Chapter 10

Click on the first tab at the top of the interactive figure (labeled "The Greenhouse Effect"), then explore what happens as you click among the buttons (labeled "none," "low," "medium," and "high") that adjust the greenhouse gas concentration. Which of the following occur as the greenhouse gas concentration increase?

- the average surface temperature rises - more infrared light is absorbed in the lower atmosphere

Click the third tab (labeled "Global Warming"), then explore the graph and the expanded views you will find by clicking the "?" buttons. Which of the following statements are supported by the data shown? a) Earth's global average temperature has generally risen over the past century. b) Earth's global temperature today is higher than it has ever been before. Human activity has caused the carbon dioxide concentration to swing up and down wildly over the past 800,000 years. c) Rises in global average temperature tend to be closely associated with rises in atmospheric carbon dioxide concentration. d) Atmospheric carbon dioxide levels have risen dramatically over the past century.

-Rises in global average temperature tend to be closely associated with rises in atmospheric carbon dioxide concentration -Atmospheric carbon dioxide levels have risen dramatically over the past century -Earth's global average temperature has generally risen over the past century.

Earth's temperature remains fairly steady, which means that Earth must return nearly the same amount of energy to space that it receives from the Sun. In what form(s) does Earth return most of this energy to space?

-infrared light emitted by the surface and atmosphere -visible light reflected by clouds -visible light reflected by the surface

Although the data show only a correlation between the carbon dioxide concentration and the global average temperature, scientists have other reasons to think that a rise in the carbon dioxide concentration actually causes a rise in the global average temperature. All of the following statements are true. Which statements lend support to the idea that carbon dioxide is a cause of planetary warming?

-models of Earth's climate that include recent increases in the carbon dioxide concentration match observed temperature increases better than those that do not include it-models of the greenhouse effect successfully predict the temperature of Venus and Mars from their atmospheric carbon dioxide amounts-We understand the physical mechanism of the greenhouse effect, through which carbon dioxide can increase a planet's temperature

What would the Venus "no greenhouse" temperature be if its clouds were more transparent, giving a reflectivity the same as Earth's?

29

Make a prediction: If the rise in carbon dioxide concentration continues at its current pace, the concentration in the year 2050 will be about _____ parts per million.

460

What would the surface temperature be in this example if the greenhouse effect simply increased the surface temperature by the same number of degrees that it does today?

539

Using only pencil and paper calculations, Arrhenius concluded that a doubling of the carbon dioxide concentration would raise global temperatures by about _____. a) 1° C b) 2° C c) 5° C d) 15° C

5° C

All of the following have occurred over long periods of time on Earth. Which one is not thought to have played a major role in long-term changes in Earth's climate? a) Changes in the Earth's axis tilt. b) Changes in the atmospheric concentration of greenhouse gases. c) Changes in the Earth's overall reflectivity. d) A gradual rise in the atmospheric content of oxygen.

A gradual rise in the atmospheric content of oxygen.

Which of the following best describes how the greenhouse effect works?

A planet's surface absorbs visible sunlight and returns this absorbed energy to space as infrared light. Greenhouse gases slow the escape of this infrared radiation, which thereby heats the lower atmosphere.

Since the time Arrhenius made his prediction, the carbon dioxide concentration has risen by about 30% and the global average temperature has risen by about 1°C. Which statement below best describes how scientists should evaluate Arrhenius's prediction? a) We cannot evaluate Arrhenius's prediction, because he made a prediction for a 50% rise in the carbon dioxide concentration and the actual rise since his time has been only about 30%. b) Although Arrhenius's prediction was not exact, the actual change is similar enough to the predicted change to validate the general idea that a rising carbon dioxide concentration would lead to global warming. c) The actual change is so much lower than Arrhenius predicted that we must conclude he was wrong in his assumption that a rising carbon dioxide concentration would lead to global warming. d) The actual change is so much higher than Arrhenius predicted that we must conclude that he was incorrect in assuming that the carbon dioxide concentration affects the climate.

Although Arrhenius's prediction was not exact, the actual change is similar enough to the predicted change to validate the general idea that a rising carbon dioxide concentration would lead to global warming

Why is the Coriolis effect so weak on Venus?

Because Venus rotates so slowly.

Why is thermal escape of atmospheric gas much easier from the Moon than from Earth? a) Because the Moon's average surface temperature is lower than Earth's. b) Because the Moon lacks a global magnetic field, while Earth has one. c) Because the Moon's gravity is so much weaker than Earth's. d) Outgassing on the Moon releases gases with lower masses than does outgassing on Earth.

Because the Moon's gravity is so much weaker than Earth's

Why is Mars red? a) The red color of Mars is a result of the scattering of light in the Martian sky. b) The red color is caused by water ice chemically bound in surface rock. c) Chemical reactions between surface rock and atmospheric oxygen literally rusted the surface. d) Martian volcanoes released a much redder lava than volcanoes on Earth.

Chemical reactions between surface rock and atmospheric oxygen literally rusted the surface.

Click the fourth tab (labeled "Computer Models"), then explore how the graph changes as you click among the three buttons to its left. What is the primary message of the full graph (with all three curves shown)? a) Climate models successfully reproduce the major recent trend in temperature data only if both human and natural factors are included. b) Climate models can successfully reproduce the major recent trends in temperature data by considering natural factors alone. c) Climate models are unable to account for the major recent trend in temperature data.

Climate models successfully reproduce the major recent trend in temperature data only if both human and natural factors are included.

Suppose Earth were to cool down a little. How would the carbon dioxide cycle tend to restore temperatures to normal?

Cooler temperatures lead to slower formation of carbonate minerals in the ocean, so carbon dioxide released by volcanism builds up in the atmosphere and strengthens the greenhouse effect.

As you found in Part A, early Mars had both core convection and a strong magnetosphere. What is the connection between these two things? a) Core convection helps generate a magnetic field, and the magnetic field creates the magnetosphere. b) Core convection creates volcanism and outgassing, the gas creates the magnetosphere. c) Both core convection and a magnetosphere can exist only a very young planet. d)Both core convection and a magnetosphere are consequences of a strong greenhouse effect.

Core convection helps generate a magnetic field, and the magnetic field creates the magnetosphere.

Each of the following statements was either true for Mars in the distant past (early Mars) or is true for Mars today. Sort the statements by dragging each into the correct bin.

Early Mar -Some craters held lakes of water. -Strong magnetosphere. -Substantial volcanism and outgassing. -Strong greenhouse effect. -Core convection Mars Today -Very weak greenhouse effect. -Surface pressure too low for stable liquid water. -Solar wind strips atmospheric gas

What would happen to Earth if we somehow moved our planet to the orbit of Venus? a) The fact that we have oceans would moderate the temperature change because of moving our planet, so temperature would hardly change at all. b) Being so much closer to the Sun would almost immediately cause the surface of Earth to melt, and all our cities would then be destroyed by the hot lava. c) Temperatures would rise only slightly, but enough to melt the polar caps. d) Earth would suffer a runaway greenhouse effect and become as hot as or hotter than Venus.

Earth would suffer a runaway greenhouse effect and become as hot as or hotter than Venus

Arrhenius was not particularly alarmed by his discovery at the time. What changed that made later scientists become much more concerned about the climate effects of carbon dioxide? a) Emissions of carbon dioxide rose much faster than Arrhenius had anticipated. b) Scientists discovered errors in Arrhenius's calculations that made the effects of carbon dioxide much greater than he had expected. c) Scientists became concerned about carbon dioxide only after measurements showed the world was warming substantially. d) Scientists discovered that there is much more natural carbon dioxide in the atmosphere than Arrhenius had thought.

Emissions of carbon dioxide rose much faster than Arrhenius had anticipated.

In Part A, you found that Earth emits only infrared light. This infrared light can be absorbed by greenhouse gases, such as carbon dioxide and water vapor, in the atmosphere. In fact, all the terrestrial planets emit infrared light from their surfaces. The following images show the four terrestrial planets in our solar system. Rank these planets from left to right based on the total amount of infrared-absorbing greenhouse gases in their atmospheres, from greatest to least.

GREATEST Venus, Earth, Mars, Mercury LEAST

The following images represent four types (wavelength bands) of light. Rank these from left to right based on the amount of each that is emitted (as thermal radiation) by Earth's surface, from greatest to least. If you think that two (or more) types should be ranked as equal, drag one on top of the other(s) to show this equality.

GREATEST AMOUNT - infrared. EQUAL AT "LEAST AMOUNT - visible - ultraviolet - X-ray light

What motivated Arrhenius to calculate how changes in carbon dioxide might affect the climate? a) He knew that the carbon dioxide concentration was increasing and sought to understand how that would affect the climate. b) He was seeking to understand why the world was rapidly warming up. c) He was seeking to understand the causes of ice ages. d) He was seeking to understand the consequences of burning fossil fuels.

He was seeking to understand the causes of ice ages.

What key process underlies why Mars changed so much from its early conditions to its conditions today? a) Outgassing. b) Evaporation of its ocean. c) Interior cooling. d) Slowing of its rotation rate

Interior cooling.

As discussed in the video, the leading hypothesis for why Mars changed holds that interior cooling led to loss of its magnetosphere, allowing the solar wind to strip atmospheric gas away. How has the MAVEN mission provided evidence for this hypothesis? a) It has measured the strength of the magnetic field that Mars had long ago. b) It has measured rates of gas loss from the atmosphere today. c) It measured the amount of atmospheric gas that Mars had long ago. d) It has measured the rate at which Mars's interior has lost heat.

It has measured rates of gas loss from the atmosphere today

Which of the following statements about Earth's troposphere is not generally true? a) It is the layer of the atmosphere in which convection plays the most important role. b) It is a layer of the atmosphere in which temperature declines with increasing altitude. c) It is the layer of the atmosphere in which ozone absorbs dangerous ultraviolet light from the Sun. d) It is the lowest layer of the atmosphere.

It is the layer of the atmosphere in which ozone absorbs dangerous ultraviolet light from the Sun

Why doesn't Mars have a stratosphere? a) Its greenhouse effect is too weak. b) It is too small. c) It is too far from the Sun. d) It lacks a layer of ultraviolet absorbing gas.

It lacks a layer of ultraviolet absorbing gas.

Imagine that you visit an alien world that has an atmospheric composition similar to that of Earth (that is, mostly nitrogen and oxygen) and a surface atmospheric pressure of 1.2 bars. Which of the following statements best describes the effects of this pressure? a) It will feel quite similar to the atmospheric pressure on Earth. b) It will feel about like the pressure on a high mountaintop on Earth. c) It is so low that you'll need to wear a pressurized spacesuit to survive. d) It will feel crushing, like being deep under the ocean.

It will feel quite similar to the atmospheric pressure on Earth.

The following images show the four terrestrial planets in our solar system. Rank the planets from left to right based on the amount by which the greenhouse effect increases their surface temperatures, compared to what their temperatures would be without the greenhouse effect, from largest to smallest increase.

LARGEST INCREASE - Venus, - Earth, - Mars, - Mercury SMALLEST INCREASE

Put the major layers of Earth's atmosphere in to the correct order from the ground upward.

Lowest Altitude to Highest Altitude: Troposphere Stratosphere Thermosphere Exosphere

All of the following statements are true. Which one explains why Mars has lost so much more interior heat than Earth. a) Mars has lost much more atmospheric gas than Earth. b) Mars is farther from the Sun than Earth. c) Mars is smaller than Earth. d) Mars lacks a large moon. e) Mars has a much weaker greenhouse effect than Earth.

Mars is smaller than Earth

Does Venus have auroras around its poles, like Earth? Why or why not?

No, because it lacks a global magnetic field.

According to current science, why didn't oxygen begin to accumulate in the atmosphere for more than a billion years after life appeared on the Earth? a) Early forms of animal life consumed the oxygen released by plants during the first billion years of life on Earth. b) Oxygen released by life was removed from the atmosphere by chemical reactions with surface rocks until the surface rock could absorb no more. c) Oxygen released by life was removed from the atmosphere by dissolving in the ocean until the oceans could dissolve no more. d) Early life did not release oxygen, and oxygen-releasing organisms didn't evolve for a billion years after the earliest life.

Oxygen released by life was removed from the atmosphere by chemical reactions with surface rocks until the surface rock could absorb no more.

The following images show the four terrestrial planets in our solar system. Rank the planets from left to right based on the strength of the greenhouse effect occurring at their surfaces, from strongest to weakest.

STRONGEST Venus, Earth, Mars, Mercury WEAKEST

What does this figure tell us? a) Earth is now warmer than it has been at any time during the past 800,000 years. b) The current level of carbon dioxide in our atmosphere is higher than it has been at any time during the past 800,000 years. c) The current level of carbon dioxide in our atmosphere can be attributed to natural changes in Earth's climate. d) The current level of carbon dioxide in the atmosphere and the global average temperature are both higher today than at any other time during the past 800,000 years. e) The level of carbon dioxide in our atmosphere changes randomly with time, so there is no way to predict how it will change during the next century.

The current level of carbon dioxide in our atmosphere is higher than it has been at any time during the past 800,000 years.

Which of the following is not an expected consequence of global warming? a) A decrease in summer ice coverage of the Arctic Ocean. b) The entire Earth will warm up by the same amount. c) An increase in the number and/or severity of extreme weather events. d) An increase in sea level.

The entire Earth will warm up by the same amount.

According to scientists, the naturally occurring greenhouse effect makes Earth about 31∘C∘C warmer than it would be if there were no greenhouse gases in our atmosphere. How do scientists "know" what Earth's temperature would be without greenhouse gases?

They calculate this temperature from Earth's reflectivity and distance from the Sun.

In general terms, how do the temperature structures of the atmospheres of Venus and Mars differ from that of Earth?

They lack ultraviolet-absorbing stratospheres.

Which of the following best explains what scientists think happened to outgassed water vapor on Venus?

Ultraviolet light split the water molecules, and the hydrogen then escaped to space.

Now click the second tab (labeled "Terrestrial Planet Temperatures"), then explore what happens as you click the button that allows you to add or remove greenhouse gases. Which terrestrial planet would have its surface temperature the most dramatically changed if its greenhouse gases were removed from its atmosphere? a) Venus b) Mars c) Earth d)Mercury

Venus

All of the following statements are true. Which one provides strong observational support for the claim that greenhouse gases make a planet warmer than it would be otherwise?

Venus has a higher average temperature than Mercury.

All the statements are true. Which one gives the primary reason why the surface of Venus today is some 450ºC hotter than the surface of Earth?

Venus has a much stronger greenhouse effect than Earth.

Based solely on an understanding of the greenhouse effect (as displayed in the figure), which one of the following statements is true?

We should expect an increase in the greenhouse gas concentration to lead to global warming.

What is the difference between weather and climate? What is the difference between weather and climate? a) Weather refers to short-term changes in wind, rain, and temperature; climate refers to the long-term average of weather. b) Weather is something that we can control, and climate is not. c) Weather refers to atmospheric conditions in the troposphere; climate refers to atmospheric conditions in the stratosphere. d) Weather refers to small storms; climate refers to large storms.

Weather refers to short-term changes in wind, rain, and temperature; climate refers to the long-term average of weather.

X-rays from the Sun are absorbed primarily in Earth's

X-rays from the Sun are absorbed primarily in Eath's

On the graphs shown, you can identify an ice age by looking for

a trough (bottom of a dip) on the temperature graph

Greenhouse gases in the atmosphere, such as carbon dioxide and water vapor, make Earth warmer than it would be otherwise because these gases

absorb infrared light emitted by the surface

This photograph shows a hurricane from space. Why does it have the clockwise swirl?

because of the Coriolis effect

The "edge of space" occurs in the layer we call the

exosphere

These four photos show features of Earth that change with time, some fast and some slow. Which of these features is a direct result of the fact that Earth has a global magnetic field?

northern lights

Ultraviolet light from the Sun is absorbed primarily in Earth's

stratosphere

Based on the evidence that atmospheric carbon dioxide is a cause of planetary warming, what aspect of the graphs should most concern us?

the carbon dioxide concentration today is significantly higher than at any time in the past 800,000 years and is rapidly rising

Which characteristic of Earth explains why Earth has the ozone necessary for an ultraviolet-absorbing stratosphere?

the existence of photosynthetic life

Notice that the peaks and troughs on the temperature graph occur at the about the same times as peaks and troughs on the carbon dioxide graph. What can we infer from this fact alone?

there is a correlation between the carbon dioxide concentration and the global average temperature

Convection and weather occur primarily in Earth's

troposphere

The greenhouse effect causes warming primarily in Earth's

troposphere

The average temperature over the past 1000 years has been about 15∘C∘C. From the graphs, you can conclude that Earth's average temperature during the past 800,000 years has __________.

varied between about 7∘C∘C and 19∘C

The energy that warms Earth's surface comes primarily in the form of

visible light from the Sun