Transcript Environmental Science

Climate Control and Ozone Depletion
 Our Earth!
An Enormous Cloud of Air Pollutants and
Ash from Mt. Pinatubo on June 12, 1991
Volcanoes Change Worldwide Climate

Mount Pinatubo exploded releasing airborne pollutants and ash resulting in deaths and damage of
farmlands and homes
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Volcanoes affect worldwide temperature by cooling (clouds); after the pollutants leave,
temperatures return to normal (remember the Iceland volcano that halted planes for a week)
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Climate will change because of the release of the volcanic gases – Year without summer in the
1816 – 1815 eruption of Mount Tambora in the Dutch East Indies (Indonesia), the largest known
eruption in over 1,300 years
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Climatic models indicate that global temperatures will rise because of greenhouse gasses
affecting climate and the human way of life
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Primary question: “What should we do about it?”
Global Warming and Global Cooling
Are Not New
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Over the past 4.7 billion years the climate has been altered by: volcanic emissions; changes in
solar input; movement of continents; and impacts by meteors
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Over the past 900,000 years: Earth has experienced prolonged periods of Global Cooling and
Global Warming; these alternating freezing and thawing cycles are Glacial and Interglacial
(between ice ages) periods
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Over the past 10,000 years: Earth is in an Interglacial Period of fairly stable climates and roughly
the same temperatures; this allowed agriculture, cities and the human population to flourish
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Over the past 1,000 years: temperatures have remained stable except for the past century when
we started to remove more forest and burn fossil fuel increasing global temperatures
Estimated Changes in the Average
Global Temperature of the Atmosphere
Human Activities Emit Large Quantities
of Greenhouses Gases
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Without the Natural Greenhouse Effect (Ozone Layer) which warms the lower atmosphere and
surface, the Earth would be a cold and uninhabitable earth
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Since the Industrial Revolution:
• Greenhouse Gasses: CO2, CH4, and N2O increased
• Main Sources: agriculture, deforestation, and burning of fossil fuels
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Correlation of Rising CO2 and CH4 with rising global temperatures during the past 400,000
years and the rising of the global sea level
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Countries with the largest CO2 emissions: US, China, European Union (with 27 countries),
Indonesia, Russia, Japan and India; with the US responsible for 25% of the world’s cumulative
emissions, China 5%
Atmospheric Levels of CO2 and CH4,
Global Temperatures, and Sea Levels
The Atmosphere Is Warming Mostly
Because of Human Activities
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Intergovernmental Panel on Climate Change (IPCC)
• Includes 2500 climate expects from 130 nations
• Its 2007 report is based on 29,000 pieces of data since 2002:
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90–99% likely that lower atmosphere is warming
1906–2005: Ave. temp increased about 0.74˚C (1.3 F); greatest since 1980
1970–2005: Annual greenhouse emissions up 70%; carbon dioxide levels are higher than in
650,000 years
Past 50 years: Arctic temp rising almost twice as fast as the rest of the earth
Melting of glaciers and floating sea ice (Arctic Ocean)
Prolonged droughts; changing rain patterns
Last 100 years: sea levels rose 10–20 cm (4-8 inches)
Melting of Alaska’s Muir Glacier
between 1948 and 2004
Can the Oceans Save Us?
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Oceans Absorb CO2 (25-30%); but the solubility of CO2 in ocean water decreases with increasing
temperature
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Bad News: Warmer Oceans:
• CO2 levels increasing acidity – example is carbonic acid in sodas
• As the oceans are not absorbing as much CO2, this further accelerates global warming by
increasing atmospheric CO2
• Effects coral reefs – acid prevents them from making shells (calcium carbonate)
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As Antarctica’s Southern Ocean and the North Atlantic Ocean warms:
• Largest sink for removing it – further decreasing in CO2
• Significance on global CO2 levels needs to be established
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Good News: Atlantic Deep Ocean has increased productivity by 15%; phytoplankton may be
increasing due to the warmer waters
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The inability of the oceans to absorb carbon dioxide can intensify and accelerate global warming
and climate change.
Enhanced Global Warming Could Have
Severe Consequences
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Not concerned with normal swings in daily weather, but in the projected, very rapid, global
change in climate – decades, centuries or millennia from now – How rapidly will it change?
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Key Problem: projected rapid increase in the average temperature during this century – we don’t
know the answer?
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Tipping Point: When will it be too late to reverse changes that result from climate change?
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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
Severe Drought Is Increasing:
The Browning of the Earth
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Drought
• Occurs when evaporation from increasing temperatures exceeds precipitation for a long
period
• Areas of severe drought has increased from about 15% to 30% - total area the size of Asia
from 1979 to 2002
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Less Moisture in the Soil:
• Steam flow and available surface water declines can result in drought
• Less vegetation and net productivity and biodiversity will decrease
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Dry Climate Ecosystems Increase:
• Savannas, chaparrals, deserts
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Other Effects:
• Fires
• Food shortages
• Mass migrations and deaths (not only of people but animals, plants and other organisms)
Ice and Snow Are Melting
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Polar Regions help to cool the Earth:
• Light color ice and snow help to reflect the sun’s energy
• Melting exposes darker surfaces increasing absorbance of solar energy – driveway in snow
• Polar regions will melt quicker, exposing more land, etc
• Can result in a runaway positive feedback loop
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Losing Ice in both mountain glaciers and polar ice caps
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Important Climate Role of Sea Ice:
• Lose can result in changing precipitation patterns (less in US, more in Europe)
• Floating sea ice does not contribute to rising waters but land base Arctic ice that melts will
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Mountain Glaciers Affected By:
• Average snowfall and warm temperatures; as the melt, they provide fresh water but what will
occur after they have melt?
• Also, releasing fresh water into the oceans, what affect will that have?
The Big Melt: Some of the Floating Sea
Ice in the Arctic Sea
Areas of Glacial Ice Melting in Greenland
during Summer 1982–2007 Increased
Sea Levels Are Rising
The World’s Sea Levels are very likely to:
• Rise 0.6-1.9 ft during this century and continue to rise
• About 2/3’s will result from the expansion of warm water and 1/3 from land based ice
(glaciers)
• Others suggest 3.3-6.6 ft; and if glaciers in Greenland rich a tipping point, 20 ft.
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Projected Irreversible Effect:
• 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 (US East, Gulf coast; states most affected –
LA, FL, NC, TX and SC (sand hills?))
• Agricultural lowlands and deltas where rice is grown
• Contamination of freshwater aquifers from salt and brackish water – water supplies,
irrigation, drinking
• Submergence of low-lying islands in the Pacific and Indian Oceans and the Caribbean (1 in
20 people)
• Flooding of coastal cities and displacement of at least 100 mil people
NYC Under Water
NYC Under Water!
Areas of Florida, U.S., to Flood If Average
Sea Level Rises by One Meter
Projected Decline in Arctic Tundra in
Portions of Russia from 2004 to 2100
Ocean Currents Are Changing but the
Threat Is Unknown
Shallow and Deep Ocean Currents:
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Connected and move like a giant conveyer belt transferring warm and cold water between the
surface and the deeps and from the tropics to the poles
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Melting glaciers (Greenland), can add fresh water to the oceans as can increased rain in the North
Atlantic
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Will the fresh water disrupt the currents? What affect would this then have on climates
(ocean biodiversity)?
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Not thought to be an immediate problem on the ocean currents but more research is needed
Extreme Weather Will Increase in Some
Areas
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Extreme Weather:
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Such as heat waves and droughts in some areas will increase killing large numbers of
people, reduce crop production and expand deserts
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Prolonged rains and flooding in other areas
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Will storms get worse? Not known
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Hurricanes: warmer water will fuel them but also increased wind shear in the Atlantic may
inhibit
Global Warming Is a Major Threat to
Biodiversity
Changes in Climate from Global Warming is affecting physical and biological ecosystems on all
continents; a warmer climate can expand the habitat of many including weeds, insect pest like fire
ants, and other disease carrying organisms
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30% of the land and animal based Species Can Disappear if the chance exceeds 2.5-4.5 F; 70%
if 6.3 F; hardest hit is the colder climates (polar bear, penguins)
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Also, disrupt the Biological Clocks of Birds, whales and other migratory species; wrong place at
the wrong time
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Most Susceptible Ecosystems: coral reefs; polar seas; coastal wetland; high-elevation
mountaintops; and alpine and arctic tundra
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Forest may not be able to move quick enough: Arctic forests will decline but the oaks may be able
to move quickly and expand northward
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Which Organisms Could Increase with global warming? Significance? Insects (pine beetles);
Fungi and Microbes
Exploding Populations of Mountain Pine
Beetles in British Columbia, Canada
Climate Change Will Shift Areas Where
Crops Can Be Grown
Farming more than any other activity depends on a stable environment; drastic changes may occur
do to shifting climates and a faster hydrologic cycle
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Regions of Agricultural Productivity (farming) may shift:
• Decrease in tropical and subtropical areas
• Increase in northern latitudes if temps rise 1.8-5.5 F
• Less productivity (less food); soil not as fertile
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There could be a 10-15% drop in rainfall in the US and other parts of the world; it is hoped that
Genetically Engineered Varieties of key food crops could be developed that are more tolerant to
drought and “climate”
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Food Production could decline along rivers fed by snow; arid and semiarid areas where drought
will increase; and humid areas (SE Asia – monsoons)
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Food May Be Plentiful because of longer growing seasons in the northern regions but by 2050,
200-600 mil of the world’s poorest and most vulnerable can face starvation and malnutrition
What Are Our Options?
Addressing climate change could be one of the most urgent scientific, political, economic and ethical
issues we face:
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Global Problem: international cooperation
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Long-lasting effects: climate changes due to excessive greenhouse gasses will last hundreds
to thousands of years
Long-term political problem not short term; most of the people that will suffer the most harm
haven’t been born yet
Two Approaches: most agree it’s a combination of both:
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Drastically Reduce the Amount of Greenhouse Gas Emissions to slow down the rate of
warming in time to prevent global climate changes
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Recognize that Some Aspects are Unavoidable and to devise strategies to reduce the
harmful effects
Will we reach a Political Tipping Point when enough individuals exert sufficient political and
consumer pressure (through their purchases) to their politicians and business leaders before we
reach irreversible Climate Change Tipping Points?
Solutions: Global Warming, Methods for
Slowing Atmospheric Warming
Fifteen Ways to Cut CO2 Emissions
Governments Can Enter into International
Climate Negotiations: The Kyoto Protocol
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1997: 161 nations meant to negotiate a treaty to slow climate change; into effect in 2/05 with 174
of 194 countries (not the US) ratifying the agreement
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The Kyoto Protocol:
• Reduce emissions of CO2, CH4, and N2O to at least 5.2% below their levels of 1990 by 2012
of 36 participating developed countries; developing nations were excluded as this may hinder
economic growth including China and India
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Trading greenhouse gas emissions among countries; plant trees if you are emitting
greenhouse gases; but this didn’t work as it may actually encourage emissions
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Not signed by US: Bush’s reasons: harm the US economy; did not require developing
nations as China or India to reduce theirs
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Most analysts and 59% of the Americans in a 1997 poll stated we should use our influence to
improve the treaty rather than weaken and abandon it
Some Governments Are Leading the Way
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Costa Rica: goal to be Carbon Neutral by cutting its net carbon emissions to zero by 2030;
generates 78% of its power with renewable hydroelectric power and another from 15% from wind
and geothermal
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Norway: aims to be carbon neutral by 2050
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China and India
• Must change energy habits by “leapfrogging” over traditional forms of economic development
such as coal burning and become leaders in designing, manufacturing and selling cleaner
power systems, appliances, cars and homes
• “Green Technologies” will make up most of the future industries
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U.S. cities and states taking initiatives to reduce carbon emissions – solar and wind power,
bicycles trails, mass transit
What Can You Do? Reducing CO2
Emissions
Ways to Prepare for the Possible LongTerm Harmful Effects of Climate Change
Ozone Layer
Ozone in the lower stratosphere keeps 95% of the sun’s harmful UV-rays (UV-A, UV-B) from hitting
the Earth
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Ozone Thinning (Ozone Hole):
• 40-50% seasonal depletion in the stratosphere in Antarctica and Arctic (some up to 100%);
thinning in other regions except the tropics; worst between 2010-2019
• When the seasonal thinning ends, huge masses of ozone move and they linger over
Australia, New Zealand, Africa and South America; increasing UV-B levels by 3-10%
• Similar hole in the Arctic from Feb to June; 11-38%
• Thinning can cause a serious threat humans, animals and plants (producers) that use
sunlight to support food webs
• CFC (chlorofluorcarbon); Freons; dream chemicals; coolants; propellants in aerosol spray
cans and fumigants responsible for 75-85% of depleted O3
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Good News: in 60–100 years, the ozone layer will return to pre-1950 levels (possibly by 2068)
Natural Capital Degradation: Massive
Ozone Thinning over Antarctica in 2007
Natural Capital Degradation: Effects of
Ozone Depletion