Download Climate Change PPT - Environmental Science

I will…
…explain the causes and effects of
global warming.
Weather vs. Climate
0 Climate = long term atmospheric
conditions
0 Weather = short term and localized
atmospheric condition
0 TPS Question: If there is a snow storm,
does that mean that global warming does
not exist? Why or why not?
Earth’s Climate
0 Controlled by:
0 Atmosphere
0 Sun
0 Ocean
Earth’s Climate
0 Major factors shape the earth’s climate:
0 The sun.
0 Greenhouse effect that warms the earth’s lower troposphere and
surface because of the presence of greenhouse gases.
0 Oceans store CO2 and heat, evaporate and receive water, move
stored heat to other parts of the world.
0 Natural cooling process through water vapor in the troposphere
(heat rises).
WHAT DOES ANTHROPOGENIC
MEAN?
The Atmosphere
0 Greenhouse gases – atmospheric gases that
absorb radiated heat very effectively
0 Water Vapor
0 Ozone
0 Carbon Dioxide
0 Nitrous Oxide
0 Methane
Major Greenhouse Gases
0 The major greenhouse gases in the lower atmosphere are
water vapor, carbon dioxide, methane, and nitrous oxide.
0 These gases have always been present in the earth’s troposphere
in varying concentrations.
0 Fluctuations in these gases, plus changes in solar output are the
major factors causing the changes in tropospheric temperature
over the past 400,000 years.
Major Greenhouse
Gases
0 Increases in average concentrations of
three greenhouse gases in the
troposphere between 1860 and 2004,
mostly due to fossil fuel burning,
deforestation, and agriculture.
Figure 20-5
Fig. 20-5a, p. 467
Fig. 20-5b, p. 467
Fig. 20-5c, p. 467
The Atmosphere
0 As these greenhouse gases absorb the heat, they
warm the planets surface
THIS IS KNOWN AS THE GREENHOUSE EFFECT!
0 Some gases can warm the planet more than
others  this is known as the global warming
potential of the gas
The Atmosphere
0 Carbon dioxide is considered weaker than
methane or nitrous oxide but there is A LOT
MORE OF IT in the atmosphere
0 Therefore, it contributes more to the
greenhouse effect
0 Human activity mostly produces carbon dioxide
which makes us contributors to global warming
The Sun
0 The sun supplies Earth’s energy
0 The atmosphere, clouds, land, ice, and water
together absorb 70% of incoming solar
radiation
0 The remaining 30% is reflected back into space
0 Solar output refers to the amount of radiation
the sun emits
0 It varies during different Milankovitch Cycles
The Ocean
0 The ocean holds 50 times more carbon than the
atmosphere
0 It absorbs carbon directly from the atmosphere and
through photosynthesis of marine plants
0 PROBLEM: We are adding carbon dioxide to the
atmosphere faster than the ocean can absorb it!
PAST CLIMATE AND THE
GREENHOUSE EFFECT
Figure 20-2
Average surface temperature (°C)
Average temperature over past 900,000 years
Thousands of years ago
Fig. 20-2a, p. 465
Average surface temperature (°C)
Average temperature over past 130 years
Year
Fig. 20-2b, p. 465
Temperature change over past 22,000 years
Temperature change (C°)
Agriculture established
End of
last ice
age
Average temperature over past
10,000 years = 15°C (59°F)
Years ago
Fig. 20-2c, p. 465
Temperature change (C°)
Temperature change over past 1,000 years
Year
Fig. 20-2d, p. 465
How Do We Know What
Temperatures Were in the Past?
0 Scientists analyze tiny air
bubbles trapped in ice cores
learn about past:
0 troposphere composition.
0 temperature trends.
0 greenhouse gas
concentrations.
0 solar, snowfall, and forest
fire activity.
Figure 20-3
How Do We Know What
Temperatures Were in the Past?
0 In 2005, an ice core showed
that CO2 levels in the
troposphere are the highest
they have been in 650,000
years.
Figure 20-4
Temperature
change End of last
ice age
Thousands of years before present
Variation of temperature (C°)
from current level
Concentration of carbon dioxide
in the atmosphere (ppm)
Carbon dioxide
Fig. 20-4, p. 466
CLIMATE CHANGE AND HUMAN
ACTIVITIES
0 Evidence that the earth’s troposphere is warming, mostly
because of human actions:
0 The 20th century was the hottest century in the past 1000 years.
0 Since 1900, the earth’s average tropospheric temperature has
risen 0.6 C°.
0 Over the past 50 years, Arctic temperatures have risen almost
twice as fast as those in the rest of the world.
0 Glaciers and floating sea ice are melting and shrinking at
increasing rates.
CLIMATE CHANGE AND HUMAN
ACTIVITIES
0 Warmer temperatures in Alaska, Russia, and the Arctic are melting
permafrost releasing more CO2 and CH4 into the troposphere.
0 During the last century, the world’s sea level rose by 10-20 cm,
mostly due to runoff from melting and land-based ice and the
expansion of ocean water as temperatures rise.
Why Should We Be Concerned
about a Warmer Earth?
0 A rapid increase in the temperature of the troposphere during
this century would give us little time to deal with its harmful
effects.
0 As a prevention strategy scientists urge to cut global CO2
emissions in half over the next 50 years.
0 This could prevent changes in the earth’s climate system that
would last for tens of thousands of years.
Global Warming – Greenhouse Effect
The Scientific Consensus about
Future Climate Change
0 Measured and projected
changes in the average
temperature of the
atmosphere.
Figure 20-7
The BIG Problems
0 Burning coal creates power but releases gases that
help to drive Global Warming.
0 Arctic regions are heating up causing glaciers to melt,
dumping water in the oceans.
0 Severe weather including rainstorms, flooding,
droughts, and hurricanes are disrupting lives.
0 Wildfires caused by parched and arid conditions.
0 Droughts turn fertile land into deserts, uprooting
communities and sparking violence.
Sea Levels
0 Global sea levels have risen 4 in. to 8 in. during
the 20th century.
0 Global sea levels are anticipated to rise 19 in. to
37 in. during the 21st century if the current trend
continues.
0 If the entire Greenland
ice sheet were to melt,
the seal level would rise
an additional 23 feet.
EFFECTS OF GLOBAL WARMING
0 Between 1979 and 2005, average Arctic sea ice dropped 20%
(as shown in blue hues above).
Figure 20-8
Planet Earth – Sea Levels
www.earthobservatory.nasa.gov
Rising Sea Levels
0 During this century rising
seas levels are projected to
flood low-lying urban areas,
coastal estuaries, wetlands,
coral reefs, and barrier
islands and beaches.
Figure 20-10
Planet Earth – Sea Level Change
impact
Rising Sea Levels
0 If seas levels rise by 9-
88cm during this
century, most of the
Maldives islands and
their coral reefs will be
flooded.
Figure 20-11
Changing Ocean Currents
0 Global warming could alter ocean currents and cause both
excessive warming and severe cooling.
Figure 20-12
Carbon Dioxide Levels
0 Greenhouse gasses rose less than 1% in the 10,000
years before the Industrial Revolution.
0 Greenhouse gasses have risen 33% since the
Industrial Revolution.
0 The annual CO2 emission released by a typical 500-
megawatt coal fired
power plant is 3 million tons.
0 The U.S. has 5% of the
world’s people, yet it
produces 25% of the CO2
emission on the plant.
Carbon Dioxide Levels
EFFECTS OF GLOBAL
WARMING
0 A warmer troposphere can decrease the ability of the
ocean to remove and store CO2 by decreasing the
nutrient supply for phytoplankton and increasing the
acidity of ocean water.
0 Global warming will lead to prolonged heat waves and
droughts in some areas and prolonged heavy rains
and increased flooding in other areas.
Warming Trend
0 Earth has warmed 1.44º F during the 20th century.
0 The total temperature rise that is anticipated in the
21st century is 1.98º F to 11.52º F if current trends
continue.
0 11 out of the past 12 years
have been ranked as the
warmest in modern history
PLANET EARTH – WARMING TREND
www.greenhouse.gov.au
EFFECTS OF GLOBAL
WARMING
0 In a warmer world, agricultural productivity may
increase in some areas and decrease in others.
0 Crop and fish production in some areas could be
reduced by rising sea levels that would flood river
deltas.
0 Global warming will increase deaths from:
0 Heat and disruption of food supply.
0 Spread of tropical diseases to temperate regions.
0 Increase the number of environmental refugees.
Rain Forests
0 Slash and Burn methods
0Send clouds of gas into the atmosphere.
0Remove trees that convert CO2 into O2.
0 The source of many
prescription drugs.
0Many natural
chemicals
may never be
identified.
Deserts
0 Higher temperatures
accelerate
desertification.
0 The land becomes too
dry to support
agriculture.
0 The lives and
livelihoods of people
are threatened.
Polar Regions
0 Glaciers and ice shelves
are melting.
0 Sea levels will rise and
many land areas may be
under water.
0 Rising seas could
contaminate water
supplies with salt.
0 Warmer temperatures
could widen the range of
disease-carrying rodents
and bugs
0 Many species of wildlife
may go extinct.
Coral Reefs
0 Slight temperature changes in water can cause
coral bleaching that is devoid of life.
0 Higher temperatures
cause the polyps to
eject the algal tenants
that are living within
their tissues that
provide the color and
nutrients the coral
need to survive.
Health Risks
0 Allergies
0 Plants like ragweed and other pollen
sources will flourish under the warmer
conditions.
0 Carriers
0 Hot weather could make the global
mosquito populations (carriers of Malaria)
explode.
0 Water Sources
0 As rainfall levels increase, older cities run
a risk that overflowing sewer lines may
contaminate supplies of drinking water.
Animals
0 African Elephant – shrinking of range
and food supply
0 Wild Salmon – melting permafrost pours
mud
into rivers, burying gravel needed for
spawning
0 Prickly Pear Cactus – warming related
changes are causing disruptions in the
life cycle of plants
Animals
0 Harlequin Frog – climate changes seem to
make them more vulnerable to a deadly
fungus
0 Pinon Mouse – moving their homes to higher
elevations
0 Quiver Tree – dyeing off and moving
southward
0 Adelie Penguin, Polar Bears,
Arctic Wolves – as polar ice
melts, their habitats are endangered
More Powerful Tropical Storms
0 Over the past 35
years, the number
of hurricanes each
season has
remained
constant, but their
average intensity
has increased,
with the number of
category 4 and 5
storms (the most
powerful) nearly
doubling.
Climate Change Solutions
Review of Greenhouse Gases
Record the information about each type
of air molecule in your notebook
CO2
0 Average time in atmosphere = 100 years
0 Warming potential = 1
0 Greenhouse Gas
0 Sources:
0 Burning oil and coal
0 Cellular respiration
0 Deforestation
0 Volcanoes
0 Leads to headaches, drowsiness and fatigue
0 82% of GHG emissions
CFCs
0 Average time in atmosphere = 15 years
0 100 years in stratosphere
0 Warming potential = 1,000-8,000
0 Ozone depleting chemical
0 Sources:
0 Air conditioners
0 Refrigerators
0 Foam products
0 Insulation
0 Montreal Protocol reduced production
0 China and Brazil still produce!
CH4
0 Average time in atmosphere = 15 years
0 Warming potential = 25
0 Sources:
0 Rice cultivation
0 Coal
0 Natural gas leaks
0 Cows
0 Landfills (greatest source!)
0 Volcanoes
N2O
0 Average time in atmosphere = 115 years
0 Warming potential = 300
0 Sources:
0 Burning fossil fuels
0 Fertilizers
0 Plastic manufacturing
0 Livestock waste
0 “Laughing Gas”
0 Ozone depleting chemical
O3
0 Warming potential = 3,000
0 Good in stratosphere
0 Bad in troposphere
0 Sources:
0 Combustion of fossil fuels mixing with heat and Nox
0 Photocopiers, electrical equipment
0 Major component of smog
0 Damages human tissue, respiratory problems
SF6
0 Average time in atmosphere = 3,200 years
0 Warming potential = 24,000
0 Sources
0 Electrical industry as a replacement for PCBs (circuit
breakers, insulators, etc.)
0 Magnesium production industry
Review of Effects
0 Acidification  lower pH of sea water due to more carbon
dioxide
0 Changes in weather patterns
0 Displacement of people  relocation needed
0 Forest Fires
0 Glaciers Melting
0 Increased disease
0 Loss in economic development
0 Methane released in permafrost
0 Rise in seas level
0 Change in ocean currents
Methods to Reduce Climate
Change
1. Increase efficiency of cars
2. Move to more renewable sources of energy (wind,
3.
4.
5.
6.
solar, geothermal, etc.)
Find chemical substitutes that do not impact global
warming
Slow down the rate of deforestation and encourage
reforestation
Reduce dependence on inorganic, nitrogen-based
fertilizers and utilize soil conservation techniques
Support treaties and protocols that require
reductions in greenhouse gas emission
Take Aim at Climate Change
0 Watch this!
Answer in notebook
1. What was the purpose/goal?
2. What year did it happen?
3. Who ratified it?
4. What were some pros?
5. What were some cons?
6. Was it effective? Why or why not?
Kyoto Protocol
0 UNFCCC commits its parties by setting internationally
binding emission reduction targets (GHGs go down)
0 Developed countries are the primary target
0 Adopted in 1997 and went into effect in 2005
0 The first commitment period ended on Dec. 2012
0 Canada, US (never ratified), Japan, Russia, and New
Zealand withdrew for second round
Montreal Protocol
0 International treaty designed to phase out substances
0
0
0
0
0
responsible for ozone depletion
If adhered to, ozone will recover by 2050
Most effective international agreement to date
Most widely ratified treaty
HFCs replaced CFCs  no damage to ozone, but extremely
potent GHGs
1989
Copenhagen Accord
0 UNFCCC document
0 Not legally binding
0 Notes that climate change is a problem and promotes
the Kyoto Protocol
0 Calls for an assessment of implementation
0 Dec. 2009