Global Change Unit Chapter 9: Sustaining Biodiversity: The Species Approach Chapter 19: Climate...
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Transcript of Global Change Unit Chapter 9: Sustaining Biodiversity: The Species Approach Chapter 19: Climate...
Global Change Unit
Chapter 9: Sustaining Biodiversity: The Species Approach
Chapter 19: Climate Change and Ozone Completion
Chapter 9: Sustaining Biodiversity - The Species
Approach
Extinction
Background extinction - Continuous low level extinction
Extinction rate - number of species that go extinct during a time period (%)
Extinction is natural, but human activities are destroying and degrading biodiversity causing premature extinctions.
Endangered and Threatened Species
Endangered species have so few survivors that the species could soon become extinct.
Threatened species are abundant in their natural range but could become endangered because of declining numbers.
Endangered
Species
Why prevent extinction?Instrumental value - usefulness to us in
providing ecological and economic services.
Intrinsic or existence value - species have the right to exist.
HIPPCO: The greatest threat to species
H: Habitat destruction, degradation and fragmentation
I: invasive speciesP: population and resource useP: pollutionC: climate changeO: overexploitation
Invasive Species
Accidentally or intentionally introduced
Often have no natural predators or competitors.
Invasive Species
Prevention of new invasive species is important.
Overexploitation
Illegal killing, capturing and selling of wild species.
Demand for bushmeatExotic pets
Protecting Species
U.S. Endangered Species Act - Identify and protect endangered species in the U.S. and abroad. Based on biological factors alone, which makes it controversial.
ESA forbids projects that could jeopardize and endangered species or threaten its habitat.
Protecting Species
Establish wildlife refuges and other protected areas.
Gene banks, botanical gardens, and wildlife farms
Zoos and Aquariums
Chapter 19: Climate Change and Ozone Depletion
The History of Global WarmingOver earth’s 4.5 billion year history its
climate has been altered by volcanic eruptions, solar input, moving continents, meteors etc.
Glacial and interglacial periods have marked the past 900,000 years.
Global Temperature
The Greenhouse Effect
The greenhouse effect warms the lower atmosphere in the surface of the earth.
How? Water vapor, carbon dioxide, methane and nitrous oxide (all make up 1%) molecules kinetic energy increases when energy is reflected by the earth into the atmosphere. The energy is then reflected back to the surface in the form of infrared energy.
Greenhouse Gases
Humans emit A LOT of greenhouse gases into the atmosphere.AgricultureDeforestationBurning fossil fuels
In the past, increases in greenhouse gases have coincided
with increased
global temperature.
Greenhouse GasesCO2 levels have increased from 228 ppb to 384
ppb (59%) in the last 275 years from mostly burning fossil fuels.
Methane emissions are caused by: dams, landfills, farm animals, extracting fossil fuels, melting permafrost.
N2O levels have risen by 20% during the last 275 years mostly due to increased use of nitrogen fertilizers.
Predicting the Effects of Global Warming is Complicated
Understanding Global Warming
Hotter Sun? Probably not, as the stratosphere has been cooling.
Oceans absorb carbon dioxide, but as they warm, they cannot hold as much and release CO2 back into the atmosphere (oops).
Understanding Global Warming
Increased Cloud Cover could reflect the sun and cool the earth or keep the energy near the surface (like a greenhouse gas). Depends on cloud type.
Air pollution - aerosols (suspended microscopic droplets and particles) can hinder or increase cloud formation.
Effects of Global Warming
Problem: The change in global temperature is occurring rapidly.
Effects of Global Warming
Ice and Snow Are Melting
Sea Levels are Rising
Permafrost is Melting
There is More
Changing Ocean Currents
Extreme weather in some areas
Biological ranges are being altered and biodiversity threatened.
Threats to Human Health
Global Warming and Biodiversity
Slowing Climate Change
Problems:Global IssueEffects are long lastingLong-term political issueImpacts of Climate Change are not spread
evenlySolutions could disrupt economies
Slowing Climate Change
Improve energy efficiencyShift from non-renewable fossil fuels to
a mix of renewable sources.Stop cutting forests (especially tropical)Capture and store as much CO2 as
possible.
How can this be done?
Slowing Climate Change
Carbon Capture and Storage
CCS involves removing CO2 from smokestacks and storing the elsewhere like abandoned coal beds or gas fields.Expensive power plantsHow can CO2 be captured
Requires a lot of energySupports continued use of coal
Governments and Climate Change
The cost of damages from global warming and the cost to slow it down are debatable.
Governments can regulate CO2 and CH4 pollutants, use carbon or energy taxes instead of property or income tax.
The Kyoto Protocol
In 1997, 161 nations met in Japan to negotiate a treaty to slow climate change.
174 of the worlds 194 nations ratified the treaty that required developed countries to reduce greenhouse gas emissions.
Allows for trading of greenhouse gas emissions. (caps set high)
Some are Making a Change
China and India are investing in sustainable development.
U.S. Companies are reducing greenhouse emissions to save money.Wal-Mart saves $34 million a year by
using cfl’s and auxiliary power units for shipping trucks.
Ozone Depletion
Seasonal thinning of the ozone layer caused by: Chlorofluorocarbons - air conditioners,
fridges, aerosol cans, cleaners, fumigantsHydrobromoflurocarbons - fire extinguishersMethyl bromide - fumigantHydrogen chloride - space shuttlesVarious chemicals from cleaning solvents
Ozone Depletion is Bad
More UV-A and UV-B radiation will reach the earth’s surface resulting in more cataracts, sunburns and skin cancer.
Increased radiation could impair or destroy phytoplankton.
Reversing Ozone DepletionStop producing all ozone-depleting
chemicals. (60 years to recover)
Warming the troposphere makes the stratosphere cooler which slows down ozone repair.
Copenhagen Protocol (1992) - 191 countries agreed to phase-out key ozone-depleting chemicals.