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?