Bunuel
Since the early 20th century, researchers have sought to understand the relationship between volcanic eruptions and long-term climate patterns. Although early studies suggested a potential link, substantial evidence remained elusive until the 1990s, when Hansen and his colleagues compiled data indicating that large volcanic eruptions can inject sulfur dioxide (SO2) into the stratosphere, forming aerosols that reflect sunlight and temporarily cool the Earth's surface. This phenomenon is known as volcanic forcing. While volcanologists have recognized volcanic forcing for decades, its impact on global temperatures was not quantified until the development of satellite monitoring.
One prominent example is the eruption of Mount Pinatubo in 1991, which released approximately 20 million tons of SO2 into the atmosphere. In the two years following the eruption, average global temperatures decreased by approximately 0.5 degrees Celsius. On this basis, climatologists predicted that similar large eruptions would lead to temporary but measurable declines in global temperatures.
However, when the Eyjafjallajökull volcano erupted in Iceland in 2010, the anticipated cooling effect was negligible, prompting scientists to reassess their understanding of volcanic forcing. Robock and Mao proposed that the discrepancy could be explained by the height at which volcanic material was injected into the atmosphere. Eyjafjallajökull’s eruption, while disruptive to air travel, released much of its SO2 at lower altitudes, where aerosols dissipated relatively quickly due to a relative absence of stratospheric winds and had minimal long-term impact on global temperatures.
Further analysis revealed that tropical eruptions, such as Pinatubo, tend to have a more significant climatic effect because stratospheric winds can distribute aerosols globally. In contrast, eruptions at higher latitudes are more likely to release sulfur dioxide (SO2) at lower altitudes often leading to more localized and less enduring cooling. Robock and Mao concluded that while volcanic forcing remains an important component of climate models, not all eruptions contribute equally to global temperature changes.
Although this hypothesis is well-supported by empirical data, ongoing research aims to refine predictions by integrating additional factors, such as the chemical composition of volcanic emissions and their interaction with atmospheric water vapor. Understanding these variables is crucial for accurately modeling the role of volcanic activity in shaping the Earth’s climate.
1. The author of the passage would most likely agree with which of the following statements about the link between volcanic eruptions and global temperature changes?
A. Since volcanic forcing is a well-established phenomenon, further research should focus on its broader implications for global cooling trends.
B. Although volcanic eruptions can affect global temperatures, their impact is inconsistent and depends on multiple factors.
C. The influence of volcanic eruptions on global temperatures is minimal and unlikely to be a significant focus of future climate research.
D. The cooling effect of volcanic eruptions has been exaggerated, as the data on eruptions like Mount Pinatubo do not align with long-term temperature trends.
E. The primary factor influencing volcanic forcing is the magnitude of SO2 emissions, regardless of where the eruption occurs.
2. The passage provides information to support which of the following statements about volcanic eruptions at higher latitudes?
A. They release sulfur dioxide (SO2) at higher altitudes that allow for regional, rather than global, cooling effects.
B. They are less likely to release sulfur dioxide (SO2) at higher altitudes, minimizing their impact on localized temperatures.
C. They often release sulfur dioxide (SO2) into the stratosphere, but the aerosols dissipate more quickly than those from tropical eruptions.
D. They can produce short-term cooling effects, though their sulfur dioxide emissions are typically lower than those of tropical eruptions.
E. They are more likely to release sulfur dioxide (SO2) at lower altitudes, reducing their impact on global temperatures.
3. Which of the following most accurately describes the organization of the passage?
A. A hypothesis is introduced, evidence supporting it is presented, and a call for further research to strengthen the hypothesis is made.
B. A phenomenon is described, a prediction about its effects is made, and then evidence contradicting the prediction is analyzed.
C. Two competing explanations for a phenomenon are proposed, and one is shown to be more plausible based on empirical data.
D. A theory is described, and an example that aligns with the theory’s predictions is explored in detail.
E. A phenomenon is introduced, an exception to its typical outcome is explained, and a refined hypothesis accounting for the exception is proposed.
4. The passage provides information to support which of the following statements about the role of stratospheric winds in volcanic forcing?
A. Stratospheric winds are more likely to distribute aerosols globally if the volcanic eruption occurs at higher latitudes.
B. The effect of stratospheric winds on aerosol distribution is likely less significant following eruptions that release sulfur dioxide (SO2) at lower altitudes.
C. Stratospheric winds primarily influence the speed at which sulfur dioxide (SO2) from eruptions dissipates rather than its geographic spread.
D. Stratospheric winds are less effective at distributing aerosols when sulfur dioxide (SO2) is released at lower altitudes, regardless of latitude.
E. Stratospheric winds are responsible for preventing the formation of aerosols from sulfur dioxide (SO2) released at low altitudes.
Official Solution:1. The author of the passage would most likely agree with which of the following statements about the link between volcanic eruptions and global temperature changes?A. Since volcanic forcing is a well-established phenomenon, further research should focus on its broader implications for global cooling trends.
B. Although volcanic eruptions can affect global temperatures, their impact is inconsistent and depends on multiple factors.
C. The influence of volcanic eruptions on global temperatures is minimal and unlikely to be a significant focus of future climate research.
D. The cooling effect of volcanic eruptions has been exaggerated, as the data on eruptions like Mount Pinatubo do not align with long-term temperature trends.
E. The primary factor influencing volcanic forcing is the magnitude of SO2 emissions, regardless of where the eruption occurs.
A) Incorrect: The passage emphasizes that volcanic forcing is important but not universally applicable to all eruptions. The focus remains on the variability of its effects rather than its broader implications.
B) Correct: The passage consistently highlights that while volcanic eruptions can influence global temperatures, the impact varies based on factors like altitude and location of the eruption.
C) Incorrect: The passage suggests that volcanic forcing is significant in climate models, not minimal. It stresses ongoing research rather than dismissal of the phenomenon.
D) Incorrect: The passage does not suggest the cooling effect has been exaggerated. The Pinatubo case supports the hypothesis, and discrepancies are explained through other factors like eruption altitude.
E) Incorrect: The passage indicates that the altitude and location of the eruption, not just SO2 emissions, are critical in determining the extent of the cooling effect. 2. The passage provides information to support which of the following statements about volcanic eruptions at higher latitudes?A. They release sulfur dioxide (SO2) at higher altitudes that allow for regional, rather than global, cooling effects.
B. They are less likely to release sulfur dioxide (SO2) at higher altitudes, minimizing their impact on localized temperatures.
C. They often release sulfur dioxide (SO2) into the stratosphere, but the aerosols dissipate more quickly than those from tropical eruptions.
D. They can produce short-term cooling effects, though their sulfur dioxide emissions are typically lower than those of tropical eruptions.
E. They are more likely to release sulfur dioxide (SO2) at lower altitudes, reducing their impact on global temperatures.
A) Incorrect: While the part about regional cooling effects is partially true, this option distorts the overall message by emphasizing regional cooling due to sulfur dioxide (SO2) at higher altitudes which is not correct.
B) Incorrect: SO2 released by volcanic eruptions at higher latitudes can cause localized cooling.
C) Incorrect: The passage contradicts this by noting that high-latitude eruptions typically do not inject SO2 into the stratosphere.
D) Incorrect: The passage highlights altitude, not the amount of SO2, as the primary factor influencing cooling effects.
E) Correct: The passage explicitly states that eruptions at higher latitudes, like Eyjafjallajökull, release SO2 at lower altitudes, limiting their global temperature impact.
3. Which of the following most accurately describes the organization of the passage?A. A hypothesis is introduced, evidence supporting it is presented, and a call for further research to strengthen the hypothesis is made.
B. A phenomenon is described, a prediction about its effects is made, and then evidence contradicting the prediction is analyzed.
C. Two competing explanations for a phenomenon are proposed, and one is shown to be more plausible based on empirical data.
D. A theory is described, and an example that aligns with the theory’s predictions is explored in detail.
E. A phenomenon is introduced, an exception to its typical outcome is explained, and a refined hypothesis accounting for the exception is proposed.
A) Incorrect: The passage does not focus on evidence supporting the initial hypothesis. Instead, it highlights an exception that leads to a refinement of the hypothesis.
B) Incorrect: While the passage discusses a contradiction, the emphasis is not solely on the prediction being disproven, but on modifying the hypothesis to explain the anomaly.
C) Incorrect: The passage does not present two competing explanations but rather a single hypothesis that is adjusted based on new observations.
D) Incorrect: The passage centers on an exception to the theory (Eyjafjallajökull) rather than confirming it with supportive evidence.[color=#008e02]
E) Correct:[/color]
The passage introduces volcanic forcing (the phenomenon), explains how it typically affects global temperatures, presents Eyjafjallajökull as an exception, and concludes with a refined hypothesis addressing why this eruption did not have the expected cooling effect.
4. The passage provides information to support which of the following statements about the role of stratospheric winds in volcanic forcing?A. Stratospheric winds are more likely to distribute aerosols globally if the volcanic eruption occurs at higher latitudes.
B. The effect of stratospheric winds on aerosol distribution is likely less significant following eruptions that release sulfur dioxide (SO2) at lower altitudes.
C. Stratospheric winds primarily influence the speed at which sulfur dioxide (SO2) from eruptions dissipates rather than its geographic spread.
D. Stratospheric winds are less effective at distributing aerosols when sulfur dioxide (SO2) is released at lower altitudes, regardless of latitude.
E. Stratospheric winds are responsible for preventing the formation of aerosols from sulfur dioxide (SO2) released at low altitudes.
A) Incorrect: The passage clearly states that high-latitude eruptions tend to release SO2 at lower altitudes, limiting global distribution by stratospheric winds. This misrepresents the relationship between latitude and aerosol spread.
B) Correct: The passage emphasizes that when SO2 is released at lower altitudes, aerosols dissipate quickly and do not contribute to significant long-term global cooling, demonstrating that the role of stratospheric winds is diminished.
C) Incorrect: The passage highlights that stratospheric winds affect the distribution of aerosols, not the speed at which they dissipate. This misrepresents the core function of these winds.
D) Incorrect: This option generalizes the impact of lower-altitude SO2 release across all latitudes, while the passage specifically contrasts high-latitude eruptions with tropical ones.
E) Incorrect: The passage does not state that stratospheric winds prevent aerosol formation. Instead, it indicates that lower-altitude SO2 release results in limited aerosol formation, regardless of wind patterns.