Climate Change. Chapter 16

Transcription

1 + Climate Change Chapter 16

2 + Section 16.1 Our Dynamic Climate

3 + 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.

4 + Greenhouse Effect Gasses n Main Gasses: n Water (H 2 O) n Carbon Dioxide (CO 2 ) n Methane (CH 4 ) n Others Gasses: n CFCs (in aerosol cans) n Nitrous Oxides (NO) n Ozone (O 3 ) n We enhance GHE by increasing amount of gasses

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6 + 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.

7 + 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.

8 + 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 CO 2 than is found in the atmosphere.

9 + 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. Mount St. Helens Did You Know? Ice ages are at least partially caused by changes in Earth s orbit and axis.

10 + 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.

11 + Let s Review!

12 + Section 16.2 Climate Change

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14 + 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

15 + 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

16 + Snow Data

17 + Ice Data

18 + Ice Cover: 1979 vs

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20 + 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 CO 2 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

21 + 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

22 + 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 CO 2 when burnt, often sulfur too Smog and lung disease Degrades land after mining Less energy per unit mass than other fossil fuels

23 + 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 CO 2 Emissions

24 + 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

25 + Section 16.3 Effects of Climate Change

26 + 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 Did You Know? Robins arrive on a Colorado mountaintop about 2 weeks earlier than they did in n Migrations start earlier in the spring.

27 + 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 CO 2 n Affects shell formation The color of healthy brain coral comes from algae. When the algae die, coral bleaching occurs.

28 + 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

29 + 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. Black-legged ticks, known to spread Lyme disease Did You Know? In the United States, 53% of the population lives in coastal areas.

30 + Section 16.4 Responding to Climate Change

31 + 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.

32 + World Energy Sources

33 + 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

34 + R&D Spending as a Share of Sales

35 + 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

36 + 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

37 + 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

38 + 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?

39 + 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

40 + 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

41 + 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.

42 + 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.

43 + Strategies for Reducing Greenhouse Gases n Agriculture / forestry: Reduce soil erosion and replace cut trees, to curb CO 2 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 CO 2 emissions.

44 + 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