Section 16.1 Climate Change Our Dynamic Climate · PDF file1 + Climate Change Chapter 16 +...
Transcript of Section 16.1 Climate Change Our Dynamic Climate · PDF file1 + Climate Change Chapter 16 +...
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Climate Change
Chapter 16
+Section 16.1 Our Dynamic Climate
+The Greenhouse Effect
n A natural process in which greenhouse gases absorb heat and release it slowly back into the atmosphere
n Greenhouse effect is good!
n We would freeze without it!
Did You Know? Greenhouse gases absorb heat and release it slowly, while an actual greenhouse traps warm air inside a structure.
+Greenhouse Effect Gasses
n Main Gasses: n Water (H2O) n Carbon Dioxide (CO2) n Methane (CH4)
n Others Gasses: n CFCs (in aerosol cans) n Nitrous Oxides (NO) n Ozone (O3)
n We enhance GHE by increasing amount of gasses
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+The Effect of Latitude
• Latitude is a measure of a place’s distance from the equator.
• Horizontal Lines
• Cold at poles
• Warm at equator
• The seasons are caused by the changing angles at which sunlight strikes Earth.
+Wind
n Caused by convection currents
n Rising warm air
n Falling cool air
n Transports moisture and heat
n Warm air moves away from equator, toward poles.
n Cold air moves from poles toward equator.
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The Oceans and Climate
n Ocean currents caused by:
n unequal heating of water
n unequal salinity
n Currents affect climate by transporting heat.
n El Niño and La Niña:
n disruptions to normal climate patterns
n caused by variations in interactions between ocean and atmosphere.
Did You Know? The ocean absorbs a lot of carbon dioxide, causing a global cooling effect. The ocean can hold 50 times more CO2 than is found in the atmosphere.
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+Other Factors That Affect Climate
• Topography:
• Higher altitudes have cooler temps
• Mountain ranges affect rainfall
• Volcanoes:
• Ash clouds can temporarily block sunlight
• Causes air to cool
• Vegetation:
• Plant life promotes cloud formation
• Absorbs carbon dioxide. Did You Know? Ice ages are at least partially caused by changes in Earth’s orbit and axis.
Mount St. Helens
+Climate Change
n All of these factors cause climate to fluctuate (go up and down) over time.
n But what we are seeing now is MUCH greater than normal.
+Let’s Review!
+Section 16.2 Climate Change
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+Studying Climate Change
n Direct measurement is used to study today’s climate.
n Proxy indicators, such as patterns in tree rings, give clues about past climates.
n Models are used to make predictions about future climates.
Cross-section of a tree trunk
+Evidence of a Warming Earth
n Rising global surface temperatures
n Changes in precipitation patterns
n Melting ice (glaciers, polar ice)
n Rising sea level
Did You Know? Since 1986, the Larsen Ice Shelf near Antarctica has lost an area more than 3 times the size of Rhode Island.
Both photos show Sperry Glacier in Montana’s Glacier National Park. Top: 1913: Bottom: 2008
+Snow Data
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+Ice Data
+Ice Cover: 1979 vs. 2003
2003 1979
+IPCC 2007 Report n GHG é from pre-industrial levels
n Air and sea temps é
n Ice and snow ê
n Sea level é n Hurricane intensity é
n Predictions: n CO2 levels doubling will cause 3 degree temp é n Dry regions dryer, wet regions more wet n Coastal erosion é n Coral bleaching é n Ecosystem degradation = carbon sinks ê
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+Cause of Climate Change
n Increases in greenhouse gases are the primary cause of climate change.
n The increase in greenhouse gases is mainly due to: n Burning of fossil fuels n Coal n Oil n Natural Gas
n Changes in land use
+Coal (Fossil Fuel) n Pictures of Coal Today
n Fossilized plants from millions of years ago
n Seams of coal in strata between rock
n Burnt to provide heat or produce electricity
• Advantages: • High supply • Easy to transport • No processing needed • Cheap
• Disadvantages: • Non-renewable • Releases CO2 when burnt,
often sulfur too • Smog and lung disease • Degrades land after mining • Less energy per unit mass
than other fossil fuels
+Oil (Fossil Fuel)
n Liquid found in porous rocks
n Extracted by oil wells, some under ocean
n Advantages: n High heat n Many uses n Cheap to mine
n Disadvantages: n Limited supply n Oil spills n CO2 Emissions
+Natural Gas (Fossil Fuel) n Methane and other hydrocarbons trapped
between seems of rock
n Extracted by drilling: Fracking
n Used directly in homes
n Advantages: n Clean n Cheap n High heat released
n Disadvantages: n Limited supply n Emissions
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+Section 16.3 Effects of Climate Change
+Effects on Ecosystems
n Locations of biomes could shift
n Animals will shift territories n Some animal populations staying
high throughout winter
n Plants will begin to germinate in different latitudes n May not be fast enough to prevent extinction n Plants are blooming earlier
n All polar species may go extinct
n Migrations start earlier in the spring.
Did You Know? Robins arrive on a Colorado mountaintop about 2 weeks earlier than they did in 1970.
+Effects of a Changing Ocean
n Increase in ocean temperature à coral bleaching
n Algae living within corals die.
n Without the algae, coral dies
n Changes in ocean acidity
n Caused by increase in dissolved CO2
n Affects shell formation
The color of healthy brain coral comes from algae. When the algae die, coral bleaching occurs.
+Effects on Us
n Rivers and lakes may dry up
n Water supply also reduced by melting glaciers
n Increased heat waves and disease
n Environmental refugees
n Countries could gain or lose resources à GDP n Easier to mine and navigate in north
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+Future Effects of Climate Change
n Diseases: Warmer temperatures can promote spread of diseases transmitted from animals to people.
n Sea level: Low-lying populated coastal areas may flood as sea levels rise.
n Water supply: Saltwater contamination of aquifers resulting from rising sea levels and a decrease in glacial ice may threaten freshwater supplies.
Did You Know? In the United States, 53% of the population lives in coastal areas.
Black-legged ticks, known to spread Lyme disease
+Section 16.4
Responding to Climate Change
+Use and Production of Electricity
n Carbon footprint: The amount of carbon dioxide for which an individual or group is responsible
n Most electricity is generated by burning fossil fuels.
n Reducing electricity use reduces carbon footprints.
n Ways to reduce electricity use: n Use energy-efficient technologies, which
lessen the electricity needed to do a job. n Reduce the use of electrical devices and
appliances.
+World Energy Sources
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+How much longer for fossil fuels?
n Common Estimates of Fossil Fuel Supplies: n Oil à 50 years (2/3 in Middle East) n Natural Gas à 70 years n Coal à 250 years
n Depends on rate of use, other tech, how efficient we are at using and extracting more.
n But we WILL run out. (non-renewable)
n As we develop we use more fuel n If less developed countries use oil at the per
capita rate at we do, we will run out in 17 years or less
n We have the most coal left but it’s the dirtiest
+ R&D Spending as a Share of Sales
+Alternate Sources of Electricity
n Alternative Sources of Electricity
n Nuclear power
n Solar power
n Wind power
n Hydroelectric power
n Geothermal power
Wind turbines
+Nuclear n Uranium mined n Atoms split n 80 years worth left n Could get more from ocean
n Advantages: n Cheap once reactor is built n Huge release of energy n No pollutants unless accident
n Disadvantages: n Nuclear waste n Risk of nuclear weapons
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+Solar
n Solar panels (Solar-photovoltaic Cells) n Converting sun to energy via chemical energy
n Advantages: n Infinite supply n Safe n High energy output n On your own house
n Disadvantages: n Expensive (May change soon) n Doesn’t work in the dark
+Wind n Wind turbines n Usually on wind farm
n Advantages: n Clean
n Little Maintenance
n Disadvantages: n Need wind
n Windy sites often not near population
n Expensive
n Noise pollution
n Disruptive to birds?
n Ugly?
+Hydroelectric Power
n Get energy from movement of water
n Water powers turbines which generate electricity
n Advantages: n Lots of energy
n Water reserves
n Good safety
n Disadvantages: n Expensive to build
n Flood Risk
n Eco impact of dams
+Geothermal n Cold water pumped into the earth
n Comes out as steam n Used as heat n Power turbines
n Advantages: n Infinite supply
n Currently being used successfully
n Disadvantages: n Expensive to set up
n Only works where there is volcanic activity and therefore high heat in the earth
n Underground gasses must be disposed of properly
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+Advances in Vehicle Technology
n Transportation is the second largest source of greenhouse gas emissions in the United States, second only to electricity.
n Alternatives to fuel-only cars include:
n Electric vehicles
n Gasoline-electric hybrid vehicles
n Alternative fuels such as compressed natural gas
n Vehicles that use hydrogen fuel cells.
+Reducing Dependence on Cars
n Biking, walking, and using public transportation are all ways to reduce fossil fuel use.
n Many communities lack good public transportation.
Did You Know? The average American family makes 10 trips by car each day.
+Strategies for Reducing Greenhouse Gases n Agriculture / forestry: Reduce soil erosion
and replace cut trees, to curb CO2 emissions
n Cap-and-Trade: System of emission allowances that can be sold or traded, gives companies incentive to reduce emissions
n Carbon tax: A tax per unit on emissions
n Carbon offsets: Companies can make a voluntary payment to a group that reduces greenhouse gases.
n Carbon sequestration: Technology is used to trap and store CO2 emissions.
+Cooperation Among Nations
n The Kyoto Protocol is a binding international effort to reduce greenhouse gases to below 1990 levels.
n Decided 1997…ongoing
n The United States did not sign the Kyoto Protocol.
n Nations are still trying to come to a consensus on how to deal with climate change