1.
_________best describes the process of understanding climate change
Correct Answer
A. Observations interpretation prediction
Explanation
Understanding climate change involves a three-step process. First, observations are made to gather data on various aspects of the climate system, such as temperature, precipitation, and greenhouse gas concentrations. These observations provide a foundation of empirical evidence. Second, interpretation is necessary to analyze and make sense of the observed data. This involves identifying patterns, trends, and relationships within the data and determining their significance. Finally, prediction involves using the observed data and interpreted patterns to make projections about future climate conditions and potential impacts. Therefore, the correct order for the process of understanding climate change is observations, interpretation, and prediction.
2.
Warmer climate -> more evaporation -> more water vapor -> greenhouse effect; this process is a ___ feedback leading to ___ climate
Correct Answer
A. Positive and warmer
Explanation
As the climate becomes warmer, it leads to increased evaporation of water. This increased evaporation results in more water vapor in the atmosphere, which enhances the greenhouse effect. The greenhouse effect then traps more heat in the atmosphere, further contributing to a warmer climate. This feedback loop is known as a positive feedback, as each step reinforces and amplifies the initial warming trend. Therefore, the correct answer is positive and warmer.
3.
Over 100 Myr time scale, the most important source of atmospheric C02 is _____
Correct Answer
D. Mantle
Explanation
Over a time scale of over 100 million years, the most significant source of atmospheric CO2 is the mantle. The mantle is the layer of the Earth between the crust and the core, and it contains a large amount of carbon in the form of carbonates and other minerals. Through processes like volcanic activity and tectonic plate movement, carbon from the mantle can be released into the atmosphere as CO2. This long-term release of CO2 from the mantle contributes to the overall levels of atmospheric CO2 over millions of years.
4.
For deriving the temperature of the geologic past, there are four basic steps:
i. Establish modern calibration
ii. Calculate paleo-T
iii. Collect fossil data
iv. Cross checking between proxies
What is the correct order for them _______
Correct Answer
C. I, iii, ii, iv
Explanation
The first step in deriving the temperature of the geologic past is to establish a modern calibration. This involves gathering data on current temperature patterns and using it as a reference point. The next step is to collect fossil data, which provides information about past climates. Once the fossil data is collected, the paleo-T (paleo-temperature) can be calculated using various methods and techniques. Finally, cross-checking between proxies is done to ensure the accuracy and reliability of the temperature reconstruction. Therefore, the correct order is i, iii, ii, iv.
5.
Temperature has been ____ in the last 50 Myr
Correct Answer
B. Steadily rising
Explanation
The correct answer is "steadily rising." This means that the temperature has been consistently increasing over the last 50 million years.
6.
______is not one of the main orbital cycles that affect glacial cycles.
Correct Answer
C. Eccentricity
Explanation
The main orbital cycles that affect glacial cycles are precession, tilt, and eccentricity. The solstice, on the other hand, is not an orbital cycle, but rather a point in the Earth's orbit where the tilt of the Earth's axis is at its maximum or minimum. Therefore, the solstice is not one of the main orbital cycles that affect glacial cycles.
7.
Based on the 180 record, the transition between 41 kyr cycle and 100 kyr cycle happened roughly at ______ million years ago
Correct Answer
B. .7-1.2
Explanation
The transition between the 41 kyr cycle and 100 kyr cycle happened roughly between .7 and 1.2 million years ago.
8.
Oxygen minimum zone refers to the water depth where organic matters are ____ and nutrients are _____
Correct Answer
B. Decomposed; taken up
Explanation
The correct answer is "decomposed; taken up". The oxygen minimum zone is a water depth where organic matters are decomposed, meaning they break down into simpler substances. This decomposition process consumes oxygen, resulting in low oxygen levels in this zone. At the same time, nutrients are taken up by organisms present in the zone.
9.
____is the correct order of deep water oxygen level from high to low
Correct Answer
D. Pacific Indian Atlantic
Explanation
The correct order of deep water oxygen level from high to low is Pacific, Indian, Atlantic.
10.
During glacial periods, part of atmospheric carbon was stored in____
Correct Answer
B. Ocean
Explanation
During glacial periods, part of atmospheric carbon was stored in the ocean. This is because colder temperatures during glacial periods caused the oceans to absorb more carbon dioxide from the atmosphere. The increased solubility of carbon dioxide in cold water allowed the ocean to act as a carbon sink, effectively storing carbon and reducing its concentration in the atmosphere. This process helped to regulate the Earth's climate by removing carbon dioxide, a greenhouse gas, from the atmosphere and reducing its warming effect.
11.
LGM refers to a period of ____
Correct Answer
A. Most recent strong glaciation
Explanation
The term LGM refers to the Last Glacial Maximum, which was the most recent period of strong glaciation. During this time, large parts of the Earth were covered in ice sheets and glaciers, resulting in a significant drop in global temperatures. The LGM occurred approximately 20,000 years ago and marked the peak of the last ice age.
12.
LGM was approximately _____ kyr ago
Correct Answer
A. 20
Explanation
LGM refers to the Last Glacial Maximum, which was a period of maximum extent of ice sheets and glaciers during the last ice age. The question is asking for the approximate time in thousands of years ago when the LGM occurred. The correct answer is 20, indicating that the Last Glacial Maximum was approximately 20,000 years ago.
13.
Summer insolation during LGM is ____ today’s
Correct Answer
C. Similar to
Explanation
During the Last Glacial Maximum (LGM), which occurred around 20,000 years ago, the Earth experienced a significant cooling period with extensive ice sheets covering large parts of the planet. Despite the overall colder climate, the distribution of solar radiation or insolation during the summer season was found to be similar to today's levels. This suggests that while the average temperature was lower during LGM, the amount of solar radiation received during the summer months was comparable to present-day conditions.
14.
According to CLIMAP reconstruction, global sea surface temperature (SST) during LGM was generally ____ than today’s SST in most ocean basins, except for large areas
Correct Answer
A. Higher; Atlantic
Explanation
According to the CLIMAP reconstruction, the global sea surface temperature (SST) during the Last Glacial Maximum (LGM) was generally higher than today's SST in most ocean basins, except for the Atlantic.
15.
Canada was covered by _____ ice sheet during LGM
Correct Answer
B. Laurentide
Explanation
During the Last Glacial Maximum (LGM), Canada was covered by the Laurentide ice sheet. The Laurentide ice sheet was the largest ice mass during the LGM and extended across much of North America, including most of Canada and parts of the northern United States. It was formed by the accumulation of snow over thousands of years, which gradually compressed into ice. The Laurentide ice sheet played a significant role in shaping the landscape of Canada, leaving behind glacial landforms such as moraines, eskers, and drumlins.
16.
In the figure on the left, darker color shows the temperature and precipitation range for higher spruce population. The figure on right indicates that this core likely recorded _____ conditions from 13 to 10 kyr.
Correct Answer
C. Colder and dryer
Explanation
The figure on the left shows that the darker color represents higher spruce population, indicating that spruce trees thrive in colder and dryer conditions. Therefore, it can be inferred that the core likely recorded colder and dryer conditions from 13 to 10 kyr.
17.
Figure on the right shows that recent alkenone-based tropical sea surface temperature for LGM are lower than the CLIMAP estimates. It somewhat explains the debate of warm tropics by indicating that______
Correct Answer
C. Temperature fluctuation is bigger in tropics
Explanation
The figure on the right shows that the recent alkenone-based tropical sea surface temperature for the Last Glacial Maximum (LGM) is lower than the estimates provided by CLIMAP. This suggests that there is a larger temperature fluctuation in the tropics, which could explain the debate about warm tropics. The fact that the alkenone-based data shows lower temperatures than the CLIMAP estimates implies that there may be significant variations in temperature in the tropical regions, leading to the debate about the warmth of the tropics.
18.
The history of N. American ice sheet retreat was revealed by radiocarbon dating of _
Correct Answer
B. Lake sediments
Explanation
Lake sediments can provide valuable information about the history of N. American ice sheet retreat because they contain organic material that can be radiocarbon dated. By analyzing the age of the organic material in the sediments, scientists can determine when the ice sheet retreated and the lake formed. This information helps to reconstruct the timeline of ice sheet retreat and understand the patterns and processes involved in the changing climate of North America.
19.
Sea level curve on the right shows that the speed of glacial melting was highest at ___ years ago among
Correct Answer
A. 3k
Explanation
The sea level curve on the right indicates that the speed of glacial melting was highest at 3k years ago. This can be inferred from the fact that the sea level curve shows a peak at 3k years ago, suggesting a rapid rise in sea levels due to glacial melting during that time period. The curve gradually decreases after 3k years ago, indicating a decrease in the speed of glacial melting.
20.
Summer insolation was highest around 10ka (since LGM) but rapid sea level rise started before that time because ____
Correct Answer
A. Ice-sheet response can pre-date insolation
Explanation
The correct answer is "ice-sheet response can pre-date insolation." This means that the melting of the ice sheet can begin before the increase in summer insolation around 10ka. This suggests that other factors, such as changes in ocean circulation or atmospheric conditions, could have influenced the melting of the ice sheet before the peak in insolation.
21.
Two pulses were found for global-average ice-sheet melting rate based on____
Correct Answer
A. C14 dated sea level curve
Explanation
The correct answer is C14 dated sea level curve. This is because C14 dating is a method used to determine the age of organic materials, including sea level curves. By analyzing the C14 levels in these materials, scientists can estimate the melting rate of global-average ice sheets. The other options, U-Th dated sea level curve, 13C of Coral, and 13C of Forams, are not directly related to C14 dating and therefore cannot be used to determine the ice-sheet melting rate.
22.
_____value in foram is a convincing evidence of local meltwater event.
Correct Answer
B. Lighter 018
Explanation
A lighter 018 value in foram is a convincing evidence of a local meltwater event. This is because during a meltwater event, there is an influx of lighter isotopes of oxygen (018) due to the melting of ice. This lighter 018 value is then incorporated into the foram's shell, providing evidence of the event.
23.
Paleoceanographer Wally Brocker proposed that meltwater from the N.American ice sheet drained into N. Atlantic and stopped the thermohaline circulation during ____
Correct Answer
A. Younger Dryas
Explanation
During the Younger Dryas period, there was a sudden and significant cooling of the Earth's climate. Wally Broecker proposed that this cooling was caused by the influx of meltwater from the North American ice sheet into the North Atlantic. This influx of freshwater disrupted the thermohaline circulation, which is the global oceanic circulation system driven by differences in temperature and salinity. The disruption of this circulation system resulted in a decrease in the transport of heat from the equator to the poles, leading to the cooling of the climate during the Younger Dryas.
24.
The leading hypothesis to explain millennial oscillations in high resolution ice-core records is ____
Correct Answer
D. Greenhouse gas oscillation
Explanation
The leading hypothesis to explain millennial oscillations in high resolution ice-core records is greenhouse gas oscillation. This suggests that changes in greenhouse gas concentrations, such as carbon dioxide and methane, play a significant role in driving these oscillations. As greenhouse gases increase, they trap more heat in the atmosphere, leading to warming. This warming can then cause ice sheets to melt, which can further impact climate patterns. The oscillations observed in ice-core records are believed to be a result of these complex interactions between greenhouse gases, ice-sheet melting, and climate.
25.
____hypothesis states that long-term drying of Africa turned rain forests into grass lands, influencing early human evolution. The evidence comes from C13 changes that were related to the shift from ____ vegetation.
Correct Answer
A. Savanna; C3 to C4
Explanation
The correct answer is Savanna; C3 to C4. This is because the hypothesis suggests that long-term drying of Africa transformed rainforests into grasslands, which influenced early human evolution. The evidence for this hypothesis comes from C13 changes, which are related to the shift from C3 vegetation (typical of rainforests) to C4 vegetation (typical of grasslands).
26.
The reversal in CO2 and CH4 trends around 8-5 ka is related to _____
Correct Answer
B. Agriculture
Explanation
The reversal in CO2 and CH4 trends around 8-5 ka is related to agriculture. This is because the development of agriculture during this time period led to an increase in human population and the expansion of farming practices. These practices, such as deforestation and the use of fire for land clearance, resulted in the release of carbon dioxide and methane into the atmosphere. Therefore, the increase in greenhouse gas emissions from agricultural activities caused the reversal in the trends of CO2 and CH4 during this period.
27.
The collapse of Tang Dynasty and Mongol empire in China coincided with ____
Correct Answer
B. Weak monsoon
Explanation
The collapse of the Tang Dynasty and Mongol empire in China coincided with weak monsoon. Weak monsoon refers to a decrease in the intensity or duration of the monsoon season, which can lead to reduced rainfall and drought conditions. This could have had a significant impact on agriculture, causing crop failures and food shortages, ultimately contributing to the downfall of these empires.
28.
The disappearing of Mayan was suggested to be related to ____ by climatologist
Correct Answer
B. Drought
Explanation
The correct answer is drought. The disappearance of the Mayan civilization is believed to be linked to a prolonged period of drought. Climatologists have found evidence of a severe and extended dry spell during the time when the Mayan civilization collapsed. This drought would have caused crop failures, water shortages, and ultimately led to societal collapse. The lack of rainfall would have had a devastating impact on agriculture, which was the main source of sustenance for the Mayans. As a result, the Mayans were forced to abandon their cities and disperse in search of more favorable conditions.
29.
Lichens on Canadian Baffin island were killed during Little Ice Age due to the lack of
Correct Answer
C. Sunlight
Explanation
During the Little Ice Age, lichens on Canadian Baffin Island were killed due to the lack of sunlight. Lichens are symbiotic organisms that require sunlight for photosynthesis, which is their primary source of energy. The reduced sunlight during the Little Ice Age would have limited the ability of lichens to produce food, leading to their death. This lack of sunlight would have had a significant impact on the survival and growth of lichens in the region.
30.
This record of Medieval Warm Period and Little Ice Age was obtained____
Correct Answer
C. At high latitude N. hemispHere
Explanation
The correct answer is at high latitude N. hemisphere. The Medieval Warm Period and Little Ice Age were two distinct climatic periods that occurred during the Middle Ages. This record was obtained at high latitude in the Northern Hemisphere, which means it refers to the regions closer to the North Pole. This is significant because it suggests that the climate changes during these periods were more pronounced in the northern parts of the world.
31.
Tree rings are very useful climate records for many reasons but ___ is not one of them
Correct Answer
B. Widely available
Explanation
Tree rings are very useful climate records for many reasons because they provide precise age control, are easy to sample, and have a long record. However, their availability is not one of the reasons why tree rings are useful as climate records.
32.
____does not describe typical El Nino conditions in tropical Pacific ocean
Correct Answer
A. Unusual air circulation pattern
Explanation
The unusual air circulation pattern is the correct answer because it does not describe typical El Nino conditions in the tropical Pacific ocean. During El Nino, there is a reversal in the trade winds, resulting in a weakening or even a reversal of the normal east-to-west winds. This leads to changes in the atmospheric pressure patterns and a disruption of the typical air circulation in the region. The other options, such as less rainfall in eastern Pacific, warming of surface water, and weakened upwelling in eastern Pacific, are all characteristic of El Nino conditions.
33.
El nino was more frequent at ______, among the following time periods
Correct Answer
D. 1800-1900
Explanation
During the time period of 1800-1900, El Nino events were more frequent compared to the other time periods listed.
34.
____is not one of the effects of warming since 1800.
Correct Answer
D. Stopping of thermohaline circulation
Explanation
The melting of mountain glaciers and sea-ice, frequent El Nino events, and frequent droughts and stronger tropical storms are all known effects of warming since 1800. However, the stopping of thermohaline circulation is not one of these effects. Thermohaline circulation refers to the global ocean currents driven by temperature and salinity differences. While climate change can affect ocean circulation patterns, there is currently no evidence to suggest that it has caused a complete stoppage of thermohaline circulation.
35.
___signals of the air clearly indicate the rising CO2 is caused by fossil fuel burning
Correct Answer
B. Radioactivity and d18O
Explanation
The correct answer is "radioactivity and d18O". This is because d18O is a stable isotope of oxygen that can provide information about past climate conditions, including the presence of CO2 from fossil fuel burning. Radioactivity can also be used as a tracer to determine the source of CO2 emissions, as certain isotopes are associated with specific processes such as nuclear power generation. Therefore, the combination of radioactivity and d18O can provide clear signals indicating the rising CO2 levels caused by fossil fuel burning.
36.
A comparison of temperature patterns within the atmosphere between the observation and the model calculations clearly indicate that ____ is the cause of most recent
Correct Answer
A. Human
Explanation
The comparison of temperature patterns within the atmosphere between the observation and the model calculations indicates that the cause of the most recent changes is human activity. This is because the term "human" is the only option provided that can be linked to human-induced changes in the atmosphere. The other option, "nature," is more general and does not specifically attribute the changes to human influence. Therefore, the correct answer is "human."
37.
Recent ocean acidification is caused by ____
Correct Answer
B. Fossil fuel burning
Explanation
Ocean acidification refers to the decrease in pH levels of the Earth's oceans, making them more acidic. This process is primarily caused by the increased concentration of carbon dioxide (CO2) in the atmosphere, which is a result of human activities such as burning fossil fuels. When fossil fuels are burned, they release CO2 into the atmosphere, which then gets absorbed by the oceans. This leads to a chemical reaction that increases the acidity of the water, posing a threat to marine life and ecosystems. Therefore, fossil fuel burning is the correct answer for the cause of recent ocean acidification.
38.
pH of normal seawater is around_____
Correct Answer
C. 8
Explanation
The correct answer is 8. Seawater is slightly alkaline, with a pH value of around 8. This is due to the presence of dissolved salts and minerals, such as carbonates and bicarbonates, which act as buffers and help maintain the pH level. A pH of 8 is considered to be within the normal range for seawater and is important for the survival of marine organisms. It is also worth noting that the pH of seawater can vary slightly depending on factors such as location, temperature, and pollution levels.
39.
Due to chemical equilibrium, atmospheric CO2 dissolving in seawater first becomes:
Correct Answer
A. Carbonic acid
Explanation
When atmospheric CO2 dissolves in seawater, it reacts with water to form carbonic acid. This reaction occurs due to chemical equilibrium, where CO2 molecules combine with water molecules to produce carbonic acid. The formation of carbonic acid is the initial step in the process of CO2 dissolution in seawater.
40.
On planet X, most conditions are similar to those on Earth, except that the pH of seawater is around 7. If there was a large scale methane release into the atmosphere, the proportion of carbonate ion would ___ and bicarbonate ion would___.
Correct Answer
A. Increase;decrease
Explanation
If there was a large scale methane release into the atmosphere on planet X, it would lead to an increase in the proportion of carbonate ion. This is because methane reacts with oxygen to form carbon dioxide, which then dissolves in seawater and reacts with water to form carbonic acid. Carbonic acid then dissociates into bicarbonate ion and hydrogen ion, and the bicarbonate ion further dissociates into carbonate ion and hydrogen ion. As a result, the concentration of carbonate ion would increase. On the other hand, the release of methane would also lead to a decrease in the proportion of bicarbonate ion, as it would be consumed in the formation of carbonic acid.
41.
In a higher CO2 world, biological calcification becomes ____ and carbonate dissolution becomes _____
Correct Answer
C. Harder, easier
Explanation
In a higher CO2 world, biological calcification becomes harder because increased CO2 levels lead to ocean acidification, making it more difficult for organisms to form calcium carbonate structures. On the other hand, carbonate dissolution becomes easier as higher CO2 levels increase the acidity of the ocean, causing the dissolution of carbonate minerals.
42.
An example of severe ocean acidification due to rapid C release in geological history is____
Correct Answer
A. Paleocene-Eocene Thermal Maximum
Explanation
The Paleocene-Eocene Thermal Maximum is an example of severe ocean acidification due to rapid carbon release in geological history. During this event, which occurred approximately 55 million years ago, there was a significant increase in atmospheric carbon dioxide levels. This led to a rapid increase in ocean temperatures and a subsequent acidification of the oceans. The acidification had detrimental effects on marine life, causing mass extinctions of various species. Therefore, the Paleocene-Eocene Thermal Maximum is a well-documented example of how rapid carbon release can result in severe ocean acidification.
43.
Tolerance of low oxygen condition in marine animal is _____
Correct Answer
D. Highly variable
Explanation
Marine animals have varying abilities to tolerate low oxygen conditions. Some species have evolved adaptations that allow them to survive in environments with low oxygen levels, while others are more sensitive and cannot tolerate such conditions. Therefore, the tolerance of low oxygen condition in marine animals is highly variable.
44.
____ocean has the largest volume of suboxic water
Correct Answer
D. N Pacific
Explanation
The North Pacific Ocean has the largest volume of suboxic water. Suboxic water refers to areas in the ocean where oxygen levels are extremely low, creating conditions that are unfavorable for most marine life. The North Pacific Ocean has a larger volume of suboxic water compared to the other options listed.
45.
Oxygen utilization in seawater is mostly due to ____
Correct Answer
A. Oxidation of organic matter
Explanation
Oxygen utilization in seawater is mostly due to the oxidation of organic matter. Organic matter in the form of dead plants, animals, and other organic substances undergoes a process called oxidation, where oxygen is consumed. This process is carried out by bacteria and other microorganisms present in the water. They break down the organic matter, releasing energy and consuming oxygen in the process. This is a vital process in marine ecosystems as it helps in the decomposition of organic material and recycling of nutrients.
46.
Shallow hypoxic depth of N Pacific is largely due to ____
Correct Answer
B. Poor ventilation
Explanation
The shallow hypoxic depth of the North Pacific is largely due to poor ventilation. Poor ventilation refers to the limited exchange of oxygen between the surface and deeper waters. This can occur due to factors such as weak winds, stable water column, and low mixing of surface and deep waters. As a result, oxygen levels decrease with depth, leading to hypoxic conditions. Other factors like oxidation of organic matter, dissolution of CO2, and photosynthesis may also contribute to hypoxia, but poor ventilation is the primary reason in the North Pacific.
47.
______is not one of the major control of O2 level beneath the surface ocean
Correct Answer
A. AtmospHeric co2
Explanation
The major controls of O2 level beneath the surface ocean are ventilation, temperature, and oxygen utilization. Atmospheric CO2 does not directly control the O2 levels in the ocean, so it is not considered one of the major controls.
48.
Figure below shows human footprint correlate with recent hypoxic events because of ______pollution
Correct Answer
B. Co2
Explanation
The figure shows that human footprint correlates with recent hypoxic events, meaning that there is a connection between human activities and the occurrence of these events. The question asks for the cause of this correlation, and the correct answer is CO2 pollution. CO2 pollution refers to the release of carbon dioxide into the atmosphere through various human activities, such as burning fossil fuels. This excess CO2 in the atmosphere contributes to global warming and ocean acidification, which in turn can lead to hypoxic events in marine ecosystems.
49.
Strong ocean deoxygenation events in the past left ___ in geological deposits
Correct Answer
B. Organic rich shale
Explanation
Strong ocean deoxygenation events in the past caused an increase in the deposition of organic matter in marine sediments. This organic matter eventually became buried and preserved in geological deposits, specifically in organic rich shale. Shale is a type of sedimentary rock that forms from the compaction of fine-grained sediments, and when it contains a high amount of organic material, it is referred to as organic rich shale. Therefore, it is likely that strong ocean deoxygenation events in the past left organic rich shale in geological deposits.
50.
Glacial-interglacial CO2 fluctuations are roughly between 200 and 280 ppm. The current atmospheric CO2 level is about ___ ppm above the interglacial maximum value.
Correct Answer
C. 100
Explanation
The given information states that glacial-interglacial CO2 fluctuations range from 200 to 280 ppm. The question asks for the current atmospheric CO2 level above the interglacial maximum value. Since the interglacial maximum value is 280 ppm, the current atmospheric CO2 level is 100 ppm above that value.