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 (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 1
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 The Oceans and Climate 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. 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. 2
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. 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 3
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 Snow Data 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 4
Ice Data Ice Cover: 1979 vs. 2003 1979 2003 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 5
Cause of Climate Change Coal (Fossil Fuel) n Pictures of Coal Today 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 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 Oil (Fossil Fuel) Natural Gas (Fossil Fuel) n Liquid found in porous rocks n Extracted by oil wells, some under ocean n High heat n Many uses n Cheap to mine n Limited supply n Oil spills n CO 2 Emissions n Methane and other hydrocarbons trapped between seems of rock n Extracted by drilling: Fracking n Used directly in homes n Clean n Cheap n High heat released n Limited supply n Emissions 6
Effects on Ecosystems n Locations of biomes could shift Section 16.3 Effects of Climate Change 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 1970. n Migrations start earlier in the spring. Effects of a Changing Ocean Effects on Us 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 Rivers and lakes may dry up n Water supply also reduced by melting glaciers n Increased heat waves and disease 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. n Environmental refugees n Countries could gain or lose resources à GDP n Easier to mine and navigate in north 7
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 Section 16.4 Responding to Climate Change Did You Know? In the United States, 53% of the population lives in coastal areas. Use and Production of Electricity World Energy Sources 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. 8
How much longer for fossil fuels? R&D Spending as a Share of Sales 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 Alternate Sources of Electricity n Alternative Sources of Electricity n Nuclear power n Solar power n Wind power n Hydroelectric power Nuclear n Uranium mined n Atoms split n 80 years worth left n Could get more from ocean n Cheap once reactor is built n Huge release of energy n No pollutants unless accident n Geothermal power Wind turbines n Nuclear waste n Risk of nuclear weapons 9
Solar n Solar panels (Solar-photovoltaic Cells) n Converting sun to energy via chemical energy n Infinite supply n Safe n High energy output n On your own house n Expensive (May change soon) n Doesn t work in the dark Wind n Wind turbines n Usually on wind farm n Clean n Little Maintenance 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 Lots of energy n Water reserves n Good safety 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 Infinite supply n Currently being used successfully 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 10
Advances in Vehicle Technology Reducing Dependence on Cars 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. 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 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. 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 11