Presentation on theme: "Chapter 21: Climate Change Global Change Unit. Past climates Global cooling and warming occur in cycles Glacial and interglacial periods Glacial periods."— Presentation transcript:
Chapter 21: Climate Change Global Change Unit
Past climates Global cooling and warming occur in cycles Glacial and interglacial periods Glacial periods last about 100,000 years. Interglacial last about 10,000-12,500 years. Our current interglacial age has lasted about 12,000 years…
Average temperature over past 900,000 years Thousands of years ago Average surface temperature (°C) Present Glacial and Interglacial Periods
Temperature change over past 22,000 years Years ago Temperature change (°C) 20,00010,0002,0001, Now End of last ice age Agriculture established Average temperature over past 10,000 years = 15°C (59°F) Past 22,000 years
Temperature change over past 1,000 years Year Temperature change (°C) Past 1,000 years
Average temperature over past 130 years Year Average surface temperature (°C) Past 130 years
Ice can tell us WHAT? Past climate information is found through ice cores from Antarctica and Greenland. The ice core (see fig 21.3) can tell us: –Greenhouse gas concentrations –Solar activity –Snowfall –Forest fires (layers of soot) Core samples from lakes/ponds bottom tell us: –Pollen –Fossils –Plant life –Growth trends
Too much information!! What we do with all that information: IPCC: Intergovernmental Panel on Climate Change –2,000 experts from 70 nations IPCC uses probability to describe trends: –Virtually certain: more than 99% probability –Very likely: 90-99% probability –Likely: 66-90% probability Our current interglacial age is likely to last another 15,000 years
Pink vs. Blue
Whats happening here?
Greenhouse Effect Heat is trapped inside the atmosphere much like heat is trapped in a greenhouse. What causes the trapping? –Carbon Dioxide –Methane –NOx –CFCs –HCFCs –Halons –Water vapor (hasnt changed – closed system) –CF 4 This animation shows how a carbon dioxide molecule vibrates when it absorbs heat.
Greenhouse Effect Heat is trapped inside the atmosphere much like heat is trapped in a greenhouse. What causes the trapping –Carbon Dioxide –Methane –NOx –CFCs –HCFCs view clip view clip –Halons –Water vapor (hasnt changed – closed system) –CF 4
Effects to think about Increased death from heat, malnutrition Very likely (90-99%) that tree deaths from disease and pests will increase Very likely that wildfires will increase Loss of animals and plants that cant migrate quickly enough Increase in pest (high tolerance) animals and insects Tree species would move toward polar regions (5 miles per decade now) Increased hurricanes (over warmer water)
Carbon dioxide Temperature change End of last ice age Thousands of years before present Concentration of carbon dioxide in the atmosphere (ppm) –10.0 –7.5 –5.0 – Variation of temperature (˚C) from current level CO 2 effects
Wheres all this gas from? Burning of fossil fuels (CO 2 ) Deforestation (CO 2 ) Clearing and burning grasslands (CO 2 ) Larger cattle herds (CH 4 ) Rice paddies/fertilizers (No x and CH 4 ) Automobiles (1 gallon of gas = 20 lbs. of CO 2 ; one tank of gas = 360 lbs. of CO 2 )
Dirty, Rotten Americans! #1 producer of CO 2 emissions (24% of worlds emissions) CO 2 emissions from our cars is more than the emissions of everything that powers Japan! Each American produces more CO 2 than any other nations individuals (per capita). 500 tons of CO 2 in your lifetime! Huge amounts of methane from landfills and livestock.
The graphs say it all
Carbon dioxide (CO 2 ) Year Parts per million
Methane (CH 4 ) Year Parts per million
Year Parts per million Nitrous oxide (N 2 O)
Global Warming vs Climate Change Global warming: trend towards increasing temperatures. 10 warmest years on record have occurred since Global climate change: changes in precipitation, temperatures, storm intensity. Global warming can lead to global climate change.
Wheres the proof baby?
Proof of Global Warming 20 th century was hottest on record Since 1861, average global temperature has risen between 1 o o F (most of that has been since 1980) 16 hottest years on record have been since 1980, 10 hottest have been since Glaciers and sea ice are shrinking. Sea level rising (4 to 8 inches)
Arctic Sea Ice Changes
Factors Affecting Earths Temperature Oceans can store heat and CO 2, but no one knows how much. Cloud cover: can warm by trapping and releasing heat or cool by reflecting heat back to space (albedo effect)!
Albedo is measured on a scale from 0-1(or sometimes as a %). Very dark colors have an albedo close to 0 (or close to 0%). Very light colors have an albedo close to 1 (or close to 100%).
Albedo is measured on a scale from 0-1(or sometimes as a %). Forests have low albedo, near Snow and ice, have very high albedo, as high as 0.8 or 0.9, and reflect most of the solar energy that gets to them, absorbing very littleSnowice
Factors Affecting Earths Temperature Oceans can store heat and CO 2, but no one knows how much. Cloud cover: can warm by trapping and releasing heat or cool by reflecting heat back to space (albedo effect)! Outdoor air pollution: aerosols can either warm or cool the atmosphere (much like clouds) Stimulate photosynthesis: more CO 2 can temporarily cause higher photosynthesis. Temporary because plants will level off and die, releasing their CO 2 Methane trapped under ice is released when the ice melts.
Global Warming Solutions PreventionCleanup Cut fossil fuel use (especially coal) Shift from coal to natural gas Improve energy efficiency Shift to renewable energy resources Transfer energy efficiency and renewable energy technologies to developing countries Reduce deforestation Use more sustainable agriculture Slow population growth Store (sequester) CO 2 by planting trees Sequester CO 2 deep underground Sequester CO 2 in the deep ocean Repair leaky natural gas pipelines and facilities Use feeds that reduce CH 4 emissions by belching cows Remove CO 2 from smokestack and vehicle emissions
What are things would you be willing to do around your house?
Reducing CO 2 Emissions What Can You Do? 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
Is this a Review of the Air Pollution Chapter?
Ozone Depletion The culprits: –CFCs: used as coolants (Freon). Are now being phased out. –Halons: in fire extinguishers –Hydrobromofluorocarbons The hole: –More of a thinning. –August-November (late winter/spring) over Antarctica –Why: wind patterns bring pollutants up and polar vortex keeps them there.
Ultraviolet light hits a chlorofluorocarbon (CFC) molecule, such as CFCl 3, breaking off a chlorine atom and leaving CFCl 2. UV radiation Sun Once free, the chlorine atom is off to attack another ozone molecule and begin the cycle again. A free oxygen atom pulls the oxygen atom off the chlorine monoxide molecule to form O 2. The chlorine atom and the oxygen atom join to form a chlorine monoxide molecule (ClO). The chlorine atom attacks an ozone (O 3 ) molecule, pulling an oxygen atom off it and leaving an oxygen molecule (O 2 ). Cl C F O O O O O O O O O O Summary of Reactions CCl 3 F + UV Cl + CCl 2 F Cl + O 3 ClO + O 2 Cl + O Cl + O 2 Repeated many times
Spring Ozone Measurements Year Total ozone (Dobson units) October monthly means
Effects of Ozone Depletion Natural Capital Degradation 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
Kyoto Protocol: 1997; Reduce greenhouse gases. (concern is global warming) Montreal Protocol: 1987; Reduce use of CFCs (concern is ozone depletion) Copenhagen Protocol: 1992; Reduce ozone depleting chemicals (concern is ozone depletion)
Kyoto Protocol International agreement nations Directs 39 countries to take steps to decrease greenhouse gas emissions. Developing countries were not held to the same standards as developed ones. 2001: G.W. Bush withdrew the US from the agreement because of expense and the fact that developing countries like China and India werent held accountable.