Chapter 7 Homework

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

Using only pencil and paper calculations, Arrhenius concluded that a doubling of the carbon dioxide concentration would raise global temperatures by about

5 degrees C

The country that is currently the biggest user of energy in the world is

China

Which of the following Mars surface features provides dramatic evidence that volcanism has played a role in shaping the surface of Mars?

Olympus Mons

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

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?

-Earth's global average temperature has generally risen 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

Based on Planet Z's size, orbital distance, and rotation rate, which of the following properties is it likely to have?

-active volcanoes -active tectonics -an atmosphere produced by outgassing

Which of the following discoveries are attributed to Dr. Keeling and are shown in the Keeling Curve?

-atmospheric carbon dioxide levels are rising -atmospheric carbon dioxide has seasonal variation

What are key features of any series of measurements that claim to measure changes in carbon dioxide levels over time?

-they must involve scrupulous attention to detail and integrity -they must use stable and reliable instruments

Each statement below represents a feature that has been claimed to exist on Mars. Sort the statements into the correct bin according to whether each is a feature that actually exists, that does not actually exist, or that might exist but about which we cannot yet draw a definitive conclusion.

Real Mars: -minerals of types known to form in liquid water -abundant water ice -dried-up river beds Imaginary Mars: -frequent rainfall and snowfall -surface pools of liquid water -cities built by an ancient civilization -... canals Unknown Mars: -microscopic life -underground pockets of liquid water

Regarding his affiliation to a US political party Dr. Keeling was a registered

Republican

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?

Venus

In Part A, you found that Planet Z should not have strong winds and violent storms. What single change to Planet Z's characteristics would cause it to have strong winds and violent storms?

a faster rotation rate

In Part A, you found that Planet Z should not have polar ice caps or liquid water. What single change to Planet Z's characteristics would allow it to have these things?

a greater distance from its star

In Part A, you found that Planet Z should not have seasons. What single change to Planet Z's characteristics would cause it to have seasons?

a larger tilt axis

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

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

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)?

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

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?

emissions of carbon dioxide rose much faster than Arrhenius had anticpated

According to the article, ice ages were probably caused by

low atmospheric carbon dioxide amplifying the effects of small wobbles in Earth's orbit

According to the article, some people who doubt the existence of global warming claim that carbon dioxide does not actually trap heat. This claim is

proved incorrect through experiments that even high school students can do in class

Assuming that features you see on Mars are similar to features found on Earth, what would a casual inspection of the interactive photo of Mars lead you to suspect about water on Mars?

surface water only exists as frozen ice

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

According to the article, the legitimate climate scientists who do not see global warming as a threat and are influential in congress hold the view that

the greenhouse effect is real and carbon dioxide level are rising, but there are feedback mechanisms that will prevent global warming from becoming a big deal

What type of graph (or curve) is attributed to the scientist in the article?

the rising graph of CO2 with an annual wiggle up and down

According to scientists, the naturally occurring greenhouse effect makes Earth about 31∘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

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

varied between about 7 degrees C and 19 degrees C

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

visible light from the Sun

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

Percival Lowell's claims of a Martian civilization generated great public interest, but other scientists of his time were highly skeptical of these claims. Which two of the following statements (which are all true) explain why other scientists of the late 19th and early 20th centuries rejected Lowell's claims?

-Lowell's canals followed perfectly straight lines for thousands of kilometers -Lowell's canals did not appear in photographs of Mars taken through telescopes

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

Go to the screen in the interactive figure called "Major Geological Features." Which of the following statements about the Tharsis Bulge, often simply called "Tharsis," are true?

-one end of Valles Marineris is connected to Tharsis -Tharsis has several large volcanoes -Tharsis has higher elevation than surrounding regions

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

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?

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

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

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?

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

The image below shows a rock formation nicknamed "the face on Mars" that was taken by the Viking 1 orbiter in 1976. Given the clear resemblance to a face, what is an appropriate scientific reaction to this image?

assume it is most likely a coincidental result of light and shadow, and plan higher resolution follow-up observations

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.

from left to right: 1. Venus 2. Earth 3. Mars 4. Mercury

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.

from left to right: 1. Venus 2. Earth 3. Mars 4. Mercury

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

from left to right: 1. infrared 2-4. rest equal

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.

from left to right: 1. venus 2. earth 3. mars 4. mercury

You have found that Planet Z should have active tectonics and volcanism and an atmosphere produced by volcanic outgassing. What single factor explains why the planet should have these characteristics?

has a large size for a terrestrial planet

What motivated Arrhenius to calculate how changes in carbon dioxide might affect the climate?

he was seeking to understand the cause of ice ages

Go to the screen in the interactive figure called "Key Evidence of Water," then zoom in on the "Southern Highlands." Which geologic processes are most clearly evident in the southern highlands?

impact cratering and erosion

the greenhouse effect raises Earth's surface temperature (from what it would be otherwise) because the infrared light radiated by Earth's surfacee

is absorbed by greenhouse gases, slowing the escape of this energy to space

what happens to the energy that the ground absorbs in the form of visible sunlight?

it is returned upward in the form of infrared light

On a cloudless day, what happens to most of the visible light headed toward Earth?

it reaches Earth's surface, where some is reflected and some is absorbed

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