Download Atmosphere and Global Climate Change

Atmosphere and Global Climate
Change
Nitrogen (78%)
• Fundamental nutrient for living organisms
• Deposits on Earth through nitrogen fixation
and reactions involving lightening and
precipitation
• Returns to the atmosphere through
combustion of biomass and denitrification.
Oxygen (21%)
• Oxygen molecules are produced through
photosynthesis and are utilized in cellular
respiration
Water Vapor (0-4%)
• Largest amounts occur near the equator, over
oceans and in tropical regions
• Areas where atmospheric water vapor can be
low are polar areas and desert
Carbon Dioxide (<<1%)
• Volume has increased about 25% in the last 300
years because of the burning of fossil fuels
• CO2 is produced through cellular respiration and
the decay of organic matter
• It is a reactant in photosynthesis
• CO2 is also a major greenhouse gas
• Humans are responsible for 5,500 million tons of
CO2 per year
• The average time CO2 molecules stay in the
atmosphere is about 100 years.
Methane (<<<1%)
• Contributes to the greenhouse effect
• Since 1750, methane has increases 150% due
to the use of fossil fuels, mining, landfills,
grazers and flooding of rice fields
• Human activity is responsible for about 400
million tons per year compared with the 200
million tons produced naturally
• Average cycle of a methane molecule in the
atmosphere is about 10 years.
Nitrous Oxide (<<<1%)
• Concentrations have increased about 0.3% per
year.
• Burning fossil fuels, use of fertilizers, burning
biomass, deforestation and conversion to
agricultural land increase concentrations
• Humans are responsible for 6 million tons per
year
• Contributes to the greenhouse effect
• Average time of a N2O molecule in the
atmosphere is about 170 years.
Ozone (<<<1%)
• 97% of the Ozone is found in the stratosphere
• Ozone absorbs UV radiation
• Ozone is produces in the production of
photochemical smog
• A “hole” in the Ozone layer occurs over
Antarctica.
• CFCs are the main cause of the breakdown of
the ozone layer.
Layers of the Atmosphere
• Troposphere: 0-7 miles above surface. 75% of
atmosphere’s mass. Temps decrease with
altitude reaching -76 F near the top. Weather
occurs in this layer
• Stratosphere: Temps increases with altitude
due to absorption of heat by ozone. Ozone is
produced by UV radiation and lightening.
Contains the Ozone Layer.
Layers of the Atmosphere
• Mesosphere: Temps decrease with altitude.
Coldest layer. Ice clouds occur. Meteors burn
up in this layer
• Thermosphere (Ionosphere): Temps increase
with height due to gamma rays, X-rays, and UV
radiation. Molecules are converted into ions
which results in the aurora borealis in the
northern hemisphere and the aurora australis
in the southern hemisphere.
Changes in Temperature in the
Atmosphere
Weather
• Weather is caused by the movement of heat
energy which influences the following physical
properties:
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Temperature
Air pressure
Humidity
Precipitation
Available sunshine determined by cloud cover
Wind speed
Wind direction
Climate
• Describes the total of all weather occurring
over a period of years in a given place
Energy
• Energy can be transferred wherever there is a
temperature difference between two objects.
• Radiation: flow of electromagnetic radiation.
It is the method by which Earth received solar
energy
• Conduction: transferred by the collisions that
take place between heat-carrying molecules
Energy- Convection
• Convection: primary way energy is transferred
from hotter to colder regions in the atmosphere
and the primary determinant of weather patterns
• Involves the movement of warmer and therefore
more energetic air
• Takes place both vertically and horizontally
• When air near the ground becomes warmer and
therefore less dense, the air rises.
• Pressure differences that develop because of
temperature differences result in wind or
horizontal convection.
Energy- Convection
• Regions nearer the equator receive much more
solar energy that near the poles and are much
warmer.
• There latitudinal differences in surface temp
create global-scale flows of energy within the
atmosphere, giving rise to the major weather
patterns of the world.
• Without convection and the transfer of energy,
the equator would be about 27 F warmer and the
Arctic would be about 45 F colder
Evidence for Climate Change
• Comes from data used to measure climate (only aviable for
the last 100 years or so), written accounts (subjective), and
data materials present at the time:
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Tree rings
Gas bubbles trapped in glaciers
Deep ice core samples
Lake sediments
Marine fossils
Sediments
Dust analysis
Isotope ratios in fossilized remains
• Bottom line: the earth has gone through periods of
warming and periods of cooling
Factors the influence climate
• Air Mass: large body of air that has similar
temperature and moisture contents. Can be
categorized as equatorial, tropical, polar, arctic,
continental or maritime
• Air Pressure: Gravity on an air mass results in air
pressure. Air pressure decreases with altitude.
Low pressure usually produces cloudy and stormy
weather. High pressure masses contain cool,
dense air that descends towards the surface and
becomes warmer. High pressure is associated
with fair weather.
Factors the Influence Climate
• Albedo: Reflectivity. Ocean = Low albedo,
Land = moderate albedo. Snow and Ice =
Largest albedo. Dust in the atmosphere has a
positive feedback effect. Dust forms a high
albedo veil around earth so solar radiation is
reflected.
• Altitude: for every 1,000 feet up there is a 3 F
drop in temp. Every 300 feet up is equivalent
to a 62 mile shift in latitude north.
Altitude
Factors the Influence Climate
• Angle of Sun: in the Northern Hemisphere winter,
the earth is closest to the sun. Areas closest to
the equator receive the most sun and therefore
have higher temps.
• Carbon Cycle: Consumption of carbon in the form
of CO2 results in cooling. Consuming CO2 from:
carbonate rock weathering and silicate rock
weathering. Production of CO2 results in
warming. Breakdown of carbonate rocks and
carbonate formation in oceans lead to warming.
Factors the Influence Climate
• Clouds: collections of water drops or ice
crystals suspended in the atmosphere. As
warmer air rises it expands due to decreasing
air pressure and drops in temp- making it rain.
• Distance to Oceans: Oceans are thermally
more stable than landmasses. The specific
heat of water is 5X greater than that of air.
Because of this, changes in temp are more
extreme over land than at sea
Factors the Influence Climate
• Fronts: when 2 air masses meet, the boundary
is called a front. A warm front is a boundary
between an advancing warm air mass and the
cooler one replacing it. Since warm air is less
dense, it rises and cools and the moisture it
contains is released as rain. A cold front is the
leading edge of an advancing cool air mass.
Cold fronts are associated with thunderhead
clouds, high winds and thunderstorms.
Fronts
Factors the Influence Climate
• Greenhouse Effect: most important
greenhouse gasses are: water, carbon dioxide,
and methane. Without the effect the earth
would be too cool to live on
• Heat (Convection): Climate is influenced by
how heat energy is exchanged between air
over the ocean and air over the land
• Land Changes: Climate is influenced by
urbanization and deforestation.
Factors the Influence Climate
• Latitude: higher latitudes mean less solar
radiation
• Location: location of high and low air pressure
zones and where land masses are distributed
• Moisture Content of Air (Humidity): determinant
of plant growth and distribution of biome type.
More water vapor in the air leads to more clouds
and rainfall. Water vapor is also a greenhouse gas
and traps heat energy . The dew point is the
temperature where water condenses.
Factors the Influence Climate
• Mountain Ranges: Rain shadow Effect. Side
facing the ocean is the windward side and
receives the rain. Side opposite the ocean is
the leeward side and is dry. Orographic lifting
occurs when an air mass is forces from low
elevation to a high elevations. As it rises it
expands and cools that can create clouds and
precipitation.
Orographic Lifting/Rain Shadow Effect
Factors that Influence Climate
• Plate Tectonics and Volcanoes: Plate tectonics
affect CO2 (a greenhouse gas). Volcanoes
produce it.
• Pollution: Greenhouse gasses are emitted
from both natural and anthropocentric
sources
• Precession: the wobble of the Earth on its axis
changes the amount of energy received by the
sun
Factors that Influence Climate
• Human Activity: Deforestation, urbanization
and heat island effects, release of pollutants,
burning of fossil fuels and production of acid
rain are factors that affect climate. Increased
pollution alone, combined with an increase in
convectional uplift in urban areas increases
the amount of rainfall as much as 10%
compared to undeveloped areas.
Factors that Influence Climate
• Rotation: Daily temp cycles are primarily
influenced by earths rotation on its axis. At night,
heat escapes. Daily minimum temps occur just
before sunrise
• Solar output: Changes in solar output only 1%
per 100 years would change the temp by 1 F.
Times of sunspot activity correspond to
decreases in solar radiation reaching Earth. The
sun’s magnetic field reverses every 22 years.
Factors that Influence Climate
• Volcanoes: Sulfur-rich volcanic eruptions can
eject material into the stratosphere and cause
troposphereic cooling and stratospheric warming.
They stay in the atmosphere for 1-3 years. Over
the course of millions of years volcanic ash
deposited in oceans can increase iron content in
seawater which can promote biotic activity. But
that decreases CO2 levels in the water and
therefore in the atmosphere result in in global
cooling. Recent research also suggest that large
eruptions may trigger El Nino events.
Factors that Influence Climate
• Wind Patterns: Influenced by temp and pressure differences
(gradients).
• 1. The sun heats the atmosphere unevenly. 2. The air closest
to the surface is warmer and rises 3. Air at higher elevations
cools and sinks- this creates a convection process and is the
primary cause of winds.
• Winds are effected by:
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Uneven heating of the surface
Seasons
The Coriolis Effect
Amount of solar radiation reaching the Earth over a period of time
Convection cells created by areas of warm ocean water which in
turn are caused be differences in water density, winds and earths
rotation.
Factors the Influence Climate
• Winds: During calm sunny days, land warms up faster than
the sea. This causes the air above the land to become more
dense than air above the sea. This creates sea breezes.
• Anabatic Winds: develop in hilly or mountainous areas during
the day, especially if weather is calm and has some sun. In
situations like this, the air around the hilltops becomes
warmer than the air at the same altitude over adjacent
valleys.
• Katabactic Winds: occur on clear still nights when the air that
is in contact with the ground loses heat quickly by radiations
back to space. The result is that the air near the ground over
hill and mountain summits becomes colder than air at that
same altitude over adjacent valleys.
Atmospheric Circulation
• Air closer to the earths surface is the warmest
and rises
• At high elevations air is cooler and much more
dense and sinks
• This sets up a convection process and is the
primary cause of winds
• Global Air Circulation is also affected by:
seasons, the Coriolis Effect, convection cells.
Atmospheric Circulation
• Trade winds are the prevailing pattern of easterly
surface winds found in the tropics, within the
lower portion of the earths atmosphere.
• Trade winds blow mainly from the northeast in
the Northern Hemisphere (northeast trade
winds) and from the southeast in the Southern
Hemisphere (southeast trade winds)
• Trade winds act as the steering flow for tropical
storms that form over the Atlantic, pacific and
south Indian oceans.
Atmospheric Circulation
• Horizontal winds move from areas of high
pressures to areas of low pressures.
• Wind speed is determined by pressure
differences between the air masses
• More pressure= higher wind speed
• Wind direction is based on where the wind is
coming from, wind from the east is called an
easterly.
Atmospheric Circulation
• Earths rotation on its axis
causes winds not to travel
straight- Coriolis Effect
• It causes the prevailing winds
in the Northern Hemisphere
to spiral clockwise from highpressure areas and counter
clockwise from low-pressure
areas.
Hadley Air Circulation Cells
• Air heated near the equator rises and spreads our north and
south
• After cooling in the upper atmosphere it sinks back within
earths surface within the subtropical climate zone (25-49
degrees N and S of the equator)
• The equatorial regions of Hadley Cells are characterized by
high humidity, high clouds and heavy rains
• The subtropical regions of Hadley cells are characterized by
low relative humidity, little cloud formation, high ocean
evaporation and many of the worlds deserts. Warm to hot
summers and mild winters
• The tropical wet and dry (or savanna) climate has a dry
season more than 2 months long. Yearly loss of water through
evaporation exceeds water gains from precipitation
Ferrel Air Circulation Cells
• Form 30-60 degrees north and south of the equator
• The descending winds of Hadley cells diverge as moist
tropical air moves toward the poles with westerly
winds
• Mid latitude climates can have severe winters and cool
summers due to mid-latitude cyclone patterns.
• The climate of this area is governed by both tropical
and polar air masses.
• They have distinct winters and have lots of broadleaf
deciduous and coniferous evergreen forests.
Polar Air Circulation Cells
• Originate as icy cold, dry , dense air
descending from the troposphere to the
ground
• The air meets with warm tropical air from
mid-latitudes.
• Air then returns to the poles, cooling than
sinking. The sinking suppresses precipitations
(thus polar regions are deserts)
• Two major biomes are tundra and taiga.
Hurricanes
• Begin over warm oceans in areas where tread winds
converge
• A subtropical high-pressure zone creates hot day temps
with low humidity that allows for large evaporations.
The Coriolis effect initiates the cyclonic flow
• The cyclonic circulation allows them to pick up
moisture and latent heat energy from oceans
• In the center of the hurricane is the eye, a descending
air and low pressure area
• In 2005, Hurricane Katrina hit New Orleans and was
responsible for 1,830 deaths and $75 billion in damages
Tornadoes
• Swirling masses of air with wind speeds close to
300 mph.
• The center or the tornado is an area of low
pressure
• Diameters of hundreds of meters and are
produced from a single convection storm
• In the US tornado season is April-July
• Because of advances in weather modeling,
forecasting and warning systems, deaths are rare.
Tropical Cyclones
• Diameters of hundreds of meters and
comprised of many convection storms.
• An oceanic phenomenon and die out over
land.
• Lifetimes measured in days.
Monsoons
• Strong and violent winds that change direction with the seasons
• Monsoon winds blow from cold to warm regions because cold air takes up
more space
• India’s climate is dominated by monsoons
• During the Indian winter, which is hot and dry, the monsoon winds blow
from northeast and carry little moisture.
• The temp is high because the Himalayas form a barrier that prevents cold
air from passing onto the subcontinent
• India lies between the Tropic of Cancer and the equator so the suns rays
shine directly on the land
• During the summer monsoons move onto the subcontinent from the
southwest
• The winds carry moisture from the Indian ocean and bring heavy rains from
June to September.
• Farmers in India rely on these torrential summer rainstorms to irrigate their
land
• Large amount of India’s electricity is generated by water power provided by
monsoon rains.
Monsoons in India
Rain Shadow
• A rain shadow is a dry area on the mountainside facing away
from the direction of the wind
• The mountains block the passage of rain-producing weather
systems, casting a “shadow” of dryness behind them
• Warm, moist air rises through orographic lifting on the top of
a mountain range or large mountain, where, due to
decreasing atmospheric pressure with increasing altitude, it
expands and cools reaching its dew point
• At the dew point moisture condenses onto the mountain and
precipitates on the top and windward side of the mountain
• Typically, descending air also gets warmer down the leeward
side of the mountain creating an arid region.
Rain shadow/ orographic lifting
Normal Conditions (El Nino, La Nina)
• During normal conditions, easterly trade winds move water
and air warmed by the sun toward the west (Walker
circulation).
• The ocean is generally around 24 inches higher in the western
Pacific and water about 14 F warmer
• The trade winds, in piling up water in the western Pacific,
make a deep – 450 ft- warm layer in the west that pushes the
thermocline down while it rises in the east
• The shallow -90 ft- eastern thermocline allows the winds to
pull up nutrient rich water from below, increasing fishing
stocks.
• The western side of equatorial pacific is characterized by
warm, wet, low-pressure weather, as the collected moisture is
released in the form of typhoons and thunderstorms.
Normal Conditions (El Nino, La Nina)
El Nino
• When the air pressure patterns In the South Pacific reverse
direction (the air pressure at Australia is higher than at Thaiti), the
trades winds decrease in strength (or reverse).
• The result is that the normal flow of water away from S America
decreases and the ocean water piled up off the coast of S America.
• This pushes the thermocline deeper and decreases the upwelling
of nutrient-rich deep water which results in massive fish kills off
the S American coast
• With a deeper thermocline and decreased westward transport of
water, the surface temp increases in the eastern Pacific
• The net result is a shift of prevailing rain pattern from the normal
western Pacific to central Pacific; rainfall is more common in the
central pacific while the western pacific becomes dry
El Nino
El Nino- Global Effects
La Nina
• When trade winds that blow west across the tropical Pacific
are stronger than normal leading to increased upwelling off S
America and COOLER sea surface temperatures
• Prevailing rain pattern also shifts farther west than normal
• These winds pile up warm surface water in the western Pacific
• Characterized by unusually cold ocean temps in eastern
equatorial Pacific
• Tends to bring opposite effects of El Nino to the US with
wetter than normal conditions across the Pacific NW and
both dryer and warmer condition in the southern states
• Winter temps are warmer than normal in the SE US and
cooler than normal in the NW
• Increased temps in the SE lead to more hurricanes
• La Nina is also responsible for heavier than normal monsoons
in India and SE Asia.
Global Change
10-15% of your APES Exam
Stratospheric Ozone
• Stratosphere contains 97% of Ozone
• Most Ozone is formed over the tropics. However, slow
circulation currents carry the majority of it to the poles,
resulting in the thickest layers over the poles and the thinnest
layers over the tropics
• Formed in the stratosphere by the reaction of UV radiation
striking an oxygen molecule and splitting it into two free
radical Oxygens
• That free molecule reacts with atmospheric ozone to form O3.
• The reverse reaction also happens so generally these
reactions balance each other out keeping the level of ozone
fairly constant
• O + O 2  O3
Ultraviolet Radiation
• UVA- usually causes skin tanning. 1,000X less
effective than UVB in producing skin redness but
more of it reaches the surface than UBV. Many
fruits, flowers seeds and patterns of bird plumage
are only visible in UV light as well as the urine of
some animals.
• UVB- causes blistering sunburns and is associated
with skin cancer
• UVC- found only in the stratosphere and is
responsible for creating Ozone.
Causes of Ozone Depletion
• Thinning of the Ozone layer
was first discovered in 1985
• It occurs seasonally and due
to human made compounds
containing halogens
(chlorine, bromine, fluorine
or iodine)
• Measurements indicate that
ozone over the Antarctic
has decreases about 60%
since the late 1970s with an
average loss of 3% per year.
Causes Of Ozone Depletion
• The main culprits are CFCs
• First manufactured during the 1920s they are
used as refrigerants (Freon), aerosol propellants,
electrical part cleaning solvents and in the
manufacture of foam products and insulation
• By 1974, nearly 1 million tons of CFCs were
produced per year
• The largest source of CFCs to the atmosphere
were from leaking AC units
• The average time of CFCs in the atmosphere is
200 years.
Causes of Ozone Depletion
Causes of Ozone Depletion
• One chlorine atom released from CFCs can destroy over
100,000 ozone molecules
• Much destruction is from CFCs released many years ago
as it takes 8 years for a CFC molecule to reach the
ozone layer
• Bromine, found in much smaller quantities than
chlorine, is about 50X more effective in its effect on
ozone depletion and is responsible for about 20% of
the problem
• Bromine is found in halons, found in fire extinguishers.
Methyl Bromide is used fumigation and agricultures
and is naturally released from phytoplankton and
biomass burning
Effects of Ozone Depletion
• During the onset of the 1998 Antarctic spring, a hole 3X the
size of Australia (over 3,500 miles in diameter) developed in
the ozone layer over the South Pole.
• Stratospheric Ozone protects life from harmful UV radiation.
Harmful effects of increased UV radiation include:
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Increases in skin cancer, sunburns and damage
Increases in cataracts of the eye
Reduction in crop production
Deleterious effects to animals (they don’t wear sunscreen)
Reduction in the growth of phytoplankton and cumulative effect
on food webs
– Cooling of the stratosphere
– Reduction in immune system
– Climate Change
Reducing Ozone Depletion
• Although most developed countries have phased out ozonedestroying chemicals, they are still legal in developing
countries
• 1. HCFC replaces chlorine with hydrogen. Unfortunately, it is
still capable of destroying ozone but less effectively because it
breaks down ozone more in the troposphere
• 2. alternatives to halons can be used in fire extinguishers
• 3. helium, ammonia, propane or butane can be used as a
coolant. Helium-cooled refrigerators use 50% less electricity.
• 4. Use a pump spray instead of aerosol sprays
• 5. Comply with disposal of oil refrigerators and AC units via
instructions from the Clean Air Act.
Relevant Laws and Treaties
• Montreal Protocol (1987): designed to protect the
stratospheric ozone layer. Stipulated that production and
consumption of compounds that deplete ozone in the
stratosphere were to be phased out by 2000
• London (1990): Countries that signed Montreal Protocol met
again in London and decided that a total phase-out of CFCs
was necessary. They agreed this could happen by 2000
• Copenhagen (1992): Phase-out schedule for CFCs was
accelerated, with the industrialized countries agreeing to stop
production by 1996. This goal had already been prescribed in
the US in 1990 by the amendments of the Clean Air Act. In
1994, Europe decided that a phase-out could be achieved in
Europe by 1995
Greenhouse Gas
Years in the Warming
Atmosphere Potential
CO2=1
Sources
Carbon Dioxide
(CO2)
100
1
Burning Oil, coal, plants, deforestation,
cellular respiration
Carbon
Tetrachloride (CCl4)
45
1500
Cleaning Solvent
CFC
15 (100 in
Strat)
1000-8000
AC, Refrigerators, foam products, insulation
Halons
65
6000
Fire Extinguishers
HCHCs
10-400
500-2000
AC, Refrigerators, foam products, insulation
HFCs
15-400
150-13000
AC, Refrigerators, foam products, insulation
Methane (CH4)
15
25
Rice cultivation, production of coal, natural
gas leaks
Nitrous Oxide (N2O) 115
300
Burning fossil fuels, fertilizers, livestock
wastes, plastic manufacturing
Sulfur Hexafluoride
(SF6)
3,200
24000
Electrical industry as a replacement for
PCBs
Troposphereic
Variable
3000
Combustion of fossil fuels
Human Sources of Greenhouse Gases
Greenhouse Gases
• Levels of greenhouse gases have increased by
25% since the industrial revolution
• During the last 20 years, ¾ of all human-made
CO2 was from burning fossil fuels
• Energy related green house gases represent
82% of the US anthropogenic emissions
• Although the carbon cycle takes up 6.1 billion
metric tons of anthropogenic CO2 emissions,
3.2 billion metric tons are still added annually
Impacts and Consequences of Global
Warming
• Acidification: The ocean can absorb CO2 but
increased CO2 levels in the ocean lower the
pH of the water causing it to be more acidic.
This adversely affects corals, plankton, and
reproduction rates
• Forest fires: Boreal forest fires in N America
used to average 2.5 million acres but now
average about 7 million acres. This may also
be because of forest management practices
Impacts and Consequences of Global
Warming
• Air temps average 5-9 F warmer than they were before the
Industrial Revolution
• Historic increases in temp average less than 2 F per 1,000
years
• Higher temps will result in higher amounts of rain due to
higher rates of evaporation
• Hurricanes of category 4/5 have risen from 20% in the 70s to
35% in the 90s
• Precipitation due to hurricanes is up 7% in the US
• More rainfall increases erosion which then leads to higher
rates of desertification due to deforestation… this leads to
loss in biodiversity from loss in habitats
• El Nino and La Nina Patterns and their frequencies have also
changed
Impacts and Consequences of Global
Warming
Impacts and Consequences of Global
Warming
• Displacement of People: The UN estimates that
bt 2050, 150 million people will need to relocate
worldwide. This is because of effects of coastal
flooding, shoreline erosion and agricultural
disruption
• Increases Health and Behavioral Effects: Higher
temps result in a higher rate of heat-related
deaths. Estimates indicate that a temp increase of
just 2F will result in about 25,000 additional
homicides in the US due to stress and resulting
rage.
Impacts and Consequences of Global
Warming
• Ecological Productivity: Satellite photos have
shown that productivity in the N hemisphere has
increased since 1982, BUT, biomass increases due
to warmer temps reaches a certain point- the
point where limiting factors of water and
nutrients curb future productivity increases. In
the tropics, plants increase productivity more so
than trees (which are carbon sinks). With higher
% of plants due to increase temps and CO2
concentrations, the rates of decomposition
increase because the plants are shorter lived. As
a results, more carbon enters the carbon cycle.
Impacts and Consequences of Global
Warming
• Glacier Melting: Total surface area of glaciers worldwide has
decreased 50% since the end of the 19th century. Temps in the
Antarctic Southern Ocean rose 0.31 F between the 50s-80s.
Glacier melting causes: landslides, flash floods, lake overflow
and increased variation in water flows into ricers
• Hindu Kush and Himalayan glacier melts are reliable water
sources for many people in China, India and much of Asia.
• Global warming initially increases water flow causing flooding
and disease. Flow will then decrease as the glacier volume
dwindles, resulting in drought.
• Eventual decreases in glacial melt will also affect hydroelectric
productions
Impacts and Consequences of Global
Warming
• Increase in Disease: Rates of Malaria, cholera and
other waterborne diseases will increase.
Remediation and mitigation efforts will end up
costing more
• Increased Property Loss: Weather-related
disasters have increased 3-fold since the 60s.
Insurance payouts have increased 15-fold
(adjusted for inflation) during the same time
period. Much of this can be attributed to people
moving to vulnerable coastal areas.
Impacts and Consequences of Global
Warming
• Increase in Economic Development: Money that
was designed to increase education, improve
health care, reduce hunger and improve
sanitation and fresh water supply will now go to
mitigating the effects of climate change
• Releases of Methane from Hydrates in Coastal
Sediments: Methane hydrate is a form of water
ice that contains methane within its crystal
structures. Extremely large deposits of this
resource have been discovered in ocean
sediments.
Impacts and Consequences of Global
Warming
• Loss of Biodiversity: Arctic fauna will be most affected.
The food webs of polar bears that depend on ice flows,
birds and marine mammals will be negatively
impacted. Many refugee species have shifted their
ranges toward the poles, averaging 4 miles per decade.
Bird migrations are averaging over two days earlier per
decade. Grasses have become established in Antarctica
for the first time. Many species of dish and krill that
require cooler waters will be negatively impacted.
Decreased glacier melt will impact migratory fish, such
as salmon, that need sufficient river flow
Impacts and Consequences of Global
Warming
• Releases of Methane from Thawing
Permafrost: would increase bacterial levels in
the soil and eventually lead to higher releases
of methane. Estimates of melting of
permafrost peat bogs in Siberia could release
as much as 70,000 million metric tons of
methane in the next few decades
• POSITIVE FEED BACK LOOP
Impacts and Consequences of Global
Warming
• Rise in Sea Level: sea levels have risen 400 feet since the peak of
the last ice age. From 3,000 years ago to the start of the industrial
revolution, a rate of sea level rise averaged 0.1-0.2 mm per year.
Since 1900, sea level has risen about 3 mm per year (over a 10-fold
increase). As increase in global temperatures of 3F-8F is estimated
to lead to an increase of 6-37 inched in seal level rise. If all the
glaciers, ice caps and ice sheets melted on earth the sea level
would rise 225 ft.
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–
–
–
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Increase coastal erosion
Create higher storm surge flooding
Increase loss of property and coastal habitats
Cause losses in fish and shellfish catches
Cause loss of cultural resources and values such as tourism and
recreation
– Cause losses in agriculture and aquaculture due to diminishing soil and
water quality
– Result in the intrusion of salt water into aquifers.
Impacts and Consequences of Global
Warming
• Slowing or Shutdown of Thermohaline
circulation: Melting of the glaciers in Greenland
would shift the salt water- freshwater balance of
the North Atlantic. This would result in a
decrease of heavier saline waters sinking than in
traditional ocean circulation patterns. This would
have significant effects on the fishing industry.
Localized cooling in the N Atlantic brought about
through the reduction of thermohaline
circulation currents would result in much colder
temps in Great Britain and Scandinavia
Reducing Climate Change
• World carbon dioxide levels are expected to increase by 2%
annually between 2001-2025.
• Much of the increase in these emissions is expected to
occur in the developing world (China and India) where
emerging economies fuel economic development with
fossil energy.
• Developing countries emissions are expected to grow by 3%
annually between 2001-2025 and will surpass emissions of
industrialized countries by 2019 .
• The US produces about 25% of global CO2 emissions by
burning fossil fuels.
• This is due to a robust economy and 85% of the US’s energy
needs are met through burning fossil fuels.
Reducing Climate Change
• To stabilize the current global warming crisis
would require:
– A decrease in methane emissions by 8%
– A decrease in Nitrous Oxide emissions by 50%
– A decrease in carbon dioxide emissions by up to
80%
Reducing Climate change
1. Increasing the efficiency of cars, this would decrease
dependence on oil and other fossil fuels. Cars currently
represent 25% of the CO2 emissions in the US
2. Use more energy efficient sources or move to renewable
energy.
3. Finding chemical substitutes that don’t impact global
warming and banning ones that do
4. Slow down the rate of deforestation and increase
reforestation
5. Reduce dependence on inorganic, nitrogen-based fertilizers
and substituting conservation tillage techniques
6. Support treaties, protocols and legislation that require a
reduction in greenhouse gases