Presentation is loading. Please wait.

Presentation is loading. Please wait.

Atmospheric and Climate Change

Similar presentations

Presentation on theme: "Atmospheric and Climate Change"— Presentation transcript:

1 Atmospheric and Climate Change
Chapter 13

2 13-1 Climate and Climate Change
Objectives 1. Explain the difference between weather and climate. 2. Identify four factors that determine climate. 3. Explain why different parts of the earth have different climates. 4. Explain what causes the seasons.

3 What Factors determine climate?
Climate-long term prevailing weather (state of the atmosphere) Determined by: Latitude, atmospheric conditions, circulation patterns, oceanic patterns, local geography, solar activity, and volcanic activity.

4 Latitude Amount of solar energy that reaches the surface

5 Atmospheric circulation
Warm air rises, cold air sinks Warm air holds more moisture Heat differences cause winds

6 Global Circulation Patterns
Patterns are disrupted at the equator Cool air rises at the equator and is forced to the poles Air condenses and 30 degrees N and S Air sinks, causes water to evaporate from land Flows back to the poles or equator

7 Prevailing winds (westerlies)
Blow from one direction most of the year Trade winds at 30 degrees N and S

8 Ocean Circulation patterns
Hold vast amounts of heat Currents redistribute heat Cold and warm currents

9 El Nino – Southern Oscillation
Short-term periodic change in the location of warm and cold currents in the Pacific ocean Winds in west Pacific become stronger and push warm water eastward Causes drought in Indonesia and Australia

10 Pacific Decadal oscillation
La Nina - Water in the Pacific is colder than usual Pacific Decadal oscillation Long term change in currents


12 Local geography Mountain ranges Seasonal changes

13 Solar activity Increase UV and energy from the sun

14 Volcanic activity Releases gases (SO2)and dust into the atmosphere which affects weather

15 13-2 Ozone Shield Objectives
1. Explain how the ozone layer shields the Earth from much of the sun’s harmful radiation. 2. Explain how chlorofluorocarbons damage the ozone layer. 3. Explain the process by which the ozone hole forms. 4. Describe the damaging effects of ultraviolet radiation. 5. Explain why the threat to the ozone layer is still continuing today.

16 Ozone layer – ozone is concentrated
Ozone Shield Ozone layer – ozone is concentrated O3 Absorbs UV – protects DNA of all living things

17 Chemicals that cause Ozone depletion
CFC’s (chlorofluorocarbons) damages ozone Stable at surface but reacts in atmosphere destroys ozone molecules

18 Ozone hole Thinning of atmospheric ozone that occurs at the poles
First report in 1985, but noticed in 1970’s

19 Chlorine reacts with ozone and destroys it
Form in polar stratospheric clouds Can’t be replaced by ground level ozone

20 Affects Increased UV radiation Damages DNA Cancer Weaker immune system

21 Kills phytoplankton Harms amphibians, marine life, and plants

22 International agreements (Montreal Protocol) to eliminate CFC use
Protection of Ozone International agreements (Montreal Protocol) to eliminate CFC use US pledged to ban all substances by 200 Did we do it?? Level is going down

23 It will be years before affects of programs can be measured because CFCs stay active for years

24 13-3 Global Warming Objectives
1. Explain why Earth’s atmosphere is like the glass in a greenhouse. 2. Explain why carbon dioxide in the atmosphere appears to be increasing. 3. Explain why many scientists think that the Earth’s climate may be becoming increasingly warmer. 4. Describe what a warmer Earth might be like.

25 Greenhouse affect Traps sun energy
Major greenhouse gases (absorb and radiate heat): Water vapor, CO2, CFCs, methane, and nitrous oxides


27 Keeling Started measuring CO2 levels 1958 – 314 ppm 2000 – 368 ppm Increased use of fossil fuels Levels have normal seasonal fluctuations

28 Glaciers and poles melt
Increase of CO2 could cause a global rise in temperature (global warming) Glaciers and poles melt Sea level rise

29 Affects Increase of global temperature Rise of sea level Loss of coastline Agriculture Droughts or too much rain

30 Some scientists believe that the warming is part of natural climatic variability
What is the evidence?

31 Consequences of a Warmer Earth
These things could happen rather caused by nature or man…. Melting of ice and sea level rise Global weather patterns change Human health problems Agriculture Plants and animals

32 How do we reduce the risk?
Reforestation Reduce dependence of on fossil fuels Reduce use of harmful chemicals International agreements - Kyoto Protocol


Download ppt "Atmospheric and Climate Change"

Similar presentations

Ads by Google