Presentation on theme: "Global Change Unit Chapter 9: Sustaining Biodiversity: The Species Approach Chapter 19: Climate Change and Ozone Completion."— Presentation transcript:
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.
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 bushmeat Exotic 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
The History of Global Warming Over earths 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.
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. Agriculture Deforestation Burning fossil fuels
In the past, increases in greenhouse gases have coincided with increased global temperature.
Greenhouse Gases CO 2 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. N 2 O 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 CO 2 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.
Slowing Climate Change Problems: Global Issue Effects are long lasting Long-term political issue Impacts of Climate Change are not spread evenly Solutions could disrupt economies
Slowing Climate Change Improve energy efficiency Shift from non-renewable fossil fuels to a mix of renewable sources. Stop cutting forests (especially tropical) Capture and store as much CO 2 as possible. How can this be done?
Carbon Capture and Storage CCS involves removing CO 2 from smokestacks and storing the elsewhere like abandoned coal beds or gas fields. Expensive power plants How can CO 2 be captured Requires a lot of energy Supports 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 CO 2 and CH 4 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 cfls and auxiliary power units for shipping trucks.
Ozone Depletion Seasonal thinning of the ozone layer caused by: Chlorofluorocarbons - air conditioners, fridges, aerosol cans, cleaners, fumigants Hydrobromoflurocarbons - fire extinguishers Methyl bromide - fumigant Hydrogen chloride - space shuttles Various chemicals from cleaning solvents
Ozone Depletion is Bad More UV-A and UV-B radiation will reach the earths surface resulting in more cataracts, sunburns and skin cancer. Increased radiation could impair or destroy phytoplankton.
Reversing Ozone Depletion Stop 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.