Climate Change

Chapter 19

An Enormous Cloud of Air Pollutants and Ash from Mt. Pinatubo

June 1991: Mount Pinatubo (Philippines) exploded

Airborne pollutants, deaths, and damage

Affected climate temperature James Hansen(NASA) cooled the

temp of the earth by )0.5* over a 19th month period. Then the earth would warm

Earth’s Future Temperature and Climate Change

• The overwhelming scientific consensus is that the earth’s atmosphere is warming rapidly, mostly because of human activities, and that this will lead to significant climate change during this century.

Global Warming and Global Cooling Are Not New

• Over the past 4.7 billion years the climate has been altered by• Volcanic emissions• Changes in solar input• Movement of the continents• Impacts by meteors

• Over the past 900,000 years• Glacial and interglacial periods

Global Warming and Global Cooling Are Not New

Over the past 10,000 years◦Interglacial period, fairly stable climate and steady

average global surface temperatureOver the past 1,000 years

◦Temperature stable but began to rise during the last century when forests cleared, fossil fuel burned

Over the past 100 years◦Temperature changes mostly since 1975

Different techniques…….. Analysis of radioisotopes in rocks and fossils Plankton and radioisotopes in ocean sediments Tiny bubbles of ancient air found in ice cores from glaciers Temperature measurements taken at different depths from bore holes

drilled deep into the earth’s surface Pollen from lake/bog bottoms Tree rings Historical records - 1861

Estimated Changes in the Average Global Temperature of the Atmosphere

Our Climate, Lives, Economies Depend on the Natural Greenhouse Effect ( Arrhenius)

• Without the natural greenhouse effect, warms the earth’s lower atmosphere and surface.

• Solar energy absorbed by the earth radiates into the atmosphere as infrared radiation(heat)

• 1% of earth’s lower atmosphere is compressed of greenhouse gases- water vapor, carbon dioxide, methane, and nitrous oxide• Cold, uninhabitable earth

Human Activities Emit Large Quantities of Greenhouses Gases

• Since the Industrial Revolution (275 years ago)• CO2, CH4, and N2O emissions higher• Main sources: agriculture, deforestation, and burning of

fossil fuels

• Correlation of rising CO2 and CH4 with rising global temperatures, during past 400,000 years

• Countries with the largest CO2 emissions- US, China, EU-27 contries, Indonesia, Russia, Japan, India

Human Activities Emit Large Quantities of Greenhouses Gases

Per capita emissions of CO2

Scientific and economic studies◦ 2007: Field and Marland

560 ppm by 2050 – 1390 by 2100Tipping point 450 ppm

◦ 2008: Aufhammer and Carson China’s CO2 emission growth may be underestimated

Ice core analysis – 60% of methane emissions ◦ human impact – landfills, raising live stock, extracting fossil fuels

◦Nitrous oxide – nitrogen fertilizers

Atmospheric Levels of CO2 and CH4, Global Temperatures, and Sea Levels

The Atmosphere Is Warming Mostly Because of Human Activities

• Intergovernmental Panel on Climate Change (IPCC)• 90–99% likely that lower atmosphere is warming• 1906–2005: Ave. temp increased about 0.74˚C• 1970–2005: Annual greenhouse emissions up 70%• Past 50 years: Arctic temp rising almost twice as fast as the rest of the earth• Melting of glaciers and floating sea ice• Prolonged droughts: increasing• Last 100 years: sea levels rose 10–20 cm

Alaska’s Muir Glacier

• Al Gore and the IPCC : Nobel Peace Prize

• Natural and human-influenced factors could have an effect on temperature changes

The Big Melt: Some of the Floating Sea Ice in the Arctic Sea

Drop in average cover of summer arctic ice

Scientific Consensus about Future Temperature Change?

• Mathematical models used for predictions

• Global warming: rapid rate

• Human factors are the major cause of temperature rise since 1950

• Human factors will become a greater risk factor

Model of Some Major Processes That Interact to Determine Climate

Comparison of Measured Temperature from 1860–2007 and Projected Changes

Is a Hotter Sun the Culprit?

• Since 1975- satellite and balloon measurements • Troposphere has warmed• Stratosphere has cooled

• Scientists have concluded that the rapid rise in global mean temperature could not be the result of increased solar output

Can the Oceans Save Us?• Solubility of CO2 in ocean water – removes 25-30% of the carbon dioxide

pumped into the lower atmosphere by human activities. Some of it converted to insoluble carbonate salts that are buried in the bottom sediments

• Warmer oceans • Solubility decreases increases atmospheric CO2

• Coral reefs destroyed• Increased acidity –less carbon dioxide absorbed, increases growth

of some algae• drop in populations of phytoplankton,

• Antarctica’s Southern Ocean and the North Atlantic Ocean –decrease in carbon dioxide uptake

There Is Uncertainty about the Effects of Cloud Cover on Global Warming

• Warmer temperatures create more clouds by increased evaporation of surface water

• Thick, light-colored low altitude clouds: decrease surface temperature• Thin, cirrus clouds at high altitudes: increase surface temperature

• Effect of jet contrails on climate temperature – they expand and turn into cirrus clouds that release heat into the upper troposphere

Outdoor Air Pollution Can Temporarily Slow Global Warming

• Aerosol and soot pollutants• light colored sulfate particles, reflect sunlight and

cool atmosphere• sulfate particles also cool the lower atmosphere by

forming condensation nuclei that form cooling clouds

Some Possible Effects of a Warmer Atmosphere……………

• The projected rapid change in the atmosphere's temperature during this century is very likely to

• Increase drought and flooding, • shift areas where food can be grown, • raise sea levels, • result in intense heat waves,• cause the premature extinction of many species.

Enhanced Global Warming Could Have Severe Consequences• Very rapid, global change in climate – projected rapid increase in average

temperature in the lower atmosphere

• Worst-case scenarios• Ecosystems collapsing• Low-lying cities flooded• Wildfires in forests• Prolonged droughts: grasslands become dust bowls• More destructive storms• Glaciers shrinking; rivers drying up

Fig. 19-7, p. 507

Stepped Art

Severe Drought Is Increasing from 15-30%

• less moisture in the soil – NPP will decrease• stream flows and available water will decline• Biodiversity will decrease• growth of plants/trees will slow• forest and grassland fires will increase• some lakes/seas will shrink and disappear, rivers will fail

to reach the sea• 1-3 billion people will face water shortage• dry climate biomes will increase – savannas,

chapparal,deserts

Ice and Snow Are Melting • global warming be worse in the polar regions – exposure

of darker land, absorb more solar radiation• floating sea ice disappearing – could affect the average

rate of precipitation in certain areas

• Mountain glaciers affected by• Average snowfall, adds to mass in winter• Average warm temperatures- apur their melting during

the summer

Ice and Snow Are Melting

• Europe’s Alps• Glaciers are

disappearing• South America

• Glaciers are disappearing

• Greenland• Warmer

temperatures

Areas of Glacial Ice Melting in Greenland

Melting Ice in Greenland

• Largest island: 80% composed of glaciers

• 10% of the world’s fresh water

• 1996–2007: net loss of ice doubled

• Effect on sea level if melting continues

Sea Levels Are Rising – 90-99% certainity• Expansion of warm water and

melting of land based ice–• Water will rise 18-59 cm (0.6-1.9

feet) during this century• storm surges of 6 meters (20 feet)• accompanying tropical cyclones

and tsunamis

Sea Levels Rising • Degradation and loss of 1/3 of coastal estuaries, wetlands, and coral reefs

• Disruption of coastal fisheries• Flooding of

• Low-lying barrier islands and coastal areas• Agricultural lowlands and deltas

• Contamination of freshwater aquifers• Submergence of low-lying islands in the

Pacific and Indian Oceans and the Caribbean

Maldives- Indian Ocean

Projected Decline in Arctic Tundra in Portions of Russia from 2004 - 2100

Melting of permafrost in tundra soils releases methane and carbon di oxide

Loss of arctic tundra-reduce grazing lands for caribouBoreal vegetation would replace tundra

Ocean Currents Are Changing but the Threat Is Unknown

• Melting glaciers, particularly in Greenland• Increased rain in the North Atlantic• Could add enough fresh water to disrupt the flow of deep and shallow ocean

currents• Could climate of Northern Europe. N. America and Japan

• Not thought to be an immediate problem on the ocean currents

Extreme Weather Will Increase in Some Areas

• Heat waves and droughts in some areas- kill people, reduce crop production, expand deserts

• Prolonged rains and flooding(flash floods) from heavy and prolonged precipitation

• Will storms get worse? • More studies needed – Saunders and Lea (2008)

• Hurricanes Katrina and Rita – lost 320 million big trees

Global Warming Is a Major Threat to Biodiversity

• Most susceptible ecosystems• Coral reefs• Polar seas• Coastal wetland• High-elevation mountaintops• Alpine and arctic tundra

Changes in water temperature, relative to coral bleaching threshold

Global Warming Is a Major Threat to Biodiversity

• 30% of land –based plants and animals will disappear (temp change 1.5-2.5*C)

• What about• Migratory animals• Forests

• Some organisms will increase• Insects, Fungi, Microbes

Exploding populations of mountain pine beetles

Destroy lodge pole pine forests

Climate Change Will Shift Areas Where Crops Can Be Grown

• Regions of farming may shift• Decrease in tropical and subtropical areas• Increase in northern latitudes• Overall food productivity would decrease because of less productivity soil• Decrease in food production in farm regions dependent on rivers fed by snow

melt

• Genetically engineered crops more tolerant to drought

Climate Change Will Threaten the Health of Many People

• Deaths from heat waves will increase

• Deaths from cold weather will decrease

• Higher temperatures can cause• Increased flooding• Increase in some forms of air pollution, more O3

• More insects, microbes, toxic molds, and fungi

Norman Myers – 150 to 200 million environmental refugees in this century

What Can We Do to Slow Climate Change……………..

• To slow the rate of global warming and climate change, we can• increase energy efficiency, • sharply reduce greenhouse gas emissions,• rely more on renewable energy resources• slow population growth.

What Can We Do to Slow Climate Change?

• Governments can • subsidize energy efficiency and renewable energy use, • tax greenhouse gas emissions, • set up cap-and-trade emission reduction systems, • help to slow population growth.

Dealing with Climate Change Is Difficult Global problem

Long-lasting effects

Long-term political problem

Harmful and beneficial impacts of climate change unevenly spread

Many proposed actions disrupt economies and lifestyles

What Are Our Options?

• Two approaches• Drastically reduce the amount of greenhouse gas emissions• Recognize that some warming is unavoidable and devise strategies to reduce

the harmful effects of global warming

• Will we reach a political tipping point before we reach irreversible climate change tipping points?

We Can Reduce the Threat of Climate Change

• Input or prevention strategies• Improve energy efficiency to reduce fossil fuel use• Shift from non-renewable carbon-based fossil fuels to a mix of carbon-free

renewable energy resources• Stop cutting down tropical forests

• Output strategy• Capture and store CO2 -

Avoiding Catastrophe: We Can Reduce the Threat of Climate Change

• Socolow and Pacala• Climate stabilization wedges • Keep CO2 emissions to 2007 levels by 2057

• Brown: need to do more• Cut CO2 emissions by 80% by 2020

• 2008 book: Plan B 3.0: Mobilizing to Save Civilization

We Can Reduce the Threat of Climate Change

• Output solutions• Massive global tree planting – 4 billion need to be planted

• Wangari Maathai• Great Wall of Trees: China and Africa

• Plant fast-growing perennials such as switch grass on degraded land which takes carbon dioxide from the air and stores it in the soil. Can be used to produce ethanol

Fig. 19-13, p. 515

SOLUTIONS

Global Warming

Prevention CleanupCut fossil fuel use (especially coal)

Remove CO2 from smokestack and vehicle emissionsShift from coal to natural gas Store (sequester) CO2 by planting treesImprove energy efficiencySequester CO2 deep underground (with no leaks allowed)

Shift to renewable energy resources

Transfer energy efficiency and renewable energy technologies to developing countries

Sequester CO2 in soil by using no-till cultivation and taking cropland out of production

Reduce deforestation Sequester CO2 in the deep ocean (with no leaks allowed)

Use more sustainable agriculture and forestry

Repair leaky natural gas pipelines and facilitiesLimit urban sprawl

Reduce poverty Use animal feeds that reduce CH4 emissions from cows (belching)

Slow population growth

Fifteen Ways to Cut CO2 Emissions

Fig. 19-14, p. 515

Stepped Art

Fig. 19-15, p. 516

Oil rigTanker delivers CO2 from plant to rig

Coal power plant

Tree plantation

CO2 is pumped down from rig for disposal in deep ocean or under seafloor sediments

Abandoned oil field

Switchgrass Crop field

CO2 is pumped

underground

Spent oil or natural gas reservoir

Spent coal bed cavern

Deep, saltwater-filled cavern

= CO2 pumping

= CO2 deposit

Some Output Methods for Removing CO2 from the Atmosphere and storing it

Is Capturing and Storing CO2 the Answer?

• Carbon capture and storage (CCS) – involves removing carbon dioxide from the smoke stacks of coal- burning power and industrial plants and storing them somewhere

• Several problems with this approach• Power plants using CCS

• More expensive to build• None exist

• Unproven technology• Large inputs of energy to work• promotes continued use of coal• Effect of government subsidies and tax breaks• Stored CO2 would have to remain sealed forever: no leaking

Use Geo-Engineering Schemes to Help Slow Climate Change……..

• CCS – large scale geo engineering scheme opposed by scientists because long term effects on earth’s energy flow, chemical cycling processes and vital biodiversity are unknown

• Injection of sulfate particles into the stratosphere by balloons, large jet planes, giant cannons

• Huge amounts of sulfur dioxide injected into the atmosphere every 2 years• Would it have a cooling effect?• Would it accelerate O3 depletion?

Use Geo-Engineering Schemes to Help Slow Climate Change……

• Remove HCl from seawater – reduce ocean acidity. How would it affect the ecology ?

• Pump up nutrient-rich deep ocean water and cause algal blooms, remove carbon dioxide and emit dimethyl sulfide which will contribute to the formation of low clouds that would reflect sunlight

• Re-ice the Arctic – 8,000 ice making barges• Wrap large areas of the glaciers with insulating blankets

Cost to Slow Climate Change….

• Short-term costs lower

• Local and global economies may be boosted

• Provide jobs because of new technology associated with alternative energy

• Less expenses for remediation

Governments Can Help Reduce the Threat of Climate Change

• Strictly regulate CO2 and CH4 as pollutants• Cap-and-trade approach-political advantage• carbon taxes - levy energy taxes on each unit of fossil fuel that is burned – tax

pollution, not payrolls• Increase subsidies to encourage use of energy-efficient technology• Technology transfer-fund the transfer of green technologies to phase out

older, energy wasting technologies

Governments Can Enter into International Climate Negotiations: The Kyoto Protocol

• 1997: Treaty to slow climate change -2200 delegates from161 nations• 1st phase – 174 of the world’s 194 countries (but not US) ratifying the

agreement by mid -2008.• The Kyoto Protocol

• Reduce emissions of CO2, CH4, and N2O by 2012 to levels of 1990• Trading greenhouse gas emissions among countries• Not signed by theUS.(2001) 67% of ppublic upset

• President G.W. Bush’s reasons-would harm US economyCap and Trade systems need to have the caps set low to increase value of the tradable allowances

Move Beyond the Kyoto Protocol

2004: Stewart and Wiener◦ New treaty needed

Should be led by the U.S.

Include China, India, Brazil and other developing countries that are getting industrialized and will be soon emitting the more than 50% of the world’s greenhouse gases

Cap-and-trade emissions program

Set up achievable 10 year goals – to reduce greenhouse gases over the next 40 years

Governments Are Leading the Way are……• Costa Rica: goal to be carbon neutral by 2030 – 78% from hydroelectric,18%

from wind and geothermal• Norway: aims to be carbon neutral by 2050• China and India must change energy habits• U.S. cities and states (27+ DC: solar and wind) taking initiatives to reduce

carbon emissions• 650 cities around the world, including 453 US cities reduce greenhouse gases • Portland, Oregon – 1993-2005 greenhouse gases at 1990 levels

Reducing Greenhouse Gas Emissions in California (12th largest producer of greenhouse gases)

• Use of energy-efficient appliances and buildings• Incentives for consumers to use less energyHas saved California from building 24 new power plants

• California sued the EPA so that they and 17 other states can set tougher emission standards

Some Companies and Schools Are Reducing Their Carbon Footprints

• Major global companies reducing greenhouse gas emissions- reduce 10-65% below 1990 levels by 2010

• Alcoa• DuPont• IBM• Toyota• GE• Wal-Mart $12 million /year saved by using LED’s

• Fluorescent light bulbs• Auxiliary power units on truck fleets – no idling• Carbon Disclosure Project

Some Companies and Schools Are Reducing Their Carbon Footprints

• Colleges and universities reducing greenhouse gas emissions• Oberlin College, Ohio, U.S.• 25 Colleges in Pennsylvania, U.S.• Yale University, CT, U.S.

• Largest teach-In Feb 2008-1500 colleges, climate change and sustainability

What Can You Do? Reducing CO2 Emissions

Prepare for the Harmful Effects of Climate Change

• Reduce greenhouse gas emissions as much as possible (50-85% cut in by 2050) to prevent the planet from heating up by 2*C

• Move people from low-lying coastal areas

• Limit coastal building

• Remove hazardous material storage tanks away from the coast

Prepare for the Harmful Effects of Climate Change

• Genetically engineer crops more tolerant to drought

• Stockpile 1–5 years of key foods

• Waste less water

• Connect wildlife reserves with corridors

Fig. 19-17, p. 522

Develop crops that need less water

Waste less water

Connect wildlife reserves with corridors Move people away

from low-lying coastal areas

Move hazardous material storage tanks away from coast

Stockpile 1- to 5-year supply of key foods

Prohibit new construction on low-lying coastal areas or build houses on stilts

Expand existing wildlife reserves toward poles

Which do you think is the most important ?