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