Download Climate Control and Ozone Depletion

Climate Control and Ozone Depletion
Chapter 19
Vocabulary
Carbon Capture and Storage
Objective 1
How Might the Earth’s
Temperature and Climate
change in the future?
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 cooling and global warming respectively
• Over the past 10,000 years
– Interglacial period
• Characterized by a fairly stable climate and a fairly steady
average global surface temperature
• Over the past 1,000 years
– The average temperature of the atmosphere has
remained fairly stable but began to rising during the last
century
Estimated Changes in the Average
Global Temperature of the
Atmosphere
Our Climate, Lives, and Economies Depend
on the Natural Greenhouse Effect
• Without the natural greenhouse effect
– Earth would be cold and uninhabitable
• Primary Greenhouse Gases
– Water Vapor H2O
– Carbon Dioxide CO2
– Nitrous Oxide NOx
– Methane CH4
Human Activities Emit Large Quantities of
Greenhouses Gases
• Since the Industrial Revolution (275 years ago)
– CO2, CH4, and N2O emissions higher in lower atmosphere
– Main sources:
• agriculture, deforestation, and burning of fossil fuels
• Correlation of rising CO2 and CH4 with rising global
temperatures and sea levels
• Countries with the largest CO2 emissions (in order)
– US, China, the European Union (with 27 countries),
Indonesia, Russia, Japan, and India
• Scientific and economic studies
– 2007: Field and Marland
• Tipping point – the irreversible estimated threshold for large
scale climate changes
– CO2 levels exceeding 450 ppm
– In 2007 CO2 levels were 384 ppm
• Ice core analysis of air pollutants
– 60% of methane emissions during the last 275 years are
the result of human activity
– Nitrous Oxide emissions have risen about 20%
Ice Cores Are Extracted by Drilling Deep
Holes in Ancient Glaciers
Atmospheric
Levels of CO2
Atmospheric
Levels of CH4
Temperatures
Sea Levels
The Atmosphere Is Warming Mostly Because of
Human Activities
• Intergovernmental Panel on Climate Change (IPCC)
– Very likely (90–99%) that lower atmosphere is warming
and that human activities are responsible for most of the
recent temperature increase
• 2007 IPCC report
– 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
Melting of Alaska’s Muir Glacier
between 1948 and 2004
The Big Melt: Some of the Floating Sea
Ice in the Arctic Sea
Simplified 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
– Troposphere has warmed
– Stratosphere has cooled
– If you increase the output from the sun, you increase the
amount of energy that arrives at the top of the Earth’s
atmosphere and get heating throughout the atmosphere
• This is not what a hotter sun would do
Can the Oceans Save Us?
• The world’s oceans have absorbed about half of all the
CO2 released to the atmosphere since the beginning of
the Industrial Revolution
• Warmer oceans
– CO2 levels increasing acidity by 30%
• CO2 + H2O  H2CO3 (Carbonic Acid)
– Effect on atmospheric levels of CO2
– Decrease ability of corals to make CaCO3 shells and bodies
• Antarctica’s Southern Ocean & North Atlantic Ocean
– Solubility of CO2 decreases with increasing temperature
Cancun Mexico
There Is Uncertainty about the Effects of Cloud Cover
on Global Warming
• Warmer temperatures create more clouds
– Thick, light-colored low altitude clouds
• decrease surface temperature
– Thin, cirrus clouds at high altitudes
• increase surface temperature
• Effect of jet entrails on climate temperature
– NASA scientists found that jet contrails expand and turn
into large cirrus clouds that tend to release heat
Objective 2
What Are Some Possible Effects of a
Warmer Atmosphere?
Enhanced Global Warming Could Have
Severe Consequences
• 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
Projected Effects of Global Warming and the Resulting Changes in Global Climate
Ice and Snow Are Melting
• Why will global warming be worse in the polar regions?
– The arctic sea ice plays an important role in the earth’s climate by
affective the average amount of precipitation
• Important climate role of floating sea ice
– Because ice is floating, it does not increase sea level when it melts
– Rising sea levels will come from land-based ice that melts
• Mountain glaciers affected by two factors
– Average snowfall – adds to their mass
– Average warm temperatures – take mass away (melt)
Science Focus: Melting Ice in Greenland
• Largest island
– 80% composed of glaciers
• Some up to 2 miles deep
– Population = 60,000 people
• The glaciers contain ~10% of the world’s fresh water
• 1996–2007: net loss of ice doubled
Areas of Glacial Ice Melting in Greenland during Summer 1982–2007 Increased
Sea Levels Are Rising
• According to the 2007 IPCC report, the world’s
average sea level is very likely (90-99% certainty) to
rise 18-59 centimeters (0.6 – 1.9 feet) during this
century.
– Expansion of warm water
• About 2/3rds of the increase will result from the expansion of
water as it warms
– Melting of land-based ice
• About 1/3rd of the increase will result from land ice melting
• Projected irreversible effects
– 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
– In US
» Louisiana, North Carolina, Texas, and South Carolina
• Agricultural lowlands and deltas
– Coastal areas where much of the world’s rice is grown
– Contamination of freshwater aquifers
• With salt water
• Decreased supply of groundwater
– Currently used for irrigation, drinking, and cooling power plants
– Submergence of low-lying islands in the Pacific and Indian
Oceans and the Caribbean
• Home to 1 of every 20 of the world’s people
Areas of Florida, U.S., to Flood If Average Sea Level Rises by One Meter
Low-Lying Island Nation: Maldives in the Indian Ocean
Permafrost Is Likely to Melt:
Another Dangerous Scenario
• Carbon present as CH4 in permafrost soils and lake
bottoms
– 50-60 times the amount emitted as CO2 from burning fossil
fuels each year
Permafrost
Layer in soil and lake bottoms melts, significant
– If the permafrost
amounts of methane will be released into the atmosphere.
• 2004: Arctic Climate Impact Assessment
– 10–20% of the permafrost might thaw this century
Projected Decline in Arctic Tundra in Portions of Russia from 2004 to 2100
Ocean Currents Are Changing but the Threat Is Unknown
• Ocean Currents transfer CO2 and warm water
between the tropics and the poles
– This can cause
• Melting glaciers, particularly in Greenland
• Increased rain in the North Atlantic
– Could add enough fresh water to the ocean to slow the currents
Extreme Weather Will Increase in Some Areas
• Heat waves and droughts will increase in some areas
– Kill large numbers of people
– Reduce crop production
– Expand deserts
• Prolonged rains and flooding in other areas
• Will storms get worse?
– More studies needed before conclusions are drawn
– Hurricane Katrina
• Occurred in 2005 when Atlantic waters were especially warm
Global Warming Is a Major Threat to Biodiversity
Most susceptible ecosystems
High-elevation mountaintops
Coastal wetland
Polar seas
Coral reefs
Alpine and arctic tundra
Changes in Average Ocean Temperatures, Relative to
Coral Bleaching Threshold
• What about
– Migratory animals
• Biological clocks of birds and whales will be disrupted
– Forests
• Forest fires will increase
• Oak-Pine and Oak-Hickory forests may expand northward
• Which organisms could increase with global
warming?
– Insects
• Pine Beetle: Damage Trees
– Fungi
• Damage Trees
– Microbes
Exploding Populations of Mountain Pine Beetles in
British Columbia, Canada
The Brown Trees are Dead
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
• Less productivity; soil not as fertile
Climate Change Will Threaten the Health of Many People
• Deaths from heat waves will increase
– Summer 2003 – 52,000 Europeans killed in heat wave
– BUT, 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
Objective 3
What Can We Do to Slow Climate
Change?
Dealing with Climate Change Is Difficult
• Global problem
– International cooperation is required to deal with the threat
• Long-lasting effects
– CO2 emitted from burning coal last about 120 years
– Once set into motion, irreversible climate change will last hundreds to
thousands of years
• Long-term political problem
– Voters and Elected officials generally respond well to short-term
problems
• Harmful and beneficial impacts of climate change unevenly spread
– Higher latitude nations will have higher crop yields, fewer crop yields, ,
fewer deaths in winter, lower heating bills, and more tourism
• Many proposed actions disrupt economies and lifestyles
– Phasing out fossil fuels
What Are Our Options?
• Two approaches or a mixture of both
– Drastically reduce the amount of greenhouse gas emissions
• To slow down rate of warming in time to prevent climate changes
– Devise strategies to reduce the harmful effects of global
warming
• Recognize that some warming is unavoidable
• Will we reach a political tipping point before we reach
irreversible climate change tipping points?
– Political tipping point = pressure could force elected officials
and business leaders to implement solutions on an urgent
basis to avoid reaching irreversible climate change
Avoiding Catastrophe: We Can Reduce the Threat of
Climate Change
3 major input or prevention strategies
1) Improve energy efficiency to reduce fossil fuel use
2) Stop cutting down tropical forests
3) Shift from non renewable carbon-based fossil fuels
to a mix of carbon-free renewable energy
A 4th strategy – which is an output strategy
4) Keep burning fossil fuels, but capture and store CO2 in soil,
in vegetation, underground, and in the deep ocean
 Then hope that it will never leak out
• US scientists Socolow and Pacala
– Have outlined at plan to keep CO2 emissions to 2007
levels by 2057
• Climate stabilization wedges
– 15 different strategies that would reduce CO2 emissions
• Swedish scientist Brown says we need to do more
– Cut CO2 emissions by 80% by 2020
– Plant 4 billion trees
• Assuming ½ will survive
– Plant large areas of degraded land with fast growing
perennial plants
Page 515 of text
Fifteen Ways to Cut CO2 Emissions
Page 515 of text
Some Output Methods for Removing CO2 from the
Atmosphere and Storing It
Case Study: Is Capturing and Storing CO2 the Answer?
• Carbon capture and storage (CCS)
– removing CO2 from the smokestacks of coal burning power
and industrial plants and then store it somewhere
• Several problems with this approach
– Power plants using CCS
• More expensive to build
• None currently exist
– Unproven technology – removes only part of the CO2
– Large inputs of energy to work
• Increasing CO2 emissions and cancel out the goal of CCS
– Promotes the continued use of coal (world’s dirtiest fuel)
– Government subsidies and tax breaks could be used to
promote Solar, wind, geothermal, and other renewable
sources
– Stored CO2 would have to remain sealed forever: no leaking
Should We Use Geo-Engineering Schemes to Help Slow
Climate Change?
• CCS is one proposed geo-engineering scheme
– Long-term effects unknown
• Injection of sulfate particles into the stratosphere
– Use balloons and jet planes
– This could (in theory) reflect some of the sun’s light
– Would it have a cooling effect?
– Would it accelerate O3 depletion?
– There are a lot of unknown effects
Pollution makes me sick!
• Remove HCl from seawater
– To reduce ocean acidity
• Pump up nutrient-rich deep ocean water
– Anchor huge vertical pipes in the sea to pump nutrient
rich water to fertilize algae
– This would remove CO2 from the atmosphere and emit
dimethyl sulfide
• Could contribute to production of low clouds that would reflect
sun
• Re-ice the Arctic
– Tow 800,000 ice-making barges to the Arctic each year
Governments Can Help Reduce the Threat of Climate
Change
• Strictly regulate CO2 and CH4 as pollutants
• Cap-and-trade approach
– Put a cap on the amount of CO2 and CH4 emissions in a country ,
issue permits to emit these pollutants, and then let polluters trade
their permits in the marketplace
• Increase subsidies to encourage use of energy-efficient
technology
• Technology transfer
– Governments of developed countries could help fund the transfer
of the latest green technologies to developing countries
Governments Can Enter into International Climate
Negotiations: The Kyoto Protocol
• 1997: Treaty to slow climate change
– 174 of the world’s 194 countries (not the US)
• The Kyoto Protocol
– Reduce emissions of CO2, CH4, and N2O to levels of 1990
by 2012
– Trading greenhouse gas emissions among countries
– Not signed by the U.S.
• President G.W. Bush’s reasons
– Harm the US economy
– Did not require emission reduction by developing countries
» China, India, or Brazil
We Can Move Beyond the Kyoto Protocol
• 2004: Stewart and Wiener
– Countries should work together to form a new treaty
• Should be led by the U.S.
– The Kyoto Protocol would have little effect on future global
warming without support and action by the US, China, India,
Brazil, and Indonesia
• Cap-and-trade emissions program
– Include developing countries omitted from the trading plan
originally
• Set up 10 year goals
– Over the next 40 years
Some Governments Are Leading the Way
• Costa Rica: goal to be carbon neutral by 2030
• Norway: aims to be carbon neutral by 2050
• If China and India continue their massive coal burning and
other high-carbon activities, the world will not be able to
avoid the projected harmful effects of climate change
• 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
emissions
– Alcoa
– DuPont
– IBM
– Toyota
– GE
– Wal-Mart
• Fluorescent light bulbs
• Auxiliary power units on truck fleets
• Overhead passive solar lighting (Valrico and 60)
• What is your carbon footprint?
– Nature.org/climatecalculator
– Epa.gov/climatechange/emissions/ind_calculator.html
– Carbonfootprint.com
– Gocarbonzero.org
• What can you do?
– Nativeenergy.com
– My-climate.com
– Climatecare.org
– Carbon-clear.com
We Can Prepare for the Harmful Effects of
Climate Change
•
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•
•
•
•
•
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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
Ways to Prepare for the Possible LongTerm Harmful Effects of Climate Change
Objective 4
How Have We
Depleted O3 in
the
Stratosphere
and
What Can We
Do?
Our Use of Certain Chemicals Threatens the Ozone
Layer
• Ozone Thinning
– Ozone depletion varies with altitude and location
– Seasonal depletion in the stratosphere
• Antarctica and Arctic
• 1930: Midgely
– Discovered the first CFC
– Chemically unreactive, inexpensive, odorless, nonflammable,
nontoxic, and noncorrosive compounds seemed to be the
dream chemical
• 1984: Rowland and Molina
– CFCs were depleting O3
Global Average Total Ozone Values in the
Stratosphere from 1979–2005
Massive Ozone Thinning over Antarctica in 2007
Summary of CFCs and Other ChlorineContaining Compounds that Destroy Ozone
Why Should We Worry about Ozone Depletion?
• Damaging UV-A and UV-B radiation will reach
earth’s surface
– Increase eye cataracts and skin cancer
• Impair or destroy phytoplankton
– Significance?
• Phytoplankton are responsible for 50% of the O2 produced in
the world
Structure of the Human Skin and the Relationship
between UV and Skin Cancer
Fig. 19-E (2), p. 526
What Can You Do? Reducing Exposure
to UV Radiation
We Can Reverse Stratospheric Ozone Depletion
• Stop producing all ozone-depleting chemicals
• 60–100 years of recovery of the O3 layer
• 1987: Montreal Protocol
– Cut CFC emissions by 35% between 1989 and 2000
• 1992: Copenhagen Protocol
– An amendment that phased out key ozone-depleting
chemicals
• Ozone protocols: prevention is the key
– Use prevention to solve environmental problems
• Substitutes for CFCs are available
SUMMARY
List five ways in which you can reduce your carbon
footprint.
What are the four major strategies for slowing
projected climate change?
How can positive feedback loops affect future temperature
changes and thus global temperature?