Climate Change and Ozone Loss

Climate Change and Ozone Loss Chapter 16 Peter Cohn, Taylor Feld, and Elliott Schwimmer

Climate modeling Hansen’s model In June of 1991, Mount Pinatubo exploded after 600 years of slumber, causing many people to die and clouds of ashes to swell into the atmosphere. NASA scientist, James Hansen predicted using his model of climate change, that the explosion would cause Earth’s temperature to decline on average by 1 degree F. This proved that the models were quite accurate and ascertained that global warming was a very real threat. It convinced and forced scientists and lawmakers to take global warming seriously as it is a big challenge for humanity. Studying a Volcano to Understand Climate Change Fig. 16-1, p. 367

Average Global Temperature over the Past 900,000 Years 17 16 15 14 Average surface temperature (°C) 13 12 11 10 9 900 800 700 600 500 400 300 200 100 Present Thousands of years ago Fig. 16-2a, p. 369

Average temperature over past 10,000 years = 15°C (59°F) Temperature Changes Over Past 22,000 Years 2 Agriculture established 1 0 –1 Temperature change (°C) – 2 End of last ice age – 3 – 4 – 5 20,000 10,000 2,000 1,000 200 100 Now Years ago Fig. 16-2b, p. 369

Temperature Changes Over Past 1,000 Years 1.0 0.5 0.0 Temperature change (°C) –0.5 –1.0 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2101 Year Fig. 16-2c, p. 369

Average Global Temperature Over Past 130 Years 15.0 14.8 14.6 14.4 Average surface temperature (°C) 14.2 14.0 13.8 13.6 1860 1880 1900 1920 1940 1960 1980 2000 2020 Year Fig. 16-2d, p. 369

Past Climate Change • Climate change in the span of Earth’s life time isn’t unusual or new. It has been changed by volcanic eruptions, meteors, plate tectonics, etc. • There are both natural global cooling (glacial) and global warming (interglacial) periods. Times when the earth cools are known as ice ages, when ice covers the earths surface for close o 100,000 years. • During this warm period, however, climate has changed considerably. • Ice cores, or chunks or ice taken from the deep core of glaciers can give us clues about the past climates. • The Greenhouse Effect also plays a role as the most accepted theory related to global warming as it heats up the atmosphere and is a natural phenomenon, but is happening in elevated levels due to human interference. • Two of the most abundant greenhouses are water vapor and carbon dioxide.

Ice Cores: Records of Past Climates Fig. 16-3, p. 369

Greenhouse Effect (b) The earth's surface absorbs much of the incoming solar radiation and degrades it to longer-wavelength infrared (IR) radiation, which rises into the lower atmosphere. Some of this IR radiation escapes into space as heat and some is absorbed by molecules of greenhouse gases and emitted as even longer wavelength IR radiation, which warms the lower atmosphere. (c) As concentrations of greenhouse gases rise, their molecules absorb and emit more infrared radiation, which adds more heat to the lower atmosphere. (a) Rays of sunlight penetrate the lower atmosphere and warm the earth's surface. Fig. 5-5, p. 82

Animation Greenhouse effect interaction.

Major Greenhouse Gases • Water vapor: hydrologic cycle • Carbon dioxide (CO2):burning fossil fuels (coal), deforestation, change in CO2 levels correlate with a change in avg. global temperature • Methane (CH4):cattle, termites, landfill, coal production, natural gas leaks • Nitrous oxide (N2O): burning fossil fuels, fertilizer, livestock waste • CFCs, HFCs, Halons: AC, fridges, fire extinguishers, cleaning solvents, plastic foams • Table 16-1, p. 370

Table 16-1, p. 370

Atmospheric Carbon Dioxide and Global Temperatures 380 360 340 320 300 Concentration of carbon dioxide in the atmosphere (ppm) 280 Carbon dioxide 260 240 +2.5 220 0 200 Variation of temperature (˚C) from current level –2.5 180 –5.0 –7.5 Temperature change –10.0 End of last ice age 160 120 80 40 0 Fig. 16-4, p. 370 Thousands of years before present

Climate Change and Human Activities • In 1988, the UN and World Meteorological Organization established the Intergovernmental Panel on Climate change (IPCC) to project future climate changes. • Since 1861, and especially 1950, human emissions of greenhouse gases have greatly increased. This is due to deforestation, cars exhaust , and using inorganic fertilizer among others. • The US, with less than 5 percent of world population is the world’s largest emitter of CO2. • Troposphere warming • 20th century warmest in 1000 years • Average global temperatures rising about 1.5 degrees since 1861 • 16 warmest years since 1980 and 10 warmest years since 1990 • Glaciers and floating sea ice melting • Melting of Greenland’s Ice sheets will cause sea levels to rise around the world. • Melting permafrost and release of more greenhouse gases (Co2 and CH4) • Rising sea level (4-8 inches)

Increases in Average Atmospheric Carbon Dioxide Since 1860 410 360 Parts per million 310 260 1800 1900 2000 2100 Year Carbon dioxide (CO2) Fig. 16-5a, p. 371

Increases in Average Atmospheric Methane Since 1860 2.4 1.8 Parts per million 1.2 0.6 2000 1900 2100 1800 Year Methane (CH4) Fig. 16-5b, p. 371

Increases in Average Atmospheric Nitrous Oxide Since 1860 320 310 300 Parts per million 290 260 1900 2000 2100 1800 Year Nitrous oxide (N2O)

Shrinking Arctic Sea Ice (1979-2003) Fig. 16-6, p. 372

Scientific Consensus on Future Climate Change • Mathematical models • Model data and assumptions • Predictions of the models • Models indicate most recent warming due to human activities • Very likely Earth’s mean temperature will increase in 21st century

Processes that Determine Average Temperature and Greenhouse Gas Content Troposphere Cooling from increase CO2 removal by plants and soil organisms CO2 emissions from land cleaning, fires, and decay Warming from decrease Aerosols Heat and CO2 removal Heat and CO2 emissions Greenhouse gases Ice and snow cover Shallow ocean Land and soil biotoa Long-term storage Natural and human emissions Deep ocean Fig. 16-7, p. 372

Measured Average Temperatures and Future Predictions Fig. 16-8, p. 373

Concerns about a Warmer Earth • Droughts • Higher sea level and coastal flooding • Disrupted ecology • Economic and social costs • Abrupt changes • Severe storms • Insects and infectious diseases

Factors Affecting the Earth’s Temperature • Ability of oceans to store carbon dioxide • Local global cooling is possible • Effects of cloud cover • Jet contrails • Aerosols: volcanic eruptions and human activities • Sulfate and black carbon aerosols • Photosynthesis • Methane emissions: methane hydrates

Shallow and Deep Ocean Currents Fig. 16-9, p. 374

Agriculture Water Resources Forests • Changes in forest composition and locations • Disappearance of some forests, especially ones at high elevations • Increased fires from drying • Loss of wildlife habitat and species • Changes in water supply • Decreased water quality • Increased drought • Increased flooding • Snowpack reduction • Melting of mountaintop glaciers • Shifts in food-growing areas • Changes in crop yields • Increased irrigation demands • Increased pests, crop diseases, and weeds in warmer areas Biodiversity Sea Level and Coastal Areas • Rising sea levels • Flooding of low-lying islands and coastal cities • Flooding of coastal estuaries, wetlands, and coral reefs • Beach erosion • Disruption of coastal fisheries • Contamination of coastal aquifiers with salt water • Extinction of some plant and animal species • Loss of habitats • Disruption of aquatic life Weather Extremes Human Health • Decreased deaths from cold weather • Increased deaths from heat and disease • Disruption of food and water supplies • Spread of tropical diseases to temperate areas • Increased respiratory disease and pollen allergies • Increased water pollution from coastal flooding • Increased formation of photochemical smog Human Population • Prolonged heat waves and droughts • Increased flooding from more frequent, intense, and heavy rainfall in some areas • Increased deaths from heat and disruption of food supplies • More environmental refugees • Increased migration Benefits and Negative Impacts of Global Warming Fig. 16-10, p. 376

Possible Effects of Global Warming on Beech Trees Beech Future range Overlap Present range Fig. 16-11, p. 377

Why Climate Change is a Difficult Problem • Complex causes • Global problem: How can we all agree? • Long-term problem • Harmful and beneficial effects of climate change not spread evenly • Can’t stop climate change, only slow rate and adapt • Solutions are difficult and controversial

Options to Deal with Climate Change • “Wait and see” strategy: we need more research • “Act now” strategy • “Act now with no regrets” strategy

Solutions to Global Warming Solutions Global Warming Prevention Cleanup Cut fossil fuel use (especially coal) Remove CO2 from smokestack and vehicle emissions Shift from coal to natural gas Store (sequester) CO2 by planting trees Improve energy efficiency Shift to renewable energy resources Sequester CO2 deep underground Transfer energy efficiency and renewable energy technologies to developing countries Sequester CO2 in soil by using no-till cultivation and taking crop land out of production Reduce deforestation Sequester CO2 in the deep ocean Use more sustainable agriculture Repair leaky natural gas pipelines and facilities Limit urban sprawl Reduce poverty Use feeds that reduce CH4 emissions by belching cows Slow population growth Fig. 16-13, p. 379

Options to Deal with Climate Change “Wait and see” strategy – need more research to prove what the effects really will be “Act now” strategy – reduce any risks from global warming “Act now with no regrets” strategy – stop the threat of global warming immediately even if no risks appear to be of direct threat

Solutions to Global Warming Solutions Global Warming Prevention Cleanup Cut fossil fuel use (especially coal) Remove CO2 from smokestack and vehicle emissions Shift from coal to natural gas Store (sequester) CO2 by planting trees Improve energy efficiency Shift to renewable energy resources Sequester CO2 deep underground Transfer energy efficiency and renewable energy technologies to developing countries Sequester CO2 in soil by using no-till cultivation and taking crop land out of production Reduce deforestation Sequester CO2 in the deep ocean Use more sustainable agriculture Repair leaky natural gas pipelines and facilities Limit urban sprawl Reduce poverty Use feeds that reduce CH4 emissions by belching cows Slow population growth Fig. 16-13, p. 379

Removing Carbon Dioxide from the Atmosphere Tanker delivers CO2 from plant to rig Oil rig Coal power plant Tree plantation CO2 is pumped down from rig for deep ocean disposal Abandoned oil field Crop field Switchgrass CO2 is pumped down to reservoir through abandoned oil field Spent oil reservoir is used for CO2 deposit = CO2 deposit = CO2 pumping Fig. 16-14, p. 380

Government Roles in Reducing the Threat of Climate Change Funding for carbon dioxide removal technologies Carbon taxes or subsidies Energy taxes or subsidies Decreasing other taxes Leveling the economic playing field Technology transfer Kyoto Protocol What other countries, cities and businesses are doing

Basic Solutions Three basic solutions to reducing the threat of global warming: 1. Improve energy efficiency to reduce fossil fuel use. 2. Shift from carbon-based fossil fuels to carbon-free renewable energy sources. 3. Sequester and store as much CO2 in soil, vegetation, underground, and deep in the ocean

What Can You Do? What Can You Do? Reducing CO2 Emissions • Drive a fuel-efficient car, walk, bike, carpool, • and use mass transit • Use energy-efficient windows • Use energy-efficient appliances and lights • Heavily insulate your house and seal all drafts • Reduce garbage by recycling and reuse • Insulate hot water heater • Use compact fluorescent bulbs • Plant trees to shade your house during summer • Set water heater no higher than 49°C (120°F) • Wash laundry in warm or cold water • Use low-flow shower head Fig. 16-15, p. 382

Preparing for Climate Changes Develop crops that need less water Waste less water Connect wildlifereserves with corridors Move people away from low-lyingcoastal areas Stockpile 1- to 5-yearsupply of key foods Move hazardous material storagetanks away from coast Prohibit new constructionon low-lying coastal areasor build houses on stilts Expand existingwildlife reservestoward poles Fig. 16-16, p. 382

Ozone Depletion in the Stratosphere Ozone (O3) is found within the atmosphere and effectively traps 95% of the harmful UV radiation from the sun, as well as lock in the heat that is released from the earth Ozone depletion is greatest at the poles (positive feedback less ozone near the poles means more heat and more ice melting) Causes: chlorofluorocarbons (CFCs) and other chemicals CFCs destroy the ozone layer by breaking apart ozone molecules

Animation How CFCs destroy ozone animation

CFCs Former uses of CFCs: Coolants in air conditioners and refrigerators Propellants in aerosol cans Cleaning solutions for electronic parts Fumigants Bubbles in plastic packing foam Rowland and Molina’s research: Discovered that CFCs were lowering the avg. concentration of ozone in the stratosphere Called for an immediate ban on CFCs Four major conclusions: CFCs remain in the atmosphere b/c they are insoluble in water After 11-20 yrs CFCs rise into the stratosphere through air mixing Once in the atmosphere, CFCs are broken down by UV into their single elements which then break down ozone. Each CFC molecule can last in the stratosphere for 65-385 years, during which a single chlorine molecule can convert O3 to O2

Ozone Thinning Seasonal: The amount of ozone changes during the season In 1984 40-50% of the ozone over Antarctica disappeared during September and November. Consequences: Ozone depleted air flows to different parts of the world causing an increase of damaging UV-B levels by 3-10%, sometimes as high as 20% i.e. Australia

Consequences of Ozone Loss Natural Capital Degradation Effects of Ozone Depletion • Human Health • Worse sunburn • More eye cataracts • More skin cancers • Immune system suppression • Food and Forests • Reduced yields for some crops • Reduced seafood supplies from reduced phytoplankton • Decreased forest productivity for UV-sensitive tree species • Wildlife • Increased eye cataracts in some species • Decreased population of aquatic species sensitive to UV radiation • Reduced population of surface phytoplankton • Disrupted aquatic food webs from reduced phytoplankton • Air Pollution and Materials • Increased acid deposition • Increased photochemical smog • Degradation of outdoor paints and plastics • Global Warming • Accelerated warming because of decreased ocean uptake of CO2 from atmosphere by phytoplankton and CFCs acting as greenhouse gases Fig. 16-17, p. 384

Skin Cancers Ultraviolet A Ultraviolet B Thin layer of dead cells Hair Epidermis Squamous cells Basal layer Sweat gland Melanocyte cells Dermis Basal cell Blood vessels Squamous Cell Carcinoma Melanoma Basal Cell Carcinoma Fig. 16-18a, p. 385

Skin Cancers DO NOT POST TO INTERNET DO NOT POST TO INTERNET Squamous Cell Carcinoma Melanoma DO NOT POST TO INTERNET Basal Cell Carcinoma Fig. 16-18bcd, p. 385

Reducing Exposure to Ultraviolet Radiation What Can You Do? Reducing Exposure to UV-Radiation • Stay out of the sun, especially between 10 A.M. and 3 P.M. • Do not use tanning parlors or sunlamps. • When in the sun, wear protective clothing and sun– • glasses that protect against UV-A and UV-B radiation. • Be aware that overcast skies do not protect you. • Do not expose yourself to the sun if you are taking antibiotics or birth control pills. • Use a sunscreen with a protection factor of 15 or 25 if • you have light skin. • Examine your skin and scalp at least once a month for moles or warts that change in size, shape, or color or sores that keep oozing, bleeding, and crusting over. If you observe any of these signs, consult a doctor immediately. Fig. 16-19, p. 386

Protecting the Ozone Layer Allow for slow recovery of the ozone layer Montreal Protocol: 36 nations met to reduce CFC emissions by 35%, but did not include ODCs (ozone depleting chemicals). Copenhagen Protocol: 93 nations, made amends to Montreal Protocol to include phase-out of ODCs International cooperation: 177 nations have signed various agreements to cut CFCs and CDCs and have greatly reduced the levels and damage done to the ozone layer. It is estimated that in 2100 ozone levels should return to the levels seen back in 1950.

Climate Change and Ozone Loss