Astronomy test 3
What motivated Arrhenius to calculate how changes in carbon dioxide might affect the climate?
He was seeking to understand the causes of ice ages
The greenhouse effect raises Earth's surface temperature because the infrared light radiated by Earth's surface ______
is absorbed by greenhouse gases, slowing the escape of this energy to space
Current CO2 levels are higher than they have been at any other time during the history of the human species.
true
The atmospheres of Venus and Mars are primarily composed of carbon dioxide. Why is the surface of Venus so much hotter than the surface of Mars?
Venus' atmosphere is thousands of times thicker than Mars' atmosphere.
Why would the weather become more severe as the greenhouse effect increased?
Warming would increase the evaporation of the oceans, leading to more water in the atmosphere and more frequent and severe storms.
Which feature in this photo of the full moon is one of the lunar maria?
1, smooth dark regions
The CO2 concentration of the atmosphere has increased by about ________ since 1750.
100 parts-per-million
This diagram represents the conveyor-like action of plate tectonics on Earth. Which numbered position represents a place where new crust is emerging on the seafloor?
2
According to current climate models and given the current emission rate of carbon dioxide, how much will the Earth's average temperature increase by the end of this century?
2-5 degrees celsius
The total CO2 concentration of the atmosphere has increased by about ________ since 1750. Refer to the figure above.
25%
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 celsius
In the greenhouse effect, what is the direct cause of extra heating of the Earth's surface?
Additional carbon dioxide makes the atmosphere more opaque to infrared light, trapping more of the infrared light emitted by Earth.
Why does the burning of fossil fuels increase the greenhouse effect on Earth?
Burning releases carbon dioxide into the atmosphere.
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
Why do most scientists accept the claim that climate change is being caused by human activity?
Computer models that include the effects of human activity correctly predict the current trend of increasing temperatures. Computer models correctly reproduce past climate variations. Computer models that do not include the effects of human activity do not correctly predict the current trend of increasing temperatures. Levels of atmospheric carbon dioxide show a sharp increase since the industrial revolution.
All the following statements are true. Which two represent the two facts that lead us to expect Earth to be warming up as a result of human activity? Be sure to choose two of the statements below.
Human activity is increasing the concentration of carbon dioxide and other greenhouse gases in the atmosphere. Greenhouse gases make Earth warmer than it would be otherwise.
Why does Venus have such a large difference in temperature between its "no atmosphere" temperature and its actual temperature?
It has a large amount of carbon dioxide in its atmosphere
Considering Earth's climate, what is the importance of the carbon dioxide (CO2) cycle?
It helps regulates the carbon dioxide concentration in our atmosphere, keeping temperatures moderate.
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
Given the rate at which human activity is increasing CO2 levels, why can we not depend on the natural CO2 cycle to prevent global warming?
It operates too slowly
What is the importance of the carbon dioxide (CO2) cycle?
It regulates the carbon dioxide concentration of our atmosphere, keeping temperatures moderate.
This photo was taken on the surface of
Mars
These four photos show features of Earth that change with time, some fast and some slow. Which of these features could not exist if Earth did not have a magnetic field?
Northern lights
Which of the following statements about the greenhouse effect is true?
One result of an increased greenhouse effect on Earth may be an increased number of severe storms. The burning of fossil fuels increases the greenhouse effect on Earth because of the release of carbon dioxide. Without the naturally occurring greenhouse effect, Earth would be too cold to have liquid oceans. A weak greenhouse effect operates on Mars.
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
What does this figure tell us?
The current level of carbon dioxide in our atmosphere is higher than it has been at any time during the past 800,000 years.
This image shows two tall volcanoes on Venus. Why is it yellow?
The yellow color is arbitrary, since this image was created with radar data rather than visible light
What is the significance of the yellow lines on this map of Earth?
They represent boundaries between the plates that make up Earth's lithosphere.
Earth is habitable in part due to the greenhouse effect.
True
Earth outgassed as much carbon dioxide as Venus, but on Earth most of it is locked up in the oceans and rocks.
True
The current atmospheric concentration of carbon dioxide on Earth is at its highest in over a million years.
True
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
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 of the statements below are true. Which one gives the primary reason why the surface of Venus today is some 450°C hotter than the surface of Earth?
Venus has a much stronger greenhouse effect than Earth.
Which of the following is the most basic definition of a greenhouse gas?
a gas that absorbs infrared light
What do we mean by a runaway greenhouse effect?
a greenhouse effect that keeps getting stronger until all of a planet's greenhouse gases are in its atmosphere
On the graphs shown, you can identify an ice age by looking for __________.
a trough (bottom of a dip) on the temperature graph
Earth's atmosphere contains only small amounts of carbon dioxide because
carbon dioxide dissolves in water, and most of it is now contained in the oceans and carbonate rocks.
How is carbon dioxide initially removed from the atmosphere?
dissolving carbon dioxide in water
What, if anything, do you think we should be doing to alleviate the threat of global warming
improve energy efficiency replace fossil fuels with alternative energy sources reduce the emissions of greenhouse gases
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
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?
more infrared light is absorbed in the lower atmosphere the average surface temperature rises
Which of the following is not directly a product of outgassing?
oxygen
Which two factors are critical to the existence of the carbon dioxide (CO2) cycle on Earth?
plate tectonics and liquid water oceans
Which of the following can act like a long-term "thermostat" for the Earth's average temperature?
the carbon dioxide cycle
What are fossil fuels?
the carbon-rich remains of plants that died millions of years ago
Suppose Earth's atmosphere had no greenhouse gases. This would cause Earth's average surface temperature to be
well below the freezing point of water.
The greenhouse effect makes Earth warmer than it would be otherwise by about
30 k
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.
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
Which of the following is not an expected consequence of the rising carbon dioxide concentration or global warming?
Animal deaths due to carbon dioxide poisoning
Of the four gases CO2, H2O, N2, and O2, which are greenhouse gases?
CO2 and H2O
Which wavelength does earth's surface emit the most thermal radiation?
Greatest: infrared Least: Ultraviolet, visible, X ray
Without greenhouse gases, water on Earth's surface would be completely frozen.
True
Scientists have confidence in the predictions of today's best climate models because they __________.
agree well with actual data for recent decades
Historically, there is no link between increased CO2 levels and higher average temperatures.
false
Which region of Earth has warmed the most in recent decades?
the Arctic
We are confident that rising CO2 levels are caused by the burning of fossil fuels because atmospheric CO2 now shows the same carbon isotope ratio as fossil fuels.
true
This figure summarizes the geological histories of the terrestrial worlds. Based on this figure, what can you conclude?
The most important factor in a planet's geological history is its size.
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.
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 aberage 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
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 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.
In order of Greatest to least: venus, Earth, Mars, Mercury
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.
Greatest to least: Venus, Earth, Mars, 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.
Greatest to least: Venus, Earth, Mars, Mercury
Mars' atmosphere is mostly carbon dioxide. Why does it not experience a runaway greenhouse effect like Venus?
Mars' atmosphere is too thin
This photo was taken from orbit around some planet. What planet is it, and how do you know?
Mars, because we see dried up riverbeds
When were the heat-trapping effects of gases that cause the greenhouse effect first measured by scientists?
More than 150 years ago
In what ways is Earth different from the other terrestrial planets?
Most of its surface is covered with liquid water. Its lithosphere is broken into plates that move around. It has a much higher percentage of oxygen in its atmosphere. Life can be found almost everywhere on its surface.
These four photos show features of Earth that change with time, some fast and some slow. Which one of these features is being shaped primarily by the process we call tectonics?
Mountains
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.
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
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
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?
We understand the physical mechanism of the greenhouse effect, through which carbon dioxide can increase a planet's temperature. Models of the greenhouse effect successfully predict the temperatures of Venus and Mars from their atmospheric carbon dioxide amounts. 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.
Earth's temperature remains fairly steady, which means that Earth must return nearly the same amount of energy to space that it recieves from the sun. In what form does Earth return most of this energy to space?
infrared light emitted by the surface and atmosphere, visible light reflected by the surface, and visible light reflected by clouds
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∘C and 19∘C
The energy that warms Earth's surface comes primarily in the form of
visible light from the sun
