Atmosphere
Layers separated by temperature variations.
1. Troposphere: 0-12 km
-- where we live-- gets colder as you go up.-- all weather occurs here.-- all water vapor occurs here.
Atmosphere
2. Stratosphere: 12-50 km
-- ozone layer-- ozone absorbs short-wave (dangerous) radiation.-- temperature gets warmer as you go up.
Annual Maximum Ozone Hole
Atmosphere
3. Mesosphere: 50-80 km
-- gets cold again as you go up.-- air is very thin.
4. Thermosphere: 80-600 km
-- gets warmer as you go up.-- last layer
Greenhouse Effect
Atmosphere holds in heat radiated from Earth.
- keeps Earth warm for us.
Greenhouse Gas = chemical compound that allows short-wave radiation in,
but, absorbs outgoing long-wave radiation (infrared/heat).
Greenhouse Gases
1. Water vapor - most abundant (largest amount).
2. Carbon dioxide (CO2) - natural (plants) and man-made (oil and gas).
3. Methane (best absorber), CFCs (aerosol sprays…stay 100 years in atmosphere).
“Greenhouse effect” Increasing greenhouse gases trap more heat
Carbon Dioxide
Carbon Dioxide (CO2) levels historically precede and/or follow temperature rises.
How do we know?
Ice cores from Antarctica… 450,000 year record.
Natural CO2 Range
Devastating Evidence
Computer models
Aspen, CO Forecast:
Partly cloudy todayHigh : 28°FLow: 13°F
Increasing clouds over night. Colder tomorrow.
Why Should We Care?
Climate
Climate = characteristic weather of a region. Ex. 100 year pattern.
Major Elements:
TemperaturePrecipitation (Moisture)
Problems
Climate change = warmer, drier, wetter, more extreme weather.
3 to 7 feet rise in sea levels by end of century.
Arctic temperature rising faster than others.
Glacier melting = too much fresh water.
What Do Climate Scientists Think?