Climate Control and

Ozone DepletionChapter 19

19-1CIVILIZATION HAS EVOLVED DURING A PERIOD OF

REMARKABLE CLIMATE STABILITY, BUT THIS ERA IS DRAWING TO A CLOSE. WE ARE ENTERING A NEW ERA, A PERIOD OF RAPID AND OFTEN UNPREDICTABLE CLIMATE CHANGE. THE NEW CLIMATE NORM IS CHANGE.

LESTER R. BROWN

Global Warming and Global Cooling Are Not NewOver the past 4.5 billion years the climate has been altered by

Volcanic emissionsChanges in solar inputMovement of the continentsImpacts by meteors

Over the past 900,000 yearsGlobal Cooling and Global WarmingGlacial and interglacial (between ice ages) periods

Over the past 10,000 yearsInterglacial period-- stable climate and avg. Global surface tempAllowed agriculture and cities to flourish

Over the past 1,000 yearsTemperature stable until we clear cut forests and burn fossil fuels

Over the past 100 yearsTemperature changesmethods of determination-radioisotopes in rocks, fossils and ocean sediment, boreholes, tree rings, etc

Estimated Changes in the Average Global Temperature of the Atmosphere

Our Climate, Lives, and Economies Depend on the Natural Greenhouse Effect

Solar energy and the greenhouse effect warm the earth’s lower atmosphere and surface

Without the natural greenhouse effectCold, uninhabitable earth

1% of lower atmosphere is made of greenhouse gases (water vapor, CO2, CH4, and N2O)

1896 Arrhenius first recognized greenhouse effect

Ice Cores Are Extracted by Drilling Deep Holes in Ancient

Glaciers

Human Activities Emit Large Quantities of Greenhouses Gases

Since the Industrial Revolution (275 years ago)

CO2, CH4, and N2O emissions higherMain sources: agriculture, deforestation, and burning of fossil fuels

Correlation of rising CO2 and CH4 with rising global temperaturesCO2 has risen from 280 ppm to 384 ppm

GREENHOUSE GASES

CARBON DIOXIDEMETHANENITROUS OXIDE (N2O)CFCs WATER VAPOR

Greenhouse Gases

CO2 – most abundant greenhouse gas (GHG) Sources: burning fossil fuels, deforestation

Ice cores have shown that CO2 increasing in atmosphere – 35% higher than pre-Industrial Rev.

Natural cycling of CONatural cycling of CO22 levels levels

Seasonal shift in COSeasonal shift in CO22 production; high fall; production; high fall; low springlow spring

Ocean acts as “sink,” absorbing large amounts.

Vegetation acts as a sink (until it dies or is cut down)

Stays in the atmosphere 50- 200

Other Greenhouse GasesOther Greenhouse GasesMethane (CH4) – 21 times more

warming effect than CO2 and increasing at 8 times the rate. Atmospheric lifetime= 12 years

Methane production is faster than what is being broken down

Main sources are wetlands, rice fields, fossil fuels, livestock

Greenhouse GasesNitrous oxides – slow to breakdown Atmospheric lifetime = 120 yearsProvides 310 times more warming than CO2

Sources are fossil fuels, fertilizers, deforestation

CFCs– absorb 10,000 X more infrared than CO2

Atmospheric lifetime = 100 +Sources are foams, aerosols,

refrigerants, solvents

Water vapor – Warmed by CO2, the atmosphere is thus able to

absorb more water vapor. And that water vapor, in turn, causes further warming—it amplifies the effects of carbon dioxide.

Human ActivitiesCountries with the largest CO2 emissions

Per capita emissions of CO2

Scientific and economic studies

2007: Field and MarlandCO2 will rise 3.3% a year

Tipping point

2008: Aufhammer and CarsonChina’s CO2 emission growth may be underestimated

Ice core analysis of air pollutants

•60% of CH4 emission are a result of humans

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

CarbonDioxide

Methane

Temp.

Sea Level

The Atmosphere Is Warming Mostly Because of Human Activities

1988-Intergovernmental Panel on Climate Change (IPCC)90–99% likely that lower atmosphere is warming1906–2005: Ave. temp increased about 0.74˚C (1.3˚F)1970–2005: Annual greenhouse emissions up 70%Past 50 years: Arctic temp rising almost twice as fast as the rest

of the earthMelting of glaciers and floating sea iceProlonged droughts: increasingLast 100 years: sea levels rose 10–20 cm

2007-Al Gore and the IPCC : Nobel Peace Prize“…the earth has a fever. And the fever is rising… We are

what is wrong, and we must make it right”

What natural and human-influenced factors could have an effect on temperature changes?Amplify (give positive feedback)Dampen (give negative feedback to)

Simplified Model of Some Major Processes That Interact to Determine Climate

Melting of Alaska’s Muir Glacier between 1948 and 2004

Comparison of Measured Temperature from 1860–2007 and Projected Changes

Is a Hotter Sun the Culprit?Energy output from the sun affects the

earth’s temperature.Since 1975

Lower atmosphere (Troposphere) has warmedStratosphere has cooled

This is not what a hotter sun would do!!Atmosphere is heating from the bottom

up…this indicates inputs at earth’s surface (from human activities) are the main cause.

Can the Oceans Save Us?Solubility of CO2 in ocean water

But, solubility of gases decreases as temp. of water increase

Help moderate temperature-remove 25-30% CO2

Warmer oceansCO2 levels increasing acidity

Effect on atmospheric levels of CO2

Effect on coral reefs - ability of to make shells, could dissolve shells

Antarctica’s Southern Ocean (largest CO2 sink and the North Atlantic Ocean

Decrease in CO2 uptake

Significance on global CO2 levels

Temperature, acidity, and the ability to absorb CO2

from atmosphere are changing due to humans. This can accelerate global warming.

Uncertainty about the Effects of Cloud Cover on Global WarmingWarmer temperatures increase evaporation and

create more cloudsThick, light-colored low altitude clouds: decrease surface

temperatureThin, cirrus clouds at high altitudes: increase surface

temperature

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

Outdoor Air Pollution Can Temporarily Slow Global Warming

Aerosols (suspended microscopic droplets of solid particles) and soot pollutantsMost light-colored sulfate particles

produced by fossil fuel combustion tend to reflect incoming light- also serve as condensation nuclei and form clouds (more cooling)

BUT black carbon particulate matter emitted by diesel exhaust, burning forest and cooking fuels warms the atmosphere more than estimated

Scientists do not expect aerosols or soot pollutants to enhance or counteract projected global warming1. Fall back to the earth or are washed out of the lower atmosphere within weeks, where as CO2 remains in the atmosphere for as long as 120 years!

2. Reduction: especially in developed countries

Hmmm.. The decrease in some aerosols’ concentrations increase global warming!

Enhanced Global Warming Could Have Severe Consequences

Why worry about it? How much and how fast

Tipping point and irreversible climate change

Worst-case scenariosEcosystems collapsingLow-lying cities floodedWildfires in forestsProlonged droughts: grasslands become dust

bowlsMore destructive stormsGlaciers shrinking; rivers drying up

Projected Effects of Global Warming and the Resulting Changes in Global Climate

19-2 Severe Drought Is Increasing: The Browning of the EarthDrought=evaporation exceeds precipitation

Accelerate global warming, lead to more drought

Biodiversity will decrease

NPP will decrease

Dry climate ecosystems will increase

Positive feedback-accelerate global warming and climate change= more drought

Ice and Snow Are MeltingWhy will global warming be worse in the polar regions?Light colored ice and snow=reflect solar energy-cool earthMelting exposed dark land=absorb more solar energy=polar

are heat up

Important climate role of floating sea ice-precipitation

Mountain glaciers affected byAverage snowfallAverage warm temperatures

Europe’s AlpsGlaciers are disappearing

South AmericaGlaciers are disappearing

GreenlandWarmer temperatures

Sea Levels Are Rising2007 IPPC-sea level will rise 18-59 cm this century

Expansion of warm water

Melting of land-based ice

What about Greenland? 1-2 meters from 2050-2010

Projected irreversible effectDegradation and loss of 1/3 of coastal estuaries, wetlands, and

coral reefsDisruption of coastal fisheriesFlooding of

Low-lying barrier islands and coastal areasAgricultural lowlands and deltas

Contamination of freshwater aquifersSubmergence of low-lying islands in the Pacific and Indian

Oceans and the Caribbean

Areas of Florida to Flood If Average Sea Level Rises by One Meter

Permafrost Is Likely to Melt: Another Dangerous Scenario

Carbon present as CH4 in permafrost soils and lake bottoms

2004: Arctic Climate Impact Assessment10–20% of the permafrost might melt this century

Effect on global warming

Ocean Currents Are Changing but the Threat Is Unknown

Melting glaciers, particularly in Greenland

Increased rain in the North Atlantic

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

Prolonged rains and flooding in other areas

Will storms get worse? More studies needed

Hurricanes Katrina and Rita

Global Warming Is a Major Threat to Biodiversity

Most susceptible ecosystemsCoral reefsPolar seasCoastal wetlandHigh-elevation mountaintopsAlpine and arctic tundra

What aboutMigratory animalsForests

Which organisms could increase with global warming? Significance?Insects FungiMicrobes

Climate Change Will Shift Areas Where

Crops Can Be GrownRegions of farming may shift

Decrease in tropical and subtropical areasIncrease in northern latitudes

Less productivity; soil not as fertile

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 causeIncreased floodingIncrease in some forms of air pollution, more O3

More insects, microbes, toxic molds, and fungi

19-3 Dealing with Climate Change Is DifficultGlobal 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

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?

Avoiding Catastrophe: We Can Reduce the Threat of Climate Change

Input or prevention strategies

Improve energy efficiency to reduce fossil fuel use

Stop cutting down tropical forests

Output strategyCapture and store CO2

Socolow and PacalaClimate stabilization wedges Keep CO2 emissions to 2007 levels by 2057

Brown: need to do moreCut CO2 emissions by 80% by 20202008 book: Plan B 3.0: Mobilizing to Save Civilization

Output solutionsMassive global tree

planting; how many?

Wangari Maathai

Great Wall of Trees: China and Africa

Plant fast-growing perennials on degraded land

Capturing and storing CO2

Fifteen Ways to Cut CO2 Emissions

Some Output Methods for Removing CO2 from the Atmosphere and Storing It

Should We Use Geo-Engineering Schemes to Help Slow Climate

Change?CCS-Carbon capture and storage

Injection of sulfate particles into the stratosphereWould it have a cooling effect?Would it accelerate O3 depletion?

Remove HCl from seawaterEffects on ecology?

Pump up nutrient-rich deep ocean water and cause algal blooms

Re-ice the Arctic

If any of these fixes fail, what about a rebound effect?

How Much Will It Cost to Slow Climate Change?

Short-term costs lower

Local and global economies may be boosted

Governments Can Help Reduce the Threat of Climate Change

Strictly regulate CO2 and CH4 as pollutants

Cap-and-trade approach

Increase subsidies to encourage use of energy-efficient technology

Technology transfer

We Can Move Beyond the Kyoto Protocol2004: Stewart and Wiener

New treaty needed

Should be led by the U.S.

Include the developing countries

Cap-and-trade emissions program

Set up 10 year goals

Some Governments Are Leading the WayCosta Rica: goal to be carbon neutral by 2030

Norway: aims to be carbon neutral by 2050

China and India must change energy habits

U.S. cities and states taking initiatives to reduce carbon emissions

Some Companies and Schools Are Reducing Their Carbon Footprints

Major global companies reducing greenhouse gas emissionsAlcoaDuPontIBMToyotaGEWal-Mart

Fluorescent light bulbsAuxiliary power units on truck fleets

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

What can you do?

We Can Prepare for the Harmful Effects of Climate Change

Reduce greenhouse gas emissions as much as possible

Move people from low-lying coastal areas

Limit coastal building

Remove hazardous material storage tanks away from the coast

Genetically engineer crops more tolerant to drought

Stockpile 1–5 years of key foods

Waste less water

Connect wildlife reserves with corridors

Our Use of Certain Chemicals Threatens

the Ozone LayerOzone Thinning Seasonal depletion in

the stratosphereAntarctica

and Arctic

1930: MidgelyDiscovered the first CFC

1984: Rowland and Molina CFCs were depleting O3

Other ozone-depleting chemicals

Global Average Total Ozone Values in the Stratosphere from 1979–2005

Why Should We Worry about Ozone Depletion?

Damaging UV-A and UV-B radiation Increase eye cataracts and skin cancer

Impair or destroy phytoplanktonSignificance?

We Can Reverse Stratospheric Ozone DepletionStop producing all ozone-depleting chemicals

60–100 years of recovery of the O3 layer

1987: Montreal Protocol

1992: Copenhagen Protocol

Ozone protocols: prevention is the keySubstitutes for CFCs are available

More are being developed

HCFC-22Substitute chemicalMay still be causing ozone depletion

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