Kyoto Protocol
- It requires industrialized nations to reduce emissions
- But it does not require industrializing nations (China
and India) to reduce theirs
• Other countries resent the U.S. because it emits 20% of
the world’s greenhouse gases but won’t take action
- In 2007, one delegate said, “If for some reason you are
not willing to lead...please get out of the way.”
The Copenhagen conference
• The conference in 2009 tried to design a successor treaty
to the Kyoto Protocol
- Nations hoped the U.S., under President Obama,
would participate in a full international agreement
• Obama would not promise more than Congress had
agreed to
• In a last-minute deal, developed nations will help
developing nations pay for mitigation and adaptation
- Nations that reduce deforestation will be rewarded
• Nothing is legally binding and no targets are set
Outdoor Air Pollution
Outdoor air pollution
• Air pollutants = gases and particulate material added to
the atmosphere
- Can affect climate or harm people or other organisms
• Air pollution = the release of pollutants
• Outdoor (ambient) air pollution = pollution outside
- Has recently decreased due to government policy and
improved technologies in developed countries
- Developing countries and urban areas still have
significant problems
Natural Sources pollute:
• Volcanoes
- Release particulate
matter, sulfur dioxide,
and other gases
• Fires
- Fires pollute the
atmosphere with soot
and gases
• Dust Storms
- Wind over arid land
sends huge amounts of
dust into the air, even
across oceans
We create outdoor air pollution
• Air pollution comes from mobile or stationary sources
• Point sources = specific spots where large quantities of
pollutants are discharged (power plants and factories)
• Non-point sources = more diffuse, consisting of many
small sources (automobiles)
• Primary pollutants = directly harmful and can react to
form harmful substances (soot and carbon monoxide)
• Secondary pollutants = form when primary pollutants
interact or react with components of the atmosphere
- Tropospheric ozone and sulfuric acid
Pollutants exert local and global effects
• Residence time = the time a pollutant stays in the
atmosphere
• Pollutants with brief residence times exert localized
impacts over short time periods
- Particulate matter, automobile exhaust
• Pollutants with long
residence times exert
regional or global impacts
- Pollutants causing
climate change or
- ozone depletion
Legislation addresses pollution
• Air Pollution Control Act (1963) funded research and
encouraged emissions standards
• The Clean Air Act of 1970
- Set standards for air quality, limits on emissions
- Provided funds for pollution-control research
- Allowed citizens to sue parties violating the standards
• The Clean Air Act of 1990 strengthened regulations for
auto emissions, toxic air pollutants, acidic deposition,
stratospheric ozone depletion
- Introduced emissions trading for sulfur dioxide
The EPA sets standards
• The EPA sets nationwide standards for emissions and
concentrations of toxic pollutants
• States monitor air quality
- They develop, implement, and enforce regulations
- They submit plans to the EPA for approval
• The EPA takes over enforcement if plans are inadequate
• Criteria pollutants = pollutants that pose especially
great threats to human health
- Carbon monoxide, sulfur dioxide, nitrogen dioxide,
tropospheric ozone, particulate matter, lead
Criteria pollutants: CO and SO2
• Carbon monoxide (CO) = colorless, odorless gas
- Produced primarily by incomplete combustion of fuel
- From vehicles and engines, industry, waste
combustion, residential wood burning
- Poses risk to humans and animals, even in small
concentrations
• Sulfur dioxide (SO2) = colorless gas with a strong odor
- Coal emissions from electricity generation, industry
- Can form acid precipitation
Criteria pollutants: NO2
• Nitrogen dioxide (NO2) = a highly reactive, foul-smelling reddish
brown gas
- Nitrogen oxides (NOx) = formed when nitrogen and oxygen
react at high temperatures in engines
- Vehicles, industrial combustion, electrical utilities
- Contribute to smog and acid precipitation
• Tropospheric ozone (O3) = a colorless gas with a strong odor
- Results from interactions of sunlight, heat, nitrogen oxides, and
volatile carbon-containing chemicals
- A secondary pollutant and a major component of smog
- Participates in reactions that harm tissues and cause respiratory
problems
- The pollutant that most frequently exceeds EPA standards
Criteria pollutants: particulate matter and
lead
• Particulate matter = suspended solid or liquid particles
- Primary pollutants: dust and soot
- Secondary pollutants: sulfates and nitrates
- Damages respiratory tissue when inhaled
- From dust and combustion processes
• Lead = in gasoline and industrial metal smelting
- Bioaccumulates and damages the nervous system
- Banned in gasoline in developed, but not in
developing, countries
Agencies monitor emissions
• State and local agencies monitor, calculate, and report to
the EPA the emissions of these pollutants:
- Carbon monoxide, sulfur dioxide, particulate matter,
lead, and all nitrogen oxides
• Tropospheric ozone has no emissions to monitor
- It is a secondary pollutant
• Agencies monitor volatile organic compounds (VOCs)
= carbon-containing chemicals
- Used and emitted by engines and industrial processes
- VOCs can react to produce ozone
We have reduced air pollution
• Total emissions of the six monitored pollutants have
declined 60% since the Clean Air Act of 1970
- Despite increased population, energy consumption,
miles traveled, and gross domestic product
We reduced emissions and improved the
economy
• Technology and federal
policies
• Cleaner-burning engines and
catalytic converters
• Permit-trading programs and
clean coal technologies reduce
SO2 emissions
• Scrubbers = chemically
convert or physically remove
pollutants before they leave
smokestacks
• Phaseout of leaded gasoline
Toxic substances pose health risks
• Toxic air pollutants = substances that cause:
- Cancer, reproductive defects
- Neurological, developmental, immune system, or
respiratory problems
• The EPA regulates 188 toxic air pollutants from metal
smelting, sewage treatment, industry, etc.
• Include heavy metals, VOCs, diesel, urban hazards
• Clean Air Act regulations helped reduce emissions by
more than 35% since 1990
Industrializing nations suffer increasing
pollution
• Outdoor pollution is getting worse in developing nations
• Factories and power plants pollute
- Governments emphasize economic growth, not
pollution control
• People burn traditional fuels (wood and charcoal)
- And more own cars
• China has the world’s worst air pollution
- Coal burning, more cars, power plants, factories
- Causing over 300,000 premature deaths/year
Pollution in developing nations is high
More people own cars
Smog in Beijing surrounds
an Olympic stadium
Air pollution in China
• The government is trying to decrease pollution
- Shutting down heavily polluting factories and mines
- Phasing out some subsidies for polluting industries
- Installing pollution controls in factories
- Encouraging renewable and nuclear energy
- Mandating cleaner burning fuels
• Air is improving in Beijing but not in other places
• Asian (Atmospheric) Brown Cloud = a 2-mile-thick layer
of pollution over southern Asia
- Decreased plant productivity, increased flooding, etc.
Smog: our most common air quality problem
• Smog = an unhealthy mixture of
air pollutants over urban areas
• Sulfur in burned coal combines
with oxygen to form sulfuric acid
• Industrial (gray air) smog =
industries burn coal or oil
- Regulations in developed
countries reduced smog
• Coal-burning industrializing
countries face health risks
- Coal and lax pollution control
Smog in Donora
killed 21 people
and sickened 6,000
Photochemical (brown air) smog
• Produced by a series of reactions
- Formed in hot, sunny cities surrounded by mountains
• Light-driven reactions of primary pollutants and
atmospheric compounds
- Morning traffic releases NO and VOCs
- Irritates eyes, noses, and throats
• Los Angeles smog kills 3,900/year and costs $28
billion/year
High levels of NO2 cause
photochemical smog to
form a brown haze over
cities
We can reduce smog
• Regulations require new cars to have catalytic converters
• Require cleaner industrial facilities
- Close those that can’t improve
• Financial incentives to replace aging vehicles
- Restricting driving
• Vehicle inspection programs (“smog checks”)
• Reduce sulfur in diesel; remove lead in gasoline
• Electronic pollution indicator boards raise awareness
• But increased population and cars can wipe out advances
Indoor Air Pollution
Ch 17: 486-490
Indoor air pollution
• Indoor air pollution = in workplaces, schools, and homes
- Health effects are greater than from outdoor pollution
• The average U.S. citizen spends 90% of the time indoors
- Exposed to synthetic materials that have not been
comprehensively tested
• Being environmentally prudent can make it worse
- To reduce heat loss and improve efficiency, ventilation
systems were sealed off
- Windows do not open, trapping pollutants inside
Indoor air pollution in the developing world
• Stems from burning wood,
charcoal, dung, crop
wastes with little to no
ventilation
• Fuel burning pollution
causes 1.6 million
deaths/year
- Soot and carbon monoxide
- Pneumonia, bronchitis, lung cancer, allergies,
cataracts, asthma, heart disease, etc.
Tobacco smoke and radon
• The most dangerous indoor pollutants in developed
nations
• Secondhand smoke from cigarettes is very dangerous
- Contains over 4,000 chemical compounds
- Causes eye, nose, and throat irritation
- Smoking has declined in developed nations
• Radon causes 21,000 deaths a year in the U.S.
- A radioactive gas resulting from natural decay of rock,
soil, or water that can seep into buildings
- New homes are being built that are radon resistant
VOCs pollute indoor air
• The most diverse group of indoor air pollutants
- Released by everything from plastics and oils to
perfumes and paints
- Most VOCs are released in very small amounts
• Unclear health implications due to low concentrations
• Formaldehyde leaking from pressed wood and insulation
irritates mucous membranes and induces skin allergies
• Pesticides seep through floors and walls
- Are brought in on shoe soles
Living organisms can pollute indoors
• Dust mites and animal dander worsen asthma
• Fungi, mold, mildew, airborne bacteria cause allergies,
asthma, other respiratory ailments, and diseases
• Building-related illness = a sickness produced by indoor
pollution
• Sick building syndrome = a sickness produced by
indoor pollution with general and nonspecific symptoms
- Reduced by using low-toxicity building materials and
good ventilation
“Sick Building Syndrome”
• EPA studies linked certain pollutants found in buildings
to many negative health effects
– Respiratory problems, irritability and depression,
chronic fatigue, flu-like symptoms, allergic reactions
• The symptoms people report cannot be traced to
any one particular cause
• EPA estimates about 1 in 5 commercial buildings are
“sick buildings,” meaning they expose employees to
health risks from indoor air pollutants
Risks of Sick Building Syndrome
• Different types of buildings
have different associated risks
– Older buildings: asbestos and lead
– Newer buildings: formaldehyde
and other VOCs
– Houses with wood-burning or
kerosene stoves: nitrogen and
carbon oxides
BUILDING OCCUPANTS
• The sensitivity of people to indoor pollutants varies depending on genetic
factors, lifestyle, & age.
• Symptoms also vary as a function of the particular pollutant.
- Some can be fatal under special circumstances (e.g. CO poisoning).
- The problems in sick buildings may be traceable to specific sources,
or they may be unknown
• Sick building syndrome can be brought on by stress from various
sources, even employment-related stress.
Energy conservation and sick building syndrome
• Unfortunately, two of the best
ways to conserve energy in
buildings (increase insulation and
eliminate air leaks) worsens the
problem of indoor air pollution.
- Increasing ventilation is key to
reducing Sick Building
Syndrome, which interferes
with heating/cooling systems
Clean-up
• Increase intake of outside air
• Circulate a building’s air through
rooftop greenhouses
• Use exhaust hoods for stoves and
appliances burning natural gas
• Install efficient chimneys for
wood-burning stoves
Case Study
• Massachusetts Registry of Motor Vehicles.
- Constructed in April 1994, the first problems were
reported in June of the same year.
- These included unpleasant odors, respiratory
problems, eye irritations, rashes and other
symptoms.
• The cooling system condensed water vapor onto ceiling
tiles, which were composed of a starch that fermented
when wet.
- Fire proofing around the ductwork was also wet and
falling apart, releasing fibers into the air.
• The building was closed after 15 months of occupancy.
We can reduce indoor air pollution
• In developed countries:
- Use low-toxicity materials, limit use of plastics and
treated wood, monitor air quality, keep rooms clean
- Provide adequate ventilation
- Limit exposure to known toxicants
- Test homes and offices and use CO detectors
• In developing countries:
- Dry wood before burning
- Cook outside
- Use less-polluting fuels (natural gas)
Economic Solutions, pt 2
Ch 18: 522-526
The toll of air pollution
• Each year, air pollution kills about 3
million people, mostly from indoor
air pollution in developing
countries.
- Air pollution deaths in the U.S.
range from 150,000 to 350,000
people per year.
- A large diesel-powered
bulldozer produces as much
air pollution as 26 cars.
The Results of Clean Air Act
• U.S. citizens insisted that the Clean Air Act be passed and
enforced to improve air quality, and the country was affluent
enough to afford the controls and improvements.
- Negative: we rely more on cleanup rather than prevention.
- Negative: Congress has not increased fuel-efficiency standards for cars,
etc.
- Oceangoing ships have little or no air pollution regulations.
• The Clean Air Acts have not done much to reduce
greenhouse gas emissions.
- Company executives claim that improvements would cost too
much, but these estimates are often too high and
implementation has helped to increase economic growth and
create jobs.
Good news/bad news
• Six criteria air pollutants decreased 48% between 1983 and
2002 even with increased energy consumption, miles traveled,
and population.
- Between 1983 and 2012, emissions from the six major air
pollutants decreased: 93% for lead, 41% for carbon
monoxide, 40% for volatile organic compounds, 34% for
suspended particulate matter, 33% for sulfur dioxide, and
15% for NOx.
• Release of two hazardous air pollutants—mercury and dioxins
has increased in recent years. These are toxic at very low
levels.
- The EPA estimates that about 100 million Americans live
in areas where the risk of cancer from HAPs is 10 times
higher than the accepted standard.
• Smog levels did not drop any between 1993 and 2003 after
dropping in the 1980s.
Will emissions cuts hurt the economy?
• The U.S. Senate feels
emissions reductions will
hurt the economy
• China and India also resist
emissions cuts
• Economic vitality does not
need higher emissions
- Germany cut emissions by 21%, the U.K. by 17%
• Industrialized nations will gain from energy transitions
- They invent, develop, and market new technologies
• The future will belong to nations willing to develop new technologies and energy sources
States and cities are advancing policies
• The U.S. federal government is not taking
action
- State and local governments are
• By 2010, 1,000 mayors signed the U.S.
Mayors Climate Protection Agreement
- To meet or beat Kyoto Protocol guidelines
• California passed the Global Warming Solutions Act
- To cut emissions 25% by 2020
• Regional Greenhouse Gas Initiative
(RGGI) in 2007
- 10 northeastern states
- Set up a cap-and-trade program
Market mechanisms address climate change
• Permit trading programs harness the economic efficiency
of the free market to achieve policy goals
- Businesses have flexibility in how they meet the goals
• Polluters choose how to cut their emissions
- They are given financial incentives to reduce them
Cap-and-trade emissions trading programs
• The approach of the Regional Greenhouse Gas Initiative:
- Each state decides which polluting sources participate
- Each state sets a cap on total CO2 emissions it allows
- Each emissions source gets one permit for each ton
they emit, up to the amount of the cap
- Each state lowers its cap over time
- States with too few permits must reduce emissions,
buy permits from others, or pay for carbon offsets
- Sources with too many permits may sell them
- Any source emitting more than permitted will be
penalized
Cap-and-trade programs already exist
• Chicago Climate Exchange = the world’s first emissions
trading program for greenhouse gas reduction
- 350 corporations, institutions, etc.
- Voluntary but legally binding trading system aims for
a 6% reduction in emissions by 2010
• The European Union Emission Trading Scheme
- The world’s largest cap-and-trade program
- Governments had allocated too many permits
• Permits only work if government policies limit emissions
Problems with Emissions Trading
• The Clear Skies Initiative of 2001 has been
criticized as a way for big polluters to
continue polluting.
- This plan is not a good one for reducing
toxic mercury in the environment.
• In 2002, the EPA reported that the largest and
oldest cap-and-trade program produced less
emissions reductions than projected or that
could be expected.
- There were accounting abuses.
• Environmentalists point to deficiencies:
- Continuing to rely on pollution clean-up
than prevention
- Failing to increase fuel efficiency for cars
- Not adequately regulating emissions
Carbon taxes are another option
• Critics say cap-and-trade systems are not effective
• Carbon tax = governments charge polluters a fee for
each unit of greenhouse gases they emit
- Polluters have a financial incentive to reduce
emissions
- European nations, British Columbia, and Boulder,
Colorado have carbon taxes
• Polluters pass costs on to consumers
• Fee-and-dividend = funds from the carbon tax (fee) are
passed to taxpayers as refunds (dividends)
Carbon offsets are popular
• Carbon offset = a voluntary payment intended to enable
another entity to reduce the greenhouse emissions that one
is unable to reduce oneself
- The payments offset one’s own emissions
• Popular among utilities, businesses, universities,
governments, and individuals
- Trying to achieve carbon-neutrality, where no net
carbon is emitted
• Carbon offsets fall short
- Needs rigorous oversight to make sure that the offset
money accomplishes what it is intended for
Reduce Air Pollution
• Use Scrubbers on smoke stacks
to remove air pollutants
• Improve energy efficiency
• Use Solar/Wind
• Electric Cars can reduce
air pollution if electricity
comes from nuclear/
alternative energy sources
Motor Vehicle Air Pollution
• There are a number of ways to prevent
and control air pollution from motor
vehicles
- Get older, more polluting vehicles
off the road.
- Hybrid-electric vehicles and zeroemission vehicles should reduce
emissions over the next 10–20
years.
- Developing countries are increasing
their air pollution with more
vehicles on the road that are over 10
years old and are without pollution
controls.
Car Emissions
• The EPA has set new fuel
efficiency standards for cars,
effective for models from 20102016
- The average for its cars will
have to be 42 mpg
- Trucks will be 26 mpg by
2016
- If the manufacturers do
not meet these standards,
they will be assessed a $5
fee per vehicle made for
every .1mpg that they're
under the standard for
Power Plants
• Power plants already in existence in 1970 were not required to meet
the new Clean Air Act standards.
- A 1977 rule in the Clean Air Act (New Source Review) requires
older plants to upgrade pollution control equipment when they
expand or modernize the facilities.
- This has been circumvented by calling these expansions
maintenance
- The EPA is setting new standards, which may limit the
opening of new coal plants
Ultrafine Particles
• There is controversy over reducing
emissions of ultrafine particles that pose a
serious threat to human health.
- Fine particles (less than 10 microns)
and ultrafine particles (less than 2.5
microns) are generally not captured by
most air pollution control equipment.
- These particles penetrate the natural
defenses of the respiratory system.
- These particles are estimated to
kill 65,000–200,000 Americans
per year. This number is even
higher in developing countries
(300,000–700,000).
• Costs to implement stricter standards are
estimated at $7 billion/year with health
and other benefits of $120 billion/year.
Indoor Air Pollution
• Indoor air pollution is a
greater threat to human
health, but little effort has
been spent on reducing it.
- In developing countries,
indoor air pollution can be
reduced by use of clay or
metal stoves and venting
to the outside, and by use
of solar cookers in sunny
areas.
- This would also reduce
deforestation.
You can reduce your carbon footprint
• Carbon footprint = expresses the amount of carbon we
are responsible for emitting
• People may apply many strategies to decrease their
footprint
• College students must help drive personal and societal
changes needed to mitigate climate change
• Global climate change may be the biggest challenge
facing us and our children
- With concerted action, we can avert the most severe
impacts
Final Thoughts
• There is a need to focus on
preventing air pollution of
all types in developing
countries.
- At present, there is an
reactionary approach to
controlling pollution.
- We need to shift focus
to preventing air
pollution