April 29, 2013
Chapter 18 Questions
Global Climate Change
1. What happens to solar radiation after it reaches Earth? How do greenhouse gases warm the lower atmosphere? 2. Solar radiation gets absorbed by the Earth's surface when it reaches Earth. This emits infrared radiation into the land, ice and water. Greenhouse gases warm the lower atmosphere because they re-emit infrared radiation in all directions that travels back downward warming the lower atmosphere. This has led to the phenomenon as the Greenhouse Effect. 1. Why is carbon dioxide considered the main greenhouse gas? How could an increase in water vapor create either a positive or negative feedback effect? 2. Carbon dioxide is considered the main greenhouse gas because its widely abundant and contributes the most to the greenhouse effect. Even though it can be less potent, it is six times more prominent than other gases. An increase in water vapor can cause a positive feedback effect by creating a loop of increased water into the air by an increase of evaporation through an increase of temperature. A negative feedback effect loop sees an increase in clouds that shade or cool the earth. This could slow the warming by reflecting back more solar radiation into space. 1. How do scientists study the ancient atmosphere? Describe what a proxy indicator is, and give two examples. 2. Scientists study ancient atmosphere using ice cores. This study allows scientists to go back 800,00 years over 8 glacial cycles. Drilling into the cores give scientists samples from bubbles that contain small samples of the atmosphere. A proxy indicator is a type of indict evidence that serves as a substitute for direct measurement. It can shed light on past climates. Two examples are ice caps and glaciers. 3. Has simulating climate change with computer programs been effective in helping us predict climate? How do these programs work? 4. Computer programs simulating climate change has helped us...
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