GLG 335 Quiz Questions
decrease
growth of ice sheets on land corresponds to a ______ in global (eustatic) sea level
negative
sign of the loop on slide 23 is....
warmer & higher
temperatures were ______ and carbonate deposition was _______ during the cretaceous period relative to today.
lower
the higher the salinity of sea water, the ________ the freezing temperature of that water
sediments and rocks
the largest carbon reservoir within the carbon cycle is
high
A side-by-side comparison of the ice-volume record from ocean sediments, and the CO2 record from ice cores reveals that when atmospheric CO2 concentration is low ice volume is
Iridium, Ir
A thin layer of sediment that is enriched in what rare element is found worldwide and dated to the time of the major extinction event approximately 65 Ma? (Hint: it may influence your answer to know that this element is rare on Earth, but much more common in some types of meteorites.)
Forcing
Any process or disturbance that drives changes in climate is referred to as a
risen.....17
After removing local effects from tide gauge records, and including recent satellite-based measurement of sea level, it appears that sea level has ______ roughly _______ cm over the 20th century.
False
Air bubbles in ice cores represent an older atmosphere than the ice surrounding the bubble.
cooling
An increase in the clustering of volcanic eruptions after 1200 AD may have contributed to a small ___________ in the northern hemisphere.
Positive
As an ice sheet grows, its upper surface is moved higher into the atmosphere. The higher the ice sheet surface moves into the atmosphere, the cooler the mean annual air temperature experienced by the ice sheet surface. The cooler the mean annual air temperature, the less ablation experienced by the ice sheet. The smaller the amount of ablation, the more an ice sheet can grow. Together these facts constitute a __________ feedback on ice sheet growth.
Positive
As an ice sheet grows, its upper surface is moved higher into the atmosphere.The higher the ice sheet surface moves into the atmosphere, the cooler the mean annual air temperature experienced by the ice sheet surface.The cooler the mean annual air temperature, the less ablation experienced by the ice sheet.The smaller the amount of ablation, the more an ice sheet can grow.Together these facts constitute a __________ feedback on ice sheet growth.
rose/lost
As deglaciation proceeded, sea level _______, meaning important connections between landmasses were _______.
True
As northern hemisphere insolation begins to increase just after reaching a minimum, northern hemisphere ice volume continues to increase until insolation becomes large enough to cause ablation to exceed accumulation
Laurentide
As part of the CLIMAP reconstruction of the Last Glacial Maximum (LGM) world the "excess ice volume", or ice volume in excess of our present-day ice volume, was partitioned amongst the various ice sheets of that glacial world. Which ice sheet held the largest fraction of the excess ice volume at LGM?
smaller
As was the case in previous interglaciations, millennial climate variability over the last 8 kyrs has been _________ in amplitude than during glaciations.
1. Loess records from southern China 2. North Atlantic sea-surface temperature variations derived from planktonic foraminifera assemblage changes seen in marine sediment cores. 3.Dust in the Greenland Ice Sheet 4.Vegetation changes recorded as pollen assemblage variations in European lake sediments
Beyond benthic foram δ18O (ice volume) and coral reef (sea level) records, what other records indicate a dominant 100-kyr periodicity of climate change over the last 900 thousand years?
True
Both ablation and accumulation depend, to some extent, on mean annual temperature, but ablation is much more sensitive to temperature.
true
CO2 fertilization of tree growth during the time-frame of the instrumental record complicates efforts to extract climate information from tree rings because it mimics improved growth conditions that would otherwise be related to temperature and precipitation.
A. changes in the proximity to the source waters for precipitation landing as snow on the glacier or ice sheet B. changes in air temperature over the ice sheet or glacier glacier or ice sheet. C. changes in the \delta18O of the source waters. E. changes in the elevation of the glacier or ice sheet
Changes in the \deltaδO18 values recorded in ice cores can be produced by
The wind direction over Shideler Hall changes from north to east between 8 and 9 AM.
Climate is a broad composite of the time-averaged (over years or longer) condition of a region, measured by its temperature, amount of rain or snowfall, snow and ice cover, wind direction and strength, and other factors. Which one of the following scenarios does not represent a climate change?
6km
Continental crust has a density that is approximately 80% of the density of the mantle. Knowing this, and treating a block of crust as floating on the mantle:Approximately how much of a 30 km thick block of crust is above the top of the mantle? I.e., what is the so-called freeboard height of the crust?
d18) and dust changes in greenland ice cores
Dansgaard-Oeschger oscillations were first identified in
δ18O dust
Dansgaard/Oeschger events were first identified as millennial-scale variations in what ice-core derived quantities?
warmer, wetter conditions
During El Niño periods, the eastern Pacific tends to experience
cooler temperatures and less rainfall
During La Niña conditions the eastern side of the tropical Pacific Ocean will usually experience
true
During an El Niño period the δ18O of eastern Pacific corals will decrease
False
Earth is closer to the Sun during Aphelion
the tilt of Earth's rotational axis relative to the plane of its orbit around the sun; this produces seasonal changes in the angle at which sunlight arrives on Earth's surface at a particular latitude.
Earth's seasons are primarily produced by
1. the failure of crops in far norther regions of Europe that had previously been successful, due to a shorter growing season 2. areas of dead lichen on Baffin Island which date to the Little Ice Age period 3.more weeks per year of sea ice along the north and west coasts of Iceland 4. historical records of glacier advances in the Alps and the mountains of Norway
Evidence for a cooler climate in areas surrounding the North Atlantic during the Little Ice Age includes
Approx. 4-6ºC
Evidence suggests tropical glaciers and vegetation limits extended some 0.6-1 km lower in elevation at LGM than today. If that elevation drop, relative to today, is purely due to cooler temperature at sea level, how much cooling does it represent? Let's assume that the appropriate lapse rate to apply for the tropics is the wet adiabatic lapse rate of 6.5 ºC/km. Use this lapse rate and the lower LGM glacier and vegetation limits to estimate how much cooler the LGM tropics were relative to today.
false
Times when the Sun has a large number of sunspots correspond to times of reduced solar energy output.
90%
For an iceberg floating in seawater, the density ratio is 920/1028, which is approximately 0.9, or 90%, i.e., the density of ice is roughly 90% that of seawater. Based on this, approximately how much of a floating iceberg's thickness is below the sea surface? Assume we're looking at a so-called tabular iceberg, one whose upper surface and base are fairly flat and horizontal, meaning its thickness is fairly constant across the whole iceberg.
sea-level changes, reflecting ice-sheet volume changes over orbital time scales
Fossil coral reefs provide direct evidence for
100 kyr
From approximately 900 kyr ago to the present, the dominant period of ice-volume variation is:
Yes, the amplitude of ice-volume variation increased circa 900 ka.
From ~2.75 Ma to 900 ka, ice volume varied at a 41 kyr period. Since 900 ka, the dominant period of ice-volume variation was 100 kyr. So the period changed circa 900 ka. Did the amplitude change as well?
more
Global surface temperatures have increased by 0.8-1 ºC since 1900. That includes both sea-surface temperature and land temperature. Would you expect temperature on land to have increase more or less than the global average?
decrease
Growth of ice sheets in the Northern Hemisphere should increase/decrease atmospheric methane
periods of unusually rapid deposition of ice rafted debris in the N. Atlantic Ocean, separated by 7-12 kyrs
Heinrich events are
A.Atmospheric oxygen concentration is declining as carbon-dioxide concentration is increasing, indicating the the carbon dioxide comes from burning of organic carbon, not volcanic degassing of inorganic carbon dioxide. B.Atmospheric carbon dioxide contains a decreasing amount of 13C relative to 12C, indicating a plant-based (not volcanic) source (either modern or fossil organic carbon) C.Atmospheric carbon dioxide contains decreasing amounts of radioactive carbon (14C), indicating a very old (radiocarbon dead) source
How do we know that the recent rise in atmospheric CO2 concentration is primarily due to burning of fossil fuels?
Very quickly, because easily weathered minerals are exposed; over time the rate slows down, as only the more resistant minerals remain.
How quickly after deposition does freshly fragmented (broken up by physical weathering) debris undergo most chemical weathering?
False
Humans are the only animals that use tools.
0.3m
If 1 meter of ice is added on top of the floating crust, by how much is the surface elevation increased?
It would increase the δ13C of the water in the surface ocean.
If the biological pump increases export of organic (12C-enriched) carbon to the deep ocean, from the surface ocean, how would that change the δ13C of the water in the surface ocean.
O2 should decrease
If the rise in atmospheric CO2 concentration since the start of the industrial revolution is due to burning of organic material (wood and fossil fuels), what should we expect to see in terms of atmospheric O2 concentration?
3.9-6.5 ºC 6.5 (0.6-1km) --> estimate range
If tropical glaciers, that today need Tg=-2.5 ºC to survive, were 600-1,000 m (0.6-1 km) lower at LGM, how much tropical cooling would that imply?Assume the wet adiabatic lapse rate applies.
lower and young
If we incorrectly assume that LGM production of 14C is the same as today, when it was in fact higher, then we are in effect assuming that the starting amount of 14C in a LGM sample (an organism that died back then) is _____ than it should be, and thus our resulting age estimate for an LGM sample will be too ______.
False
If you can accurately map the surface and bed elevation of an ice sheet, then you have an accurate measure of the mass of that ice sheet.
raised beaches in formerly glaciated areas
In addressing the sawtoothed character of the ice-volume signal over the last 2.7 Ma, and particularly the last 900 kyrs, we emphasized the role of two positive feedbacks: the ice-albedo feedback, and the CO2-ice feedback. The delayed response of the depressed crust underneath ice sheets to the removal of the ice was also implicated, as it can allow ice sheets to be vulnerable to collapse as sea level begins to rise. What is an indicator of this delayed response of the crust to ice removal?
sea-floor spreading would need to have decreased over the last 50 million years
In order for the BLAG, or sea-floor spreading, hypothesis to be a candidate in explaining the gradual global cooling over the last 50 million years, what would need to happen?
an increase in silicate weathering in conjunction with an increase in continent to continent collision over the last 50 million years
In order for the uplift-weathering hypothesis to be a candidate in explaining the gradual global cooling over the last 50 million years, what would need to happen?
Falling
In the areas that were formerly covered by ice sheets during the last glacial maximum, local (or relative) sea level is now ______________. (Hint, consider what happens to the Earth's crust after the ice load is removed).
The sign of the weathering-to-atmospheric carbon-dioxide coupling is negative (-) The overall sign of the loop is negative (-)
In the image attached here, which illustrates the "chemical weathering thermostat" feedback, what is the sign of the coupling between weathering and the amount of carbon dioxide in the atmosphere, and what is the overall sign of the feedback loop? (Hint: thermostats tend to stabilize the temperature of a room or a house)
More sensitive during colder times
Is our climate system more sensitive to a change in atmospheric CO2 concentration during colder times or warmer periods? In other words, would a given increase in atmospheric CO2 concentration yield a larger warming during cooler or warmer times?
wetter than today, because of the southward displacement of the jet stream at LGM.
LGM conditions in the american southwest were
downwelling
Looking at the wind direction in the figure below, would the resulting Ekman transport be producing downwelling or upwelling along the coast of California?
anoxic (low oxygen) & lower
Methane production tends to occur in ________ environments such as swamps and other wetland areas. On orbital timescales, the production rate of methane is thought to have been _______ during times of lower insolation.
Summer
Milankovitch theory proposes that higher latitude (polar) insolation changes, produced by orbital variations, drive the growth and decay of ice sheets. For which season are those insolation changes most important, according to the theory?
false
Millennial oscillations are truly cyclic, with a consistent periodicity. T/f?
out of
Millennial variations in d18O seen in Antarctic and Greenland ice cores are ______ phase with each other.
False
Modeling studies suggest that Earth's climate is less sensitive to changes in atmospheric greenhouse gas concentrations during colder (icehouse) times than during warmer (greenhouse) periods.
3.... 1.2...... 1.8
Modeling studies suggest that a doubling of atmospheric CO2 will yield a global warming of ____ºC, with the direct radiative effect producing a warming of __ºC, and feedbacks responsible for the remaining warming of ___ºC.
`
Oak has a density that is approximately 80% of the density of water. Knowing this, how much of a floating oak block would stick up above the above the water surface?
true
One hypothesis for the megafaunal extinctions 15-10 ka is that the climate changes seen during deglaciation created conditions to which the animals could not adapt. One key criticism of this hypothesis is that no similar extinction events had been seen in any of the previous 40+ deglaciations over the last 2.75 Ma.
The farther away the source, the smaller, or more negative, the δ18O values
One of the factors that can change the δ18O of snow falling on a a glacier or ice sheet is the distance of the source, i.e., how far the water vapor had to travel before precipitating and falling. How does increasing source distance impact δ18O of the snow that's falling?
negative
Organic material (made mostly through photosynthesis) tends to have a lower ratio of 13C to 12C than inorganic material. The mean value of d13C of inorganic carbon dissolved in ocean water is 0‰. Therefore the d13C value for organic material is, by comparison,
negative
Organic material (made mostly through photosynthesis) tends to have a lower ratio of 13C to 12C than inorganic material. The mean value of δ13C of inorganic carbon dissolved in ocean water is 0‰. Therefore the δ13C value for organic material is, by comparison,
False
Periods when the Sun has fewer sunspots correspond to times of increased output of solar radiation.
decreased, thicker
Peter Clark suggested that over the repeated glaciations of last 2.75 million years ability of the North American ice sheet to slide over its bed _______________ due to erosion of that bed. The result is that the later versions of this ice sheet were ___________ than the earlier versions.
False
Positive feedbacks in Earth's climate system tend to stabilize the temperature, making the temperature variations smaller than they would otherwise be without those positive feedbacks.
True
Radiocarbon (14C) ages are generally younger than true, or calendar, ages.
false
Radiocarbon, or 14C, would be an excellent isotope to use to date 10-million year old coal deposits
As far back as the 41 kyr period glaciations, before 900 kyr, with the exception of interglacial times
Records from long ocean sediment cores reveal that millennial oscillations have occurred
LGM conditions were cooler and wetter than Holocene conditions, near that lake.
Say a sediment core was collected from a lake in the upper midwest, and that core was then examined by a palynologist (pollen expert). Further, say she found that LGM-aged lake sediments contained predominantly spruce pollen, and that more recent (Holocene) sediment contained mostly prairie (grasses and herbal) pollen. What can you say about the change in conditions near the lake from LGM to Holocene times?
warming and drying
Say that your lake sediments show a shift from mostly spruce pollen to mostly grass and herb pollen as we go from the LGM to the mid—Holocene. What qualitative climate change does that indicate?
It would decrease deepwater formation
Say the northern North Atlantic ocean is suddenly filled with a large number of melting icebergs. How might that impact deepwater formation in the North Atlantic?
The standard 14C age will be younger than calendar
Say we analyze the carbon content of a chunk of wood found in a glacial moraine, and find that it appears to be 3 14C half lives old. Say if I use the standard, but incorrect, 14C half life of 5,568 yrs/half-life, rather than the correct half life of 5,730 yrs/half-life. Will my standard 14C age be younger or older than the correct (calendar) age?
Warming would continue; thermal inertial (delay) in the Earth system, and in particular in the ocean, mean we have only seen a fraction of the total warming we should expect from the anthropogenic rise in greenhouse gas concentrations.
Say we were somehow able to magically stabilize the atmospheric concentrations of all greenhouse gases at today's levels, and kept them at those levels in perpetuity. What would happen to global temperature?
10,000 years
Say we were to suddenly shift into positive mass balance. At best that provides ~0.3 m/yr of ice-equivalent deposition. How long will it take to grow a 3 km thick ice sheet?
6 m/kyr
Say we're looking at fossil reefs in an area of tectonic uplift. In particular let's say we observe that a fossil reef from the last glacial maximum (~20 kyr ago) is now at present day sea level. What is the average rate of tectonic uplift, in m/kyr?
False
Sea level lowering causes glaciation. T/F?
1. the erosive power of mountain glaciers 2. increased mass wasting due to steeper slopes 3. increased water flow because of orographic precipitation
Select all of the ways in which tectonic uplift (mountain building) increases rock fragmentation, and thus weathering.
40%
Since satellite-based measurements of Arctic sea-ice extent began in the 1970s, sea-ice extent has declined by approximately _____%
a trend toward more jagged leaf margins though time
Some of the evidence for the cooling over the last 50 million years comes from changes in leaf morphology (shape). According to this leaf-morphology proxy, as conditions cooled, the fossil leaf record should generally show
negative (cooling)
Sulfate aerosols produced by burning of coal as well as smelting (processing of metal ores) act as a _____ radiative forcing.
280 (pre-industrial) & 405 (present) ppm
The pre-industrial and present-day atmospheric concentrations of carbon dioxide are approximately _____ and _____ ppm, respectively.
The rate of seafloor spreading and thus volcanic degassing of carbon dioxide.
The BLAG hypothesis relies on gradual variations in ________ over time to generate variations in climate, from warm (hothouse) to cool (icehouse).
right
The Coriolis force, produced by the rotation of our planet, tends to deflect moving objects to the ________ in the northern hemisphere.
warmer and more
The Cretaceous period is generally associated with _______ temperature and ______ carbonate sedimentation, relative to today.
Closed
The Earth system is, to good approximation,
Dry
The Lapse Rate is the change in temperature with altitude. Generally speaking, is it bigger in magnitude for dry (unsaturated), or moist (saturated) air?
3
The Stefan-Boltzman Law relates the temperature of a black body and the total amount of radiation that the body is emitting (per square meter of its surface area). More specifically, denoting the energy emitted per square meter as E, the Stefan-Boltzman constant as and the temperature as T, the law is E= T4 Knowing this, to increase the energy output of a black body by factor of 81, by what factor would you need to increase the temperature of that body?
Cooling/North Atlantic
The Younger Dryas was a _______ event that primarily affected the ________ region.
cooling....North Atlantic
The Younger Dryas was a _______ event that primarily affected the ________ region.
faint....weaker.....higher
The ______ young Sun paradox comes from the fact that early in our solar system's history the Sun's energy output was notably _____ than it is today, yet geological evidence suggests that Earth's overall temperature was not significantly different from today's. The presumed solution to the paradox is that the greenhouse gas concentration was ______ earlier in Earth's history than it is today.
False
The ability of the precession of the equinoxes to impact Earth's climate is increased if Earth's orbit is more circular (i.e., less elliptical).
0.3 or 30%
The albedo of Earth today is approximately
1400-1900 AD
The approximate time frame for the Little Ice Age is
No, S.H. climate did not vary on orbital time scales.
The ice-volume variations are thought to be dominated by growth and decay of ice sheets in the Northern Hemisphere. Did the Southern Hemisphere climate respond to what was happening in the Northern Hemisphere?
- Increased cultivation of rice - increased numbers of cattle and other livestock - leakage from natural gas pipelines, in addition to leakage from oil and gas extraction activities (e.g., wells and refineries)
The atmospheric concentration of methane has increased markedly since the early nineteenth century (from 600 to over 1800 ppb). Several human activities have caused this increase, including
redistribution of heat within the atlantic ocean
The bipolar seesaw involves
False, neandertaalhs
The braincase size for modern humans (Homo sapiens) is the largest of all the species in the Homo genus.
Massive deglacial floods from a large proglacial lake (in this case glacial Lake Missoula).
The channeled scablands of eastern Washington and western Idaho were produced by what deglacial process?
local sea level fall
The coastlines along areas formerly covered by ice sheets during LGM are presently experiencing:
false
The degree to which human evolution was influenced by climate change is well constrained by the combination of fossil human remains and proxy records of climate.
rise, agriculture
The early anthropogenic hypothesis attempts to explain an anomalous ______ in greenhouse gas concentration over the last several thousand years as a consequence of early ________.
20 ºC
The formula to convert from temperature in ºF (call it Tf) to temperature in ºC (say Tc) is Tc = (Tf-32) x 5/9 What is the temperature in ºC if you know the temperature is 68ºF?
more
The global average increase in surface temperature is 0.8-1ºC since 1900. That global average includes both land and ocean temperature changes. Given that the land surface is made of rock and soil, which have notably lower heat capacities than water, would you expect temperature on land to have risen more or less than what has been seen globally?
Rice
The growth in which type of agriculture would be a good candidate to explain an increase in atmospheric methane?
more than
The higher heat capacity of water compared to rock or sediment means that for the same seasonal variation in insolation the land temperature will vary ___________ the ocean.
0.8 - 1
The instrumental record of temperature (mostly from meteorological stations, and later satellite observations) indicates a global increase of approximately _____ ºC since the late nineteenth century. The temperature increase on land has been slightly less than double that.
The biological pump
The iron fertilization hypothesis suggests that a reduction in atmospheric CO2 concentration will result from increasing which of the following processes?
the biological, or carbon, pump
The iron fertilization hypothesis suggests that a reduction in atmospheric CO2 concentration will result from increasing which of the following processes?
rising moist air gains warmth from the latent heat of condensation/vaporization for water
The lapse rate (rate of decrease in temperature with altitude) is larger in magnitude for dry (unsaturated) air than for moist (saturated) air because
The concentration of greenhouse gases in Venus's atmosphere is much greater than is the case for Earth.
The main reason Venus is so much hotter than Earth is because
1. that the southern portion of the Laurentide Ice Sheet was underlain by soft, easily deformable sediment that would allow faster flow than the CLIMAP scientists had considered 2. the modeled thickness of ice that is required to produce the observed bedrock rebound history is thinner than the CLIMAP maximum scenario
The main reason(s) that subsequent work to CLIMAP supports thinner North American ice coverage than the CLIMAP maximum scenario is (are)
1. There was extensive glaciation in the Northern Hemisphere, which cooled regional climate and increased Earth's albedo compared to today. 2. Greenhouse gas concentrations were lower than today, weakening the greenhouse effect relative to its modern strength.
The main reason(s) that the Last Glacial Maximum, at approximately 21,000 years ago, was colder than today is (are)
Eccentricity
The measure of how elliptical, rather than circular, the orbit of the planet is around the Sun is called _______, and it varies on an approximately 100 kyr (kyr=1,000 years) timescale, as well as on an approximately 400 kyr timescale.
False
The opening and closing of gateways between oceans provide an excellent explanation for the gradual cooling of Earth over the last 50 million years. t/f?
Positive
The overall sign of the feedback loop illustrated below is: (from previous def)
Glaciations do not always occur when continents are in a polar position.
The polar position hypothesis posits that major glaciations occur when continents are found in within the arctic or antarctic circles. Why is the hypothesis not the accepted explanation for the timing of major glaciations over the last 500 million years?
55% atmosphere, 25-30% surface ocean, 15-20% biosphere
The three main reservoirs receiving the carbon dioxide released by anthropogenic activities are the atmosphere, the shallow ocean, and the biosphere. Over the last several decades, what fraction of the emitted carbon dioxide has ended up in each reservoir?
41 kyr
The tilt (or obliquity) of the Earth's rotational axis relative to the plane of Earth's orbit around the Sun varies on what timescale?
reduces.....cooler
The uplift-weathering hypothesis, proposed by Maureen Raymo and her colleagues, suggests that uplift produced by continental collisions increases weathering and thereby ________ the amount of carbon dioxide in the atmosphere, producing a ________ climate.
Over the oceans & in lower latitudes
The warming since the late 19th century is not evenly distributed over the surface of the planet. Where has the warming been smallest?
-2.5 ºC --> 6.5x5km= 32.5 --> 30-32.5=-2.5
The wet adiabatic lapse rate of Γ=6.5 ºC/km means that tropical glaciers can exist above 5 km elevation today.Today tropical sea-level temperature Tss=30 ºC. What would the temperature (Tg) be at z=5 km elevation?Tg = Tss - z*Γ = ??? ºC
temperature
The δ18O values of the shells of foraminifera found in ocean sediments primarily reflect changes in ice volume and ______?
The rate of production of 14C has varied through time. The process involves 14N being converted to 14C through bombardment by cosmic radiation.
There are two main reasons that radiocarbon (14C based) age is offset from calendar (true) age. One is that the standard half life adopted is slightly shorter than the correct half life for 14C. What is the other main reason?
reduced
Times of major human population decline have been hypothesized to correspond to times of __________ atmospheric CO2 concentration.
The dip, or inclination, of the rock's magnetic minerals
What aspect of the paleomagnetism (fossil magnetic character) of igneous rocks provides an indication of the latitude of the rock when it solidified?
A.~320 ppm B.~280 ppm C.~190 ppm D.~300 ppm E.~400 ppm
What do you think: in our longest ice core record, going back 800,000 years, what's the highest atmospheric CO2 concentration measured prior to the industrial revolution?
Elevation change in tropical-glacier moraines and vegetation zones
What evidence suggests that the CLIMAP estimate of the LGM-to-present tropical temperature change,1-2 ºC, is too small?
Ice cores
What is our best source of data for atmospheric greenhouse gas concentrations going back several hundred thousand years?
Benthic δ13C will decrease
When glaciations begin, some 12C-rich organic carbon that was on land is decomposed (turned into inorganic carbon), and stored in the deep ocean. What qualitative signal in δ13C should we see in the shells of benthic forams as a result of this?
50,000 years
When is the next glaciation? Ignoring anthropogenic climate change, the timing should be guided by insolation changes, per Milankovitch Theory. In particular, a sensible idea is to examine calculations of future insolation at high norther latitudes. It so happens that high northern latitude (65ºN) insolation will not fall significantly below our present-day value until ____ years from now.
true
When using trees to look for climate signals, it is generally better to core trees that are often stressed and living near the environmental limits of their species.
cold ocean
Which can hold more dissolved CO2?
Ocean
Which has absorbed more heat during the 20th-Century warming: the atmosphere or the ocean?
Anoxic - little to no O2 available
Which is the usual environment for methane production in the biosphere?
1. The use of stone tools circa 2.5 million years ago. 2. The branching of the prehuman line into the genus Homo and other forms by around 2 million years ago. 3. The development of large brains in the Homo genus since around 2 million years ago. 4. The initial branching off from primitive apes between 6 and 4 million years ago. 5. The onset of bipedalism approximately 4 million years ago.
Which of the following are critical steps in human evolution (you may select more than one)
An increase in the amount of ice cover leads to a decrease in the fraction of sunlight reflected
Which of the following is not a coupling illustrated in the feedback diagram below? 1. fraction of sun reflected ------O Temperature of planet 2. Temperature of planet -----O amount of ice cover 3. amount of ice cover ------> fraction of sunlight reflected
reduced deep see fan sedimentation 100-80 Ma, relative to today
Which of the following is not a factor which contributed to higher sea levels 100-80 million years ago (Ma), relative to modern sea level?
The isostatic bedrock response to ice loading lags ice volume by several thousand years.
Which of the following is not a hypothesis for the unexpected strength of the 41 kyr response of ice sheets from 2.75-0.9 Ma.
The isostatic bedrock response to ice loading lags ice volume by several thousand year
Which one of the following is not a hypothesis for the unexpected strength of the 41 kyr response of ice sheets from 2.75-0.9 Ma?
ocean sediments
Which one of the following types of records could provide climate information covering tens of millions of years at possibly ten thousand to one hundred thousand years of resolution?
N. Hem. summer coincides with perihelion
Which orbital configuration is not conducive (helpful) for growth of N. Hemisphere ice sheets?
less tilt, high eccentricity, summer solstice during aphelion
Which situation is more likely to produce ice-sheet growth, according to Milankovitch theory?
Trees living near the edge of their tolerance ranges.
Which trees would be better for sources of climate variability
Hydrolysis of silicate rocks
Which type of weathering serves as a sink (loss process) of atmospheric carbon dioxide that, over millions of years, roughly balances the rate of input from volcanic degassing?
1. Greenhouse Gas - Ice Feedback, wherein insolation changes drive ice-sheet response, which in turn creates conditions that control the concentration of greenhouse gasses. In particular a reduction in ice volume and extent allows for higher greenhouse gas concentrations, leading to warmer conditions. 2. Ice - Albedo Feeback, wherein insolation changes drive ice-sheet response, which in turn changes the planetary albedo (reflectivity). In particular, as ice extent decreases, the planetary albedo is reduced, leading to more absorption of solar radiation, yielding warmer conditions.
While most scientists agree that the last deglaciation was driven by an increase in summer insolation, two important positive feedbacks played a role in amplifying that insolation signal. Those two feedbacks are...(choose two)
A delayed uplift of the crust subsequent to the removal of ice, in combination with meltwater supplied by the ice sheets from the north, produced the dynamic (moving) water-filled depressions.
Why did proglacial lakes travel slowly northward, following the retreating ice sheets, during the last deglaciation?
inversely related (if temperature increases, the wavelength of maximum emission decreases)
Wien's law relates the temperature of an black body and the wavelength at which it emits its maximum amount of energy. In particular, the law says that the temperature and wavelength of maximum emission are ______________ related.
it will increase
all other things remain the same, if respiration exceeds photosynthesis, what will happen to atmospheric CO2 concentration?
the CO2 levels will increase
if the planet's surface becomes ice covered and very cold, how would you expect that to impact atmospheric CO2?
new surface temperature would be warmer
if you removed Antarctic ice sheet, resulting in 3km lower surface elevation of the continent, how would that affect the surface temperature?
25
if you started with 200 parent atoms, how many parent atoms do you have left after 3 half lives?
No because the cells beneath the surface are not photosynthetic
say significant amounts of CO2 are seeping into the soil of a forest, to the point where pore spaces that would normally hold are now filled with only CO2. would this make for healthy trees?
water level will go up
say you have a swimming pool with a certain water level. what will happen to that water level if you dumped a bunch of gravel into the pool?
1 million years
typical sedimentation deposition in the middle of the ocean is 2mm/kyr. given that rate, how much time, in millions of years would be represented by a 2 meter long section of sediment core?
continental crust
which is the least dense?
warming
which process will not make a parcel of seawater more dense?
higher elevations tend to be cooler
why are glaciers only found at high elevation in lower latitudes?
there's more land in the NH and thus more deciduous plants in total in this hemisphere
why does the seasonal variation in CO2 follow the tempo of the NH deciduous growth and decay?
it has a much larger greenhouse effect than Earth
why is venus so hot in comparison to earth?
4
your rock sample has 50 parents atoms and 750 atoms. assuming the rock sample formed with all parent and no daughter atoms, how many half lives have elapsed since the sample formed?
decrease
δ18O of coral skeletons responds similarly to δ18O from foraminifera. Thus a warming of waters around a coral reef will be seen as a(n) ________ in coral δ18O.
