APES 9.1-9.5

stratospheric ozone benefits

• blocks sun’s radiation (UV-A, B, C)

• UV: increases skin cancer and cataract risks; also harmful to plant cells and decreases ability to photosynthesize

CFCs (chlorofluorocarbons)

lead to breakdowns

→ aerosol spray cans/styrofoam/refrigerants

Montreal Protocol on Substances that Deplete the Ozone Layer

ozone depletion solution

• committment to decrease CFC production by 50% by 2000\

• 180 countries eventually signed

• addressed 96 ozone-depleting compounds

climate change

changes in average weather that occurs in an area over a period of years to decades

natural climate change

el nino/el nina

anthropogenic climate change

fossil fuel combustion

global warming

warming of the oceans, land masses, and atmosphere of Earth (specific aspects of climate change)

Effects of Global Climate Change

• Earth naturally undergoes major shifts of temperatures (recorded by CO2 data and ice cores)

• Climate change (warming) effects:

  • rising temperatures

  • melting permafrost and sea ice

  • rising sea levels

  • displacement of coastal populations

greenhouse effect

gases that absorb infrared radiation

N2 and O2

most common gases inn atmosphere

gases that cause the greenhouse effect

water vapor, carbon dioxide, methane, nitrous oxide, ozone, and chlorofluorocarbons

burning fossil fuels

-we put out more fossil fuel carbon than gets created

-long time to convert OM back to fossil fuels

-each fossil fuel produces different amount of CO2

-PM from combustion of fossil fuels can also play a role in global warming

agricultural practices

-flooded fields produce methane and nitrous oxide

-synthetic fertilizers, manures, & crops can create an excess of nitrogen → nitrous oxide

-livestock produces methane and naure produces CO2

sources of greenhouse gases

burning fossil fuels, agricultural practices, deforestation, landfills, and industrial production of GHG

deforestation

mass of carbon that made up the trees is added to the atmosphere by combustion or decomposition

landfills

household waste slowly decomposes and produces CO2 or methane if under poorly aerated conditions

CFCs

banned now due to Montreal Protocol, but are a potent GHG

*stratospheric ozone loss does not contribute to climate change; but CFCs in the atmosphere do

ocean and vegetation

excess CO2 was originally thought to just be taken up by ________

Mauna Loa Observatory

CO2 impacts discovered

CO2 level vary seasonally (fall vs. spring)

CO2 concentrations do increase from year to year

polar ice

consequences of global climate change

decrease amount of ice coverage and thickness in Artic and Greenland

Antartica shows a small increase in area but loss in thickness → overall ice mass reduction

warming 1-4C and expected to warm an additional 4-7C over next 70 years