1. Ch. 13 Atmosphere and Climate Change

2. Weather and Climate
Weather is the state of the atmosphere at a particular place at a particular moment
(This morning I watched the weather to see if I needed a coat)
Climate is the long-term average of weather conditions for a particular area ( The climate in Georgia includes all 4 seasons and is relatively mild)

3. Factors that determine climate
latitude (most important)
Atmospheric circulation patterns
Oceanic circulation patterns
Local geography
Solar activity
Volcanic activity

4. Latitude
The distance north or south of the equator in horizontal lines, measured in degrees.
The equator is located at 0° latitude.
More solar energy falls on areas near the equator, less on areas closer to poles
Near equator, temps are high all year; no winters
Near poles, less sun, colder temps

5. Atmospheric circulation
Cold air sinks
Hot air rises
Warm air holds more moisture than cold air
Areas near equator usually get more rain
Movement of air= wind
Earth rotates causing atmospheric circulation

6. Oceanic circulation patterns
Movement of ocean currents is caused by wind and rotation of Earth
El Nino -short term change in location of warm and cold water masses in Pacific; ↑rainfall in Southern US, drought in Indonesia and Australia
La Nina -cooler water temps in Pacific; causes opposite of El Nino

7. Topography Mountains affect precipitation
Air moves from oceans to mountains; as air rises, it cools and rain occurs
As air moves over the mountains, the air becomes drier and warmer
↑altitude=↓temps

8. Sun and volcanic eruptions
Solar maximum-↑ amounts of UV radiation
From sun ↑temps on Earth
Volcanic eruptions produce extra gases into atmosphere which causes a haze; this can lead to ↓ temps

9. Seasonal changes
Seasons are caused by the tilt of the Earth as it rotates
Affects the intensity of sunlight on Earth’s surface
During the summer(US) we are tilted more towards the sun
During the winter(US) we are tilted away from the sun

10. Ozone Shield
The ozone layer is an area in the stratosphere where ozone is highly concentrated. Ozone =O3
Ozone layer absorbs most of UV radiation from the sun
Ozone is our sunscreen

11. Ozone Layer

12. During 1970s, scientists worried that chemicals called CFCs(chlorofluorocarbons)
Might be damaging the ozone layer. You find CFCs in coolants used in refrigerators & air conditioning units. Also in deodorants, hair sprays and paints.
When CFCs break down they destroy ozone.

13. In 1985, scientists revealed research that showed a large hole in the ozone layer over South Pole.

14. As ozone disappears, UV radiation ↑ on earth.
This leads to more skin cancer.
May also kill phytoplankton and kill eggs of amphibians.
Developed countries agreed to eliminate CFCs by 1995.

15. Section 3
Global Warming

16. Global Warming
Heat energy does not pass through glass as easily as light energy does.
Sunlight comes into atmosphere but the heat it produces gets trapped near Earth’s surface.
This process of heat absorption is called the greenhouse effect.

17. Water vapor and Carbon dioxide account for most of the greenhouse gases and absorption of heat in the atmosphere
CO2 is taken out of air by plants…in winter when many plants die, CO2 levels rise
Scientists believe global warming may alter climate and melt glaciers. This may ↑ sea levels and change salinity(saltiness) of oceans.
This could change ocean currents and thus further change weather patterns(ie Day after Tomorrow)

18. Kyoto Protocol Treaty developed in 1997 by 160 countries.
Requires developed countries to ↓emissions of CO2 and greenhouse gases by 5%.
The US decided NOT to ratify the Kyoto Protocol in 2001.