Chapter Thirteen: Atmosphere and Climate Change

Section One: Climate and Climate Change What Factors Determine Climate? Climate: the long-term prevailing weather conditions at a particular place bases upon records taken Things that determine climate Latitude Atmospheric circulation patterns Oceanic circulation patterns Topography Solar and volcanic activity

Section One: Climate and Climate Change Latitude The distance from the equator measured in degrees north or south of the equator Equator is at 0˚ latitude North Pole is at 90˚ latitude north South Pole is at 90˚ latitude south Low latitudes: closer to the equator and receive more sunlight High latitudes: closer to the poles and receive less sunlight

Section One: Climate and Climate Change

Section One: Climate and Climate Change Atmospheric Circulation How the air moves across the earth Cold air sinks because it is denser than warm air ( compresses and warms as it sinks) Warm air rises (expands and cools as it rises) Warm air holds more water vapor than cold air (causes fog, rain and snow)

Section One: Climate and Climate Change Atmospheric Circulation The sun warms the ground and warms the air above the ground Warm air rises, and cooler air replaces it (wind) Areas that get more sunlight have more warm air that rises and cools. When it cools it can hold less water vapor so precipitation occurs. Therefore, the more sunlight an area receives, the more precipitation it gets.

Section One: Climate and Climate Change Atmospheric Circulation Prevailing Winds: winds that blow predominately in one direction throughout the year To the right of the Northern Hemisphere, or to the left of the Southern Hemisphere

Section One: Climate and Climate Change Oceanic Circulation Patterns Water holds a large amount of heat Ocean current movement mostly caused by wind El Niño: the short term periodic change in the location of warm and cold water masses in the Pacific Ocean Warm water is pushed eastward, and rainfall follows More rainfall in southern U.S. and South America La Niña: the water in the eastern Pacific Ocean is cooler than usual

Section One: Climate and Climate Change

Section One: Climate and Climate Change Topography Topography: local geography of the area Mountains and mountain ranges influence precipitation and temperature

Section One: Climate and Climate Change Solar and Volcanic Activity Sun Emits UV radiation which produces more ozone More ozone causes the earth to also warm Volcanoes Causes sulfur dioxide to be released Sulfur dioxide mixes with water vapor to make haze Haze reflects sunlight and causes a global temperature decrease

Section One: Climate and Climate Change Seasonal Changes in Climate Seasons are a result of the tilt of the Earth’s axis Causes a change in the amount of sunlight received

Section Two: The Ozone Shield Ozone Layer Ozone Layer: an area in the stratosphere where ozone is highly concentrated Chemicals that cause Ozone Depletion CFCs: human made chemicals that destroy ozone molecules Also causes a problem in the bird population

Section Two: The Ozone Shield The Ozone Hole Ozone Hole: a thinning of stratospheric ozone that occurs over the poles during the spring

Section Two: The Ozone Shield The Ozone Hole Polar Stratospheric Clouds: high altitude clouds made of water and nitric acid Where CFCs are converted to chlorine Chlorines are broken apart by UV Chlorines destroy the ozone

Section Two: The Ozone Shield The Ozone Hole Effects on Humans, Animals, and Plants More UV radiation can pass through the atmosphere UV damages DNA and can cause skin cancer Kills phytoplankton Kills amphibian eggs Interfering with photosynthesis

Section Two: The Ozone Shield Protecting the Ozone Layer Montreal Protocol: nations agreed to limit their production of CFCs United States pledged to ban all substances that harm the ozone by 2000

Section Three: Global Warming The Greenhouse Effect Greenhouse Effect: caused by atmospheric gases radiating and not absorbing hear causing the gradual warming of the Earth Greenhouse gases Water Vapor Carbon Dioxide CFCs Methane Nitrous Oxide

Section Three: Global Warming The Greenhouse Effect Carbon dioxide level decrease in the summer and increase in the winter Photosynthesis removes carbon dioxide from the atmosphere Carbon dioxide levels are steadily rising

Section Three: Global Warming Global Warming: the increase in the average temperature at Earth’s surface

Section Three: Global Warming Consequences of a Warmer Earth Melting Ice and Rising Sea levels Global Weather Patterns Change Human Health Problems Droughts Killing Crops Shifts Geographical Ranges of Plants and Animals

Section Three: Global Warming Recent Findings Temperature has increase 0.6˚C Snow cover and ice have decreased Average global sea level has risen Reducing the Risk Kyoto Protocol: required developed countries to decrease emissions of carbon dioxide and other greenhouse gases by an average of 5% below their 1990 levels by 2012