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Atmosphere Climate Ozone

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Presentation on theme: "Atmosphere Climate Ozone"— Presentation transcript:

1 Atmosphere Climate Ozone
Chapter 20 Atmosphere Climate Ozone

2 Layers of the Atmosphere
Troposphere (lowest layer) Tropopause Stratosphere Stratopause Mesosphere Mesopause Thermosphere (highest km)

3 Composition of the troposphere
Less than 2% H2O vapor (.01%-4%) Argon gas (1%) CO2 (0.04%) Trace gases

4 Structure & Temp of Atmosphere
Look at Fig and Table 20-1 Troposphere = lowest layer; tropics  10 miles (16km); higher altitudes  5 miles (8km) Water vapor & clouds Greenhouse gases Colder w/ altitude (generally) Pollutants reach top w/in a few days

5 Structure & Temp of Atmosphere cont.
Tropopause ---- separate Troposphere from stratosphere Stratosphere - temp increases w/ altitude  40 miles - contains the ozone shield - Ozone absorbs UV radiation from the sun & filters the rays - No precipitation

6 Global warming The greenhouse effect is natural and important to keep the earth warm enough for life to exist Global warming occurs when humans contribute too much of these greenhouse gases leading to a small (1-3 degree C) but significant rise in the global average temperature. Analogy – Car on a sunny day


8 Build up of Greenhouse gases:
CO2 Fossil Fuel use Deforestation

9 Methane (CH4) Microbial fermentation (Landfill) Coal and oil deposits
Natural gas pipelines Cows (manure) Methane is the second most important green house gas (next to CO2)

10 Nitrous Oxides Biomass burning Chemical fertilizers
Fossil Fuel Burning

11 CFC-Chlorofluorocarbons
Refrigerants Solvents Pesticides Aerosols (Old)

12 Ozone (O3) Tropospheric ozone is BAD
If we breath it, it causes lung damage It is also a greenhouse gas Stratospheric ozone is GOOD It shields us from the harmful UVB rays of the sun. Ozone depletion is the thinning of the stratospheric ozone shield (mostly over the South Pole) Analogy – Stratospheric O3 is like sunscreen for the earth.

13 The Making of Ozone O2 + UVB (280 – 320 nm more energetic) O + O
The free O bonds to existing O2 (O + O2) Ozone is made (O3) O2 + UVB  O + O ; O + O2  O3


15 The Destruction of Ozone
CFC – chlorofluorocarbons Cl – FC (UV rays breaks bond) The free Cl “attacks ozone” O3 + Cl  O2 + (Cl – O) Cl – O is unstable so the bond will break and the Cl will “attack” another ozone molecule


17 Greenhouse Effect Troposphere Traps heat near the Earth’s surface Water vapor, carbon dioxide, methane Globing warming Ozone shield Stratosphere filters UV radiation Oxygen gas, Ozone gas Ozone depletion  more UV  cancer Where? What Happens? Which gases? Problem?

18 The End

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