July 29, 2007
Pop Quiz: Climate Change

With an Oscar and a 24-hour benefit concert — not to mention the recent comprehensive report from the Intergovernmental Panel on Climate Change — the issue of global warming has taken on new urgency. But despite rising awareness, misconceptions abound about the realities of what scientists prefer to call climate change. Below, educators share some of what they think you should understand. Go to Answers


Program scientist, “Feeling the Heat: The Climate Challenge,” a new exhibition at the Birch Aquarium, Scripps Institution of Oceanography, at the University of California, San Diego.

1. How much do scientists estimate that global sea level rose in the 20th century?
a. zero
b. 6-9 inches
c. 3-4 feet
d. 21-23 feet

2. How much do scientists estimate global sea level would rise if all of Greenland’s glacial ice melted?
a. zero
b. 6-9 inches
c. 3-4 feet
d. 21-23 feet

3. Without the atmosphere’s natural greenhouse effect, Earth’s temperature would be:
a. 10-20F warmer
b. 30-40F warmer
c. 10-20°F cooler
d. 50-60F cooler

4. Which of the following is not a heat-trapping gas?
a. carbon dioxide
b. nitrogen
c. water vapor
d. ozone

5. Which of these processes adds carbon dioxide to the atmosphere?
a. burning fossil fuels
b. cement production
c. both of the above
d. neither of the above

6. Observations since 1961 show that the oceans have absorbed what percentage of the heat that has been added to the climate system?
a. 50 percent
b. 20 percent
c. 80 percent
d. 15 percent

7. Charles David Keeling took the first regular measurements of carbon dioxide in the atmosphere, at Mauna Loa in Hawaii. What best explains the variation in carbon dioxide concentration within each year?
a. Carbon dioxide levels decline from May to September because of photosynthesis by plants in the Northern Hemisphere.
b. Volcanic eruptions increase levels in winter.
c. Auto emissions increase levels during peak tourist season.
d. None of the above.


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

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

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

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

12. Ocean life is protected from the effects of carbon dioxide buildup and climate change.


Professors of geology, University of Akron, and authors of the new textbook “The Good Earth: Introduction to Earth Science.”

True or False
1. It is colder in winter than in summer because Earth is farther away from the sun in winter and closer in summer.
2. Global warming, the long-term increase in world temperatures, occurs mainly because certain chemicals we use thin the ozone layer, allowing more solar radiation to reach Earth’s surface.
3. An increase in the concentration of trace atmospheric gases, like carbon dioxide, contributes to higher global temperatures.
4. Natural phenomena, including volcanic eruptions, trap heat close to the surface of Earth and are a major cause of recent global warming.

5. Which statement is most accurate about the greenhouse effect?
a. It is good for life on Earth.
b. It is potentially harmful for life on Earth.
c. It has little direct impact on life on Earth.

6. Why is Earth warm enough to support life?
a. Radiation from the sun is absorbed by ozone in the stratosphere.
b. X-rays and gamma rays excite gas molecules in the lower atmosphere.
c. Infrared radiation leaving Earth’s surface is absorbed by gases in the lower atmosphere.


Program manager, Earth System Science Education for the 21st Century, a NASA-sponsored program to create undergraduate curriculum to study Earth as an interrelated system of air, water, land, life and society.


1. Earth has been warmer in the past.
2. No place on Earth is, on average, colder today than it was 100 years ago.
3. NASA tracks El Niño as a way of measuring global warming.
4. Livestock is a significant contributor of greenhouse gases.
5. China currently contributes the most carbon dioxide to the atmosphere.
6. As average global temperature rises, average precipitation increases.
7. Biofuels like ethanol and biodiesel can help reduce greenhouse gas emissions.

Copyright 2007 The New York Times Company