Climate change has been linked to greenhouse gases in Earth’s atmosphere that allow sunlight to reach the planet’s surface while trapping the infrared energy that it emits. While the most abundant greenhouse gas is water vapor, human activities have only a small direct influence on its overall concentration, and its residence time (the time it stays in the atmosphere) is only nine days. The other major greenhouse gases are carbon dioxide and methane, and their concentrations in Earth’s atmosphere have been increasing since the mid-eighteenth century, due particularly to the burning of fossil fuels, the clearing of forests, and other changes in land use. Molecules of carbon dioxide and methane stay in the atmosphere for years after they are emitted-their residence times are between 5 and 200 years (carbon dioxide) and 12 years (methane)-so human activities have long-term effects.
Evidence of these effects can often be found on mountains. For instance, the clearest direct evidence that concentrations of carbon dioxide are increasing around the world comes from continuous measurements taken since March 1958 near the summit of Mauna Loa, Hawaii, at an altitude of 3,397 meters. The site was chosen by the United States Weather Bureau after it was unable to find anywhere in the continental United States where the air was clean enough. The atmospheric scientist Charles Keeling’s original reason for monitoring carbon dioxide was to better understand the daily cycle of its concentration in the atmosphere. However, within a few years, he had identified a seasonal cycle-because vegetation in the Northern Hemisphere absorbs carbon dioxide in summer and releases it in winter-and also discovered that, each year, concentrations were higher. Since 1958， the concentration of carbon dioxide at Mauna Loa has increased from 317 to over 400 parts per million. There is now a global consensus that Earth’s climate is changing because concentrations of carbon dioxide and other greenhouse gases are increasing as a result of human activities.
Mountains are not only where the primary cause of climate change has been measured, but they are where crucial evidence of its effects can be seen. Two of the most compelling types of evidence are the melting of glaciers and the fact that plants are growing at ever higher elevations on mountain summits. An international program of glacier monitoring began in 1894， as it was hoped that long-term observations would provide insights into processes of climate change, such as the occurrence of ice ages. Initially, the program focused on measuring the lengths of glaciers. Subsequently, the monitoring program was expanded to include the measurement of the mass balance of glaciers-the difference between the inputs of snowfall and the losses, mainly by melting-and the use of images from satellites. The great benefit of these images is that they provide complete coverage of areas that are often not easily accessible, such as many glaciated areas. Since 1986， the resulting standardized data on changes in glaciers, provided by scientists in over thirty countries, has been compiled by the World Glacier Monitoring Service. These data show that the world’s glaciers are shrinking-and at an accelerating rate. While the primary reason is a warming atmosphere, an additional cause, also of human origin, is the deposition of fine particles of black carbon, or soot, on the surface of glaciers. This comes mainly from engines and the burning of coal and other biofuels. Because soot absorbs more radiation than ice, its presence increases rates of glacier melt. This phenomenon occurred in the European Alps in the nineteenth century, so this was the region where the rate of glacier melting was greatest at the time, and it is currently happening in the Himalaya.
While long-term measurements of carbon dioxide and glaciers were planned, finding evidence of alpine plants growing at higher elevations was largely a lucky accident.Early in the twentieth century, the Swiss botanist Josias Braun-Blanquet climbed many peaks in the Swiss Alps. While on their summits, he recorded the highest specimens of each plant species. In the early 1990s, two young Austrian botanists, Michael Gottfried and Harald Pauli, returned to the peaks that Braun-Blanquet had climbed and repeated his measurements. They found a statistically significant increase in the number of species on the summits. These changes could then be correlated to changes in regional climates.
1
Climate change has been linked to greenhouse gases in Earth’s atmosphere that allow sunlight to reach the planet’s surface while trapping the infrared energy that it emits. While the most abundant greenhouse gas is water vapor, human activities have only a small direct influence on its overall concentration, and its residence time (the time it stays in the atmosphere) is only nine days. The other major greenhouse gases are carbon dioxide and methane, and their concentrations in Earth’s atmosphere have been increasing since the mid-eighteenth century, due particularly to the burning of fossil fuels, the clearing of forests, and other changes in land use. Molecules of carbon dioxide and methane stay in the atmosphere for years after they are emitted-their residence times are between 5 and 200 years (carbon dioxide) and 12 years (methane)-so human activities have long-term effects.
The word “it”in the first sentence of paragraph 1 refers to
Aclimate change
BEarth’s atmosphere
Cthe planet’s surface
Dinfrared energy
2
Climate change has been linked to greenhouse gases in Earth’s atmosphere that allow sunlight to reach the planet’s surface while trapping the infrared energy that it emits. While the most abundant greenhouse gas is water vapor, human activities have only a small direct influence on its overall concentration, and its residence time (the time it stays in the atmosphere) is only nine days. The other major greenhouse gases are carbon dioxide and methane, and their concentrations in Earth’s atmosphere have been increasing since the mid-eighteenth century, due particularly to the burning of fossil fuels, the clearing of forests, and other changes in land use. Molecules of carbon dioxide and methane stay in the atmosphere for years after they are emitted-their residence times are between 5 and 200 years (carbon dioxide) and 12 years (methane)-so human activities have long-term effects.
According to paragraph 1,all of the following are true about greenhouse gases in Earth’s atmosphere EXCEPT:
ACarbon dioxide and methane concentrations are more likely to be affected by human activity than are water vapor concentrations.
BMethane and carbon dioxide concentrations in the atmosphere have been increasing for over 200 years.
CMethane is found in larger concentrations in the atmosphere than either water vapor or carbon dioxide.
DCarbon dioxide and methane remain in the atmosphere longer than water vapor.
3
Climate change has been linked to greenhouse gases in Earth’s atmosphere that allow sunlight to reach the planet’s surface while trapping the infrared energy that it emits. While the most abundant greenhouse gas is water vapor, human activities have only a small direct influence on its overall concentration, and its residence time (the time it stays in the atmosphere) is only nine days. The other major greenhouse gases are carbon dioxide and methane, and their concentrations in Earth’s atmosphere have been increasing since the mid-eighteenth century, due particularly to the burning of fossil fuels, the clearing of forests, and other changes in land use. Molecules of carbon dioxide and methane stay in the atmosphere for years after they are emitted-their residence times are between 5 and 200 years (carbon dioxide) and 12 years (methane)-so human activities have long-term effects.
Evidence of these effects can often be found on mountains. For instance, the clearest direct evidence that concentrations of carbon dioxide are increasing around the world comes from continuous measurements taken since March 1958 near the summit of Mauna Loa, Hawaii, at an altitude of 3,397 meters. The site was chosen by the United States Weather Bureau after it was unable to find anywhere in the continental United States where the air was clean enough. The atmospheric scientist Charles Keeling’s original reason for monitoring carbon dioxide was to better understand the daily cycle of its concentration in the atmosphere. However, within a few years, he had identified a seasonal cycle-because vegetation in the Northern Hemisphere absorbs carbon dioxide in summer and releases it in winter-and also discovered that, each year, concentrations were higher. Since 1958， the concentration of carbon dioxide at Mauna Loa has increased from 317 to over 400 parts per million. There is now a global consensus that Earth’s climate is changing because concentrations of carbon dioxide and other greenhouse gases are increasing as a result of human activities.
Which of the following best describes the relationship of paragraph 2 to paragraph 1？
AParagraph 2 describes an early effort by scientists to solve a problem described in paragraph 1.
BParagraph 2 describes the lack of agreement among scientists about the causes of a phenomenon introduced in paragraph 1.
CParagraph 2 describes how one scientist collected measurements that confirmed the phenomenon presented in paragraph 1.
DParagraph 2 describes the difficulties scientists experienced when trying to measure a phenomenon described in paragraph 1.
4
Evidence of these effects can often be found on mountains. For instance, the clearest direct evidence that concentrations of carbon dioxide are increasing around the world comes from continuous measurements taken since March 1958 near the summit of Mauna Loa, Hawaii, at an altitude of 3,397 meters. The site was chosen by the United States Weather Bureau after it was unable to find anywhere in the continental United States where the air was clean enough. The atmospheric scientist Charles Keeling’s original reason for monitoring carbon dioxide was to better understand the daily cycle of its concentration in the atmosphere. However, within a few years, he had identified a seasonal cycle-because vegetation in the Northern Hemisphere absorbs carbon dioxide in summer and releases it in winter-and also discovered that, each year, concentrations were higher. Since 1958， the concentration of carbon dioxide at Mauna Loa has increased from 317 to over 400 parts per million. There is now a global consensus that Earth’s climate is changing because concentrations of carbon dioxide and other greenhouse gases are increasing as a result of human activities.
The phrase “continuous measurements”in the passage means measurements that are
Aalways taken from the same place
Bbeing taken all the time
Ccompared to other measurements
Dtaken by many scientists
5
Evidence of these effects can often be found on mountains. For instance, the clearest direct evidence that concentrations of carbon dioxide are increasing around the world comes from continuous measurements taken since March 1958 near the summit of Mauna Loa, Hawaii, at an altitude of 3,397 meters. The site was chosen by the United States Weather Bureau after it was unable to find anywhere in the continental United States where the air was clean enough. The atmospheric scientist Charles Keeling’s original reason for monitoring carbon dioxide was to better understand the daily cycle of its concentration in the atmosphere. However, within a few years, he had identified a seasonal cycle-because vegetation in the Northern Hemisphere absorbs carbon dioxide in summer and releases it in winter-and also discovered that, each year, concentrations were higher. Since 1958， the concentration of carbon dioxide at Mauna Loa has increased from 317 to over 400 parts per million. There is now a global consensus that Earth’s climate is changing because concentrations of carbon dioxide and other greenhouse gases are increasing as a result of human activities.
According to paragraph 2,the discoveries that resulted from Charles Keeling’s observations at Mauna Loa included which of the following?
AThe concentration of carbon dioxide in the atmosphere varied according to a daily cycle.
BThe concentration of carbon dioxide in the atmosphere varied from summer to winter.
CThe presence of vegetation caused carbon dioxide concentrations in the atmosphere to increase year after year.
DCarbon dioxide concentrations as high as those at Mauna Loa were not present elsewhere in the United States.
6
Mountains are not only where the primary cause of climate change has been measured, but they are where crucial evidence of its effects can be seen. Two of the most compelling types of evidence are the melting of glaciers and the fact that plants are growing at ever higher elevations on mountain summits. An international program of glacier monitoring began in 1894， as it was hoped that long-term observations would provide insights into processes of climate change, such as the occurrence of ice ages. Initially, the program focused on measuring the lengths of glaciers. Subsequently, the monitoring program was expanded to include the measurement of the mass balance of glaciers-the difference between the inputs of snowfall and the losses, mainly by melting-and the use of images from satellites. The great benefit of these images is that they provide complete coverage of areas that are often not easily accessible, such as many glaciated areas. Since 1986， the resulting standardized data on changes in glaciers, provided by scientists in over thirty countries, has been compiled by the World Glacier Monitoring Service. These data show that the world’s glaciers are shrinking-and at an accelerating rate. While the primary reason is a warming atmosphere, an additional cause, also of human origin, is the deposition of fine particles of black carbon, or soot, on the surface of glaciers. This comes mainly from engines and the burning of coal and other biofuels. Because soot absorbs more radiation than ice, its presence increases rates of glacier melt. This phenomenon occurred in the European Alps in the nineteenth century, so this was the region where the rate of glacier melting was greatest at the time, and it is currently happening in the Himalaya.
The word “compelling”in the passage is closest in meaning to
Aconvincing
Bshocking
Ccommon
Dobvious
7
Mountains are not only where the primary cause of climate change has been measured, but they are where crucial evidence of its effects can be seen. Two of the most compelling types of evidence are the melting of glaciers and the fact that plants are growing at ever higher elevations on mountain summits. An international program of glacier monitoring began in 1894， as it was hoped that long-term observations would provide insights into processes of climate change, such as the occurrence of ice ages. Initially, the program focused on measuring the lengths of glaciers. Subsequently, the monitoring program was expanded to include the measurement of the mass balance of glaciers-the difference between the inputs of snowfall and the losses, mainly by melting-and the use of images from satellites. The great benefit of these images is that they provide complete coverage of areas that are often not easily accessible, such as many glaciated areas. Since 1986， the resulting standardized data on changes in glaciers, provided by scientists in over thirty countries, has been compiled by the World Glacier Monitoring Service. These data show that the world’s glaciers are shrinking-and at an accelerating rate. While the primary reason is a warming atmosphere, an additional cause, also of human origin, is the deposition of fine particles of black carbon, or soot, on the surface of glaciers. This comes mainly from engines and the burning of coal and other biofuels. Because soot absorbs more radiation than ice, its presence increases rates of glacier melt. This phenomenon occurred in the European Alps in the nineteenth century, so this was the region where the rate of glacier melting was greatest at the time, and it is currently happening in the Himalaya.
According to paragraph 3,which of the following is true of the World Glacier Monitoring Service?
AIts findings contradicted those of the international glacier monitoring program begun in 1894.
BIt focuses on the information available on glacier length as an indication of the extent of climate change.
CIt sent out one group of scientists to make measurements in 30 countries to standardize the data it received.
DIt collects data about glaciers taken from satellite imagery.
8
Mountains are not only where the primary cause of climate change has been measured, but they are where crucial evidence of its effects can be seen. Two of the most compelling types of evidence are the melting of glaciers and the fact that plants are growing at ever higher elevations on mountain summits. An international program of glacier monitoring began in 1894， as it was hoped that long-term observations would provide insights into processes of climate change, such as the occurrence of ice ages. Initially, the program focused on measuring the lengths of glaciers. Subsequently, the monitoring program was expanded to include the measurement of the mass balance of glaciers-the difference between the inputs of snowfall and the losses, mainly by melting-and the use of images from satellites. The great benefit of these images is that they provide complete coverage of areas that are often not easily accessible, such as many glaciated areas. Since 1986， the resulting standardized data on changes in glaciers, provided by scientists in over thirty countries, has been compiled by the World Glacier Monitoring Service. These data show that the world’s glaciers are shrinking-and at an accelerating rate. While the primary reason is a warming atmosphere, an additional cause, also of human origin, is the deposition of fine particles of black carbon, or soot, on the surface of glaciers. This comes mainly from engines and the burning of coal and other biofuels. Because soot absorbs more radiation than ice, its presence increases rates of glacier melt. This phenomenon occurred in the European Alps in the nineteenth century, so this was the region where the rate of glacier melting was greatest at the time, and it is currently happening in the Himalaya.
According to paragraph 3,why was the rate of glacier melting in the nineteenth century greater in the European Alps than it was in other places?
AWarming of the atmosphere above the Alps at the time was occurring especially rapidly and intensely.
BThe extreme elevation of the Alps caused them to experience more warming than other mountain regions did.
CThe Alps had more ice for absorbing radiation than did other tall mountain ranges at the time.
DCarbon particles from industrial processes were deposited in the Alps earlier than they were in other mountain regions.
9
While long-term measurements of carbon dioxide and glaciers were planned, finding evidence of alpine plants growing at higher elevations was largely a lucky accident.[■] Early in the twentieth century, the Swiss botanist Josias Braun-Blanquet climbed many peaks in the Swiss Alps. [■] While on their summits, he recorded the highest specimens of each plant species. [■] In the early 1990s, two young Austrian botanists, Michael Gottfried and Harald Pauli, returned to the peaks that Braun-Blanquet had climbed and repeated his measurements. [■] They found a statistically significant increase in the number of species on the summits. These changes could then be correlated to changes in regional climates.
Look at the four squaresthat indicate where the following sentence could be added to the passage
A later generation of scientists found a new use for that data.
Where would the sentence best fit？Click on a square sentence to the passage.
10
Observations taken in mountain environments have provided evidence of climate change related to human activities.
AAs Earth’s climate has warmed, the residence times of the most abundant greenhouse gases have rapidly increased, further contributing to climate warming.
BScientist Charles Keeling discovered that atmospheric carbon dioxide concentrations followed a daily rather than a seasonal cycle in northern mountain ranges with vegetation.
CIn the 1990s, scientists noted the increase in the number of alpine plant species at higher elevations over the twentieth century and connected it to regional climate changes.
DMeasurements taken on Mauna Loa over decades offer evidence of increasing concentrations of atmospheric carbon dioxide, one of the major greenhouse gases.
ERecently, the monitoring of glaciers worldwide has added to older data to show that the warming climate and soot deposition are accelerating glacier melt.
FSamples taken by the botanist Braun-Blanquet confirmed earlier theories that mountain vegetation absorbs carbon dioxide in summer and releases it in winter.
