GLOBAL CLIMATE

1. GLOBAL CLIMATE WHAT ARE THE CAUSES AND EFFECTS OF HURRICANES AND TORNADOES? HOW CAN YOU IDENTIFY GLOBAL PATTERNS OF CLIMATE? WHAT FACTORS CAUSE GLOBAL CLIMATE PATTERNS?

2. GLOBAL CLIMATE • GLOBAL WARMING – the gradual increase in the temperature of the earth’s surface. • Solar radiation – energy from the sun • Greenhouse effect – the heating of the earth’s surface caused by gases creating a ‘roof’ over the lower atmosphere

3. GLOBAL WARMING: WHAT’S THE PROBLEM • During the day, earth’s atmosphere protects the planet from the full strength of the sun’s heat energy. • At night, when half the earth is in shadow, the atmosphere keeps that heat energy from escaping into space. • This means our atmosphere helps to cool down daytime temperatures and maintain the temperature at night. But, there is a problem.

4. PROBLEM • For the past two centuries the atmosphere has been capturing more solar energy, causing a slow increase in temperature on the earth’s surface, known as GLOBAL WARMING. • The sun isn’t burning brighter or hotter. So, where is the extra heat coming from? • What effects will this have on the planet if it continues?

5. GREENHOUSE GASES

6. GREENHOUSE GASES • Gases are made up of tiny particles called molecules that absorb the sun’s heat energy. • The name ‘greenhouse gases’ comes from the way gases such as carbon dioxide (CO2) and nitrous oxide (NO2) capture solar radiation. • They act somewhat like a “roof” on the lower atmosphere, like the glass roof of a gardener’s greenhouse. • This is called the ‘greenhouse effect.

7. 2 DIAGRAMS – SHOWING THE GREENHOUSE EFFECT

8. GREENHOUSE GASES • There are many similarities in the two diagrams (greenhouse gases and gardener’s greenhouse). • First, the sunlight reaches the earth as short-wave radiation, which can penetrate both the greenhouse roof and the greenhouse gases of the atmosphere. (that’s why you get a sunburn on a cloudy day). • Next, the greenhouse floor and the earth’s surface warm up and give off heat as long – wave radiation. • Notice how these longer waves cannot pass back through the greenhouse glass of the greenhouse gases. • This causes temperatures to rise both in the greenhouse and in the earth’s lower atmosphere.

9. EFFECTS OF RISING TEMPERATURE • GLOBAL WARMING IS CAUSING MAJOR CHANGES IN THE SURFACE OF THE EARTH – THEY INCLUDE • Temperature increase of 8C in Arctic regions, causing melting of the polar ice. • Melting glaciers in mountain areas because of hotter summers and less winter snow • More ocean icebergs as the Antarctic ice shelf and Greenland glaciers break up. • Rising sea levels around the world as frozen water is released into the ocean • More unpredictable weather as the sun raises ocean temperatures in the tropics • Rapid changes in natural vegetation patterns and in wildlife habitats, such as that of the polar bear.

10. THINKING IT OVER • Answer these questions in your book • Why is the atmosphere so important to life on earth? Why are temperatures in the lower atmosphere rising? • Think of different examples to show how each of the six effects of global warming can affect plants, animals, or humans.