Hot topic.

• Position: Global warming - Cover story

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Everyone seems to be talking--or singing, or making a movie--about global warming. But despite rising awareness, misconceptions abound about what scientists prefer to call climate change. Take our pop quiz and find out how much you really know.

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TRUE OR FALSE (1-12)

1. The concentration of carbon dioxide in the atmosphere today is 35 percent higher than at the start of the Industrial Revolution, around 1750.

2. Eleven of the 12 years from 1995 to 2006 were among the 12 warmest since instrument records began, in 1850.

3. Ocean life is shielded from the effects of carbon dioxide buildup and climate change.

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4. China currently contributes the most carbon dioxide to the atmosphere.

5. Earth has been warmer in the past.

6. Some kinds of particulate pollution in the atmosphere counteract global warming by reducing the solar radiation that reaches Earth's surface.

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7. No place on Earth is, on average, colder today than it was 100 years ago.

8. Natural phenomena, including volcanic eruptions, trap heat close to the surface of Earth and are a major cause of global warming.

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9. Scientists derive evidence of the composition of Earth's atmosphere hundreds of thousands of years ago from air bubbles in ancient ice.

10. Livestock is a significant contributor of greenhouse gases.

11. As average global temperature rises, average precipitation increases.

12. Biofuels like ethanol [which is made from corn] and biodiesel (which is mostly from soybeans) can help reduce greenhouse gas emissions.

    MULTIPLE CHOICE (13-16)

13. By how much do scientists estimate that the global sea fever rose in the 20th century?

    1. zero

    2. 6-9 inches

    3. 3-4 feet

    4. 21-23 feet

14. By how much do scientists estimate the global sea level would rise if all of Greenland's glacial ice melted?

    1. zero

    2. 6-9 inches

    3. 3-4 feet

    4. 21-23 feet

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15. Which two of the following are not heat-trapping gases?

    1. carbon dioxide

    2. nitrogen

    3. water vapor

    4. ozone

    5. oxygen

16. Since 1961, the oceans have absorbed what percentage of the heat that has been added to the climate system?

    1. 50 percent

    2. 20 percent

    3. 80 percent

    4. 15 percent

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    The questions and answers are from David A. McConnell and David N. Steer, professors of geology at the University of Akron, in Ohio; Martin Ruzek of Earth System Science Education for the 21st Century, which is sponsored by NASA; and Debbie...