GLG Final
The main reason(s) that the Last Glacial Maximum, at approximately 21,000 years ago, was colder than today is (are) (choose one or more answers)...
-Greenhouse gas concentrations were lower than today, weakening the greenhouse effect relative to its modern strength. -There was extensive glaciation in the Northern Hemisphere, which cooled regional climate and increased Earth's albedo compared to today.
The main reason(s) that subsequent work to CLIMAP supports thinner North American ice coverage than the CLIMAP maximum scenario is (are)...
-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 -the modeled thickness of ice that would produce the observed bedrock rebound history is thinner than the CLIMAP maximum scenario
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.
0.8
Approximately how long does it take for Earth to complete one orbit the Sun?
1 year
Describe two ways in which ice-cores are dated:
1.) Counting layers in the uppermost parts 2.) Older layers can be dated through radiometric dating
The speed of plate tectonic motion usually falls in what range?
10 centimeters/year
From approximately 900 kyr ago to the present, the dominant period of ice-volume variation is:
100 kyr
At what period do each of the respective orbital characteristics vary?Eccentricity, Obliquity, Precession
100/41/23 kyr
What is the approximate global birth rate, in births per second?
4
The estimated temperature rise resulting from a three -fold increase in atmospheric CO2 concentration (relative to the pre -industrial level) is ____ ºC
4.5
Since satellite based measurements of Arctic sea ice extent began in the 1970s, sea ice extent has declined by approximately ____ %.
40
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?
55% atmosphere, 25-30% surface ocean, 15-20% biosphere.
Lapse rate: dry / wet
9.8 dry & 6.5 wet C/km
Which of the following are critical steps in human evolution (more than one may be correct)...
-The initial branching off from primitive apes between 6 and 4 million years ago. -The onset of bipedalism approximately 4 million years ago. -The use of stone tools circa 2.5 million years ago -The branching of the prehuman line into the genus Homo and other forms by around 2 million years ago. -The development of large brains in the Homo genus since around 2 million years ago.
What's the approximate ratio of the time it took to create the planet's fossil fuels and the time over which we will have largely consumed them? In other words, how much more quickly are we consuming those resources than they are produced?
1,000,000
The range in speed of plate tectonic motion is such that it will take a plate ___ to ___ years to move 10 centimeters.
1-10 years
Does the uplift process invoked in the uplift weathering hypothesis serve as a climatic forcing or feedback?
Forcing
Which two factors govern the magnitude (size) of the so-called solar constant of a planet?
Solar luminosity & distance of the planet from the Sun
What sign is ice-albedo feedback?
Strong positive
During an El Niño event, sea surface temperatures (SSTs) in the eastern tropical Pacific are _____ than normal?
Warmer
During El Niño periods, the eastern Pacific tends to experience
Warmer, wetter
The Earth system is, to good approximation...
closed
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 impact your answer to know that this element is rare on Earth, but much more common in some types of meteorites.)
iridium, Ir
Air bubbles in ice cores represent a younger atmosphere than the ice surrounding the bubble.
true
LGM conditions in the american southwest were
wetter than today, because of the southward displacement of the jet stream at LGM.
The crust underlying today's oceans is ____ relative to the age of most continental crust
younger
What would happen to the δ18O signal seen in the Gulf of Mexico if the delivery of glacial meltwater were to suddenly stop? Presume nothing else changes.
δ18O would go up
The approximate time frame for the Little Ice Age is
1400-1900 AD
Which of the three isotopes of carbon (12C, 13C, or 14C) is not stable? In other words, which isotope is radioactive?
14C
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= T^4 Knowing this, if the temperature of a blackbody were to double, by what factor would its emitted energy increase?
16
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?
20 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?
20% above
The albedo of the Earth is approx. :
30%
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?
300ppm
The present day and pre-industrial atmospheric concentrations of carbon dioxide are approximately _____ and _____ ppm, respectively.
400 (present-day) and 280 (pre-industrial) ppm
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?
41 kyr
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.
50,000
What is the approximate global human population today?
7.5 billion
According to the Stefan-Boltzman Law (hint: T^4), tripling the temperature of a body will increase the amount of energy it emits by what factor?
81
Fossil leaf morphology can be used as a proxy for temperature change over time. What change should we see in leaf morphology in association with global cooling?
A trend toward more jagged leaf margins.
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
A. increased cultivation of rice B. increased numbers of cattle and other livestock C. leakage from natural gas pipelines, as well as leakage from oil and gas extraction activities (e.g., wells and refineries).
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?
All of the above choices are correct: a) Dust in the Greenland Ice Sheet b) Loess records from southern China c) Vegetation changes recorded as pollen assemblage variations in European lake sediments d) North Atlantic sea-surface temperature variations derived from planktonic foraminifera assemblage changes seen in marine sediment cores
Evidence for a cooler climate in areas surrounding the North Atlantic during the Little Ice Age includes
All of the above: A.more weeks per year of sea ice along the north and west coasts of Iceland. B.areas of dead lichen on Baffin Island which date to the Little Ice Age period C.historical records of glacier advances in the Alps and the mountains of Norway. D.the failure of crops in far norther regions of Europe that had previously been successful, due to a shorter growing season
Select all of the ways in which tectonic uplift (mountain building) increases rock fragmentation, and thus weathering.
All of the above: a) increased water flow because of orographic precipitation b) increased mass wasting due to steeper slopes c) the erosive power of mountain glaciers.
What was Maurine Raymo's "smoking gun", i.e., line of evidence, that she interpreted as indicating an increase in chemical weathering following the uplift of the Himalaya and the Tibetan Plateau?
An increase in 87Sr relative to 86Sr in marine carbonates
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.
Anoxic (low oxygen) and lower
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.
Approx. 4-6ºC
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?
Benthic δ13C will decrease
Which can hold more dissolved CO2?
Cold ocean
During La Niña conditions the eastern side of the tropical Pacific Ocean will usually experience
Cooler temps less rainful
An increase in the clustering of volcanic eruptions after 1200 AD may have contributed to a small ___________ in the northern hemisphere.
Cooling
Which of the following would decrease albedo?
Cover the planet in black asphalt
Lithospheric, or tectonic plates, are made up of:
Crust and the outmost, coolest mantle
δ18O of coral skeletons responds similarly to δ18O from foraminifera. Thus a warmingof waters around a coral reef will be seen as a(n) ________ in coral δ18O.
Decrease
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.
Decreased, thicker
The Lapse Rate is the change in temperature with altitude. Generally speaking, is it bigger in magnitude for dry (unsaturated), or moist (saturated) air?
Dry
Earth and the Sun have different peak wavelengths of electromagnetic radiation (EMR) emission. Those respective wavelengths fall into which bands of the EMR spectrum?
Earth: Visible Sun: Infrared
What evidence suggests that the CLIMAP estimate of the LGM-to-present tropical temperature change,1-2 ºC, is too small?
Elevation change in tropical-glacier moraines and vegetation zones
What is the name of the rock fragment, typically large, that is transported and deposited by a glacier?
Erratic
Areas that were formerly covered by ice sheets during the last glacial maximum are now experiencing ___ local (or relative) sea level.
Falling
Global sea-level change is thought to be a driver (forcing) of changes in global climate (T/F)
False
Humans are the only animals that use tools.
False
Periods when the Sun has fewer sunspots correspond to times of increased output of solar radiation.
False
Polaris has always been the Northern Hemisphere navigational star
False
The braincase size for modern humans (Homo sapiens) is the largest of all the species in the Homo genus.
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.
False
The polar position hypothesis posits that major glaciations occur when continents are found 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?
Glaciations do not always occur when continents are in a polar position
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)
Greenhouse Gas- Ice Feedback and Ice- Albedo Feedback
Why is it that at lower latitudes we only find glaciers at higher elevation?
Higher elevations tend to be cooler
What is our best source of data for atmospheric greenhouse gas concentrations going back several hundred thousand years?
Ice cores
The greenhouse effect of Earth's atmosphere causes Earth's surface temperature to be warmer than it would otherwise be due to:
Incoming shortwave radiation is transmitted by the atmosphere but outgoing longwave radiation is partially absorbed by gases in the atmosphere.
Where did most of the extra CO2 from Earth's early atmosphere go?
It is stored as limestone and other carbon-containing rocks in the geosphere.
Approx. 1/3 of the CO2 in the pre-industrial interglacial atmosphere (180 gtons) was missing during glacial times. Where did it go?
It was stored in the oceans as dissolved CO2 It was stored as organic matter in the deep ocean
As more and more CO2 dissolves into our oceans, what will happen to the pH of the ocean water?
It will decrease
All other things remaining the same, if respiration exceeds photosynthesis, what will happen to the atmospheric CO2 concentration?
It will increase
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?
It would decrease deepwater formation.
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.
It would increase the δ13C of the water in the surface ocean.
Which of the two extreme solstice positions yields a stronger seasonality* for the northern hemisphere?
June @ perihelon
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 pollen. What can you say about the change in conditions near the lake from LGM to Holocene times?
LGM conditions were cooler and wetter than Holocene conditions, near that lake.
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?
Laurentide
The role of insolation: which would provide the best situation for growing ice?
Less summer insolation, cold summer
The channeled scablands of eastern Washington and western Idaho were produced by what deglacial process?
Massive deglacial floods from a large proglacial lake (in this case glacial Lake Missoula).
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?
More
What do you think: 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 CO 2 concentration yield a larger warming during cooler or warmer times?
More sensitive during colder times
Which orbital configuration is not conducive (helpful) for growth of N. Hemisphere ice sheets?
N. Hem. summer coincides with perihelion
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,
Negative
Sulfate aerosols put into the atmosphere by burning of coal as well as smelting (processing of metal ores) act as a _____ radiative forcing.
Negative (cooling)
Are we in La Niña, El Niño, or neutral conditions?
Neutral
Which process below generates the energy our planet ultimately recieves from the Sun in the form of electromagnetic radiation>
Nuclear fission
If the rise in atmospheric CO 2 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?
O2 should decrease
A measure of the angle of the title of Earth's rotational axis with the plane described by the planet's orbit around the Sun is called
Obliquity
Which has absorbed more heat during the 20th Century warming: the atmosphere or the ocean?
Ocean
What is the term commonly used to describe the following biochemical reaction?CO2 + H20 + sunlight 0>> sugar + 02
Photosynthesis
What is our navigational star in the Northern Hemisphere?
Polaris
Describe how and why proglacial lakes travel slowly across the landscape behind melting ice sheets:
Proglacial lakes develop in bedrock depressions left by melting ice sheets. They fill in when the bedrock is depressed, and then disappear when the bedrock rebounds, thereby following the massive ice sheets.
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?
Reduced deep-sea fan sedimentation back then
The growth in which type of agriculture would be a good candidate to explain an increase in atmospheric methane?
Rice
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.
Risen, 17
Tree rings are useful in recording climate changes because those changes are reflected in the thickness and other properties (e.g., density and color) of the annual growth rings. When using trees to look for climate signals, is it better to use trees that are very healthy and living well within the environmental limits of their species, or trees that are often stressed and living near the environmental limits of their species?
Stressed trees living near their limits because they will be more susceptible to change
When the Northern Hemisphere is experiencing weaker seasonality due to precession, the Southern Hemisphere is experiencing:
Stronger seasonality
d18O records derived from coral reefs provide proxy evidence for changes in what two variables, and primarily for areas in what part of the ocean?
Temperature and salinity in surface waters of low latitude (mostly tropical) oceans.
The three main orbital characteristics, precession, obliquity, and eccentricity, do indeed change over time. Broadly speaking, on what time scale do these orbital characteristics vary?
Tens of thousands to hundreds of thousands of years
What are the key ingredients that produce both the Ekman spiral and transport?
The Coriolis force, winds blowing on the sea surface, and the friction within the water
The iron fertilization hypothesis suggests that a reduction in atmospheric CO2 concentration will result from increasing which of the following processes?
The biological pump
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?
The farther away the source, the smaller, or more negative, the δ18O values
Periods of time when sea-level was higher are referred to as ____ while those periods when sea-level was lower are called ____
The high stands are called transgressions, the low stands are regressions
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 years.
Say you could magically and instantly remove the Antarctic ice sheet, resulting in a roughly 3 km lower surface elevation of that continent. Considering only the lapse rate in the lowest layer of the atmosphere, how would that 3 km lowering in elevation effect the surface temperature?
The new surface temperature would be warmer
In order for the BLAG, or sea-floor spreading, hypothesis to play a role in the gradual global cooling over the last 50 million years, what should have happened over this time period?
The rate of sea-floor spreading should have decreased
The BLAG hypothesis relies on gradual variations in _____ over time to drive variations in climate, from warm (hothouse) to cool (icehouse).
The rate of seafloor spreading and thus volcanic degassing of carbon dioxide
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)
The sign of the weathering-to-atmospheric carbon-dioxide coupling is negative (-). The overall sign of the loop is negative (-)
Why is it that solar variability associated with sunspots is not considered a major driver of the climate changes seen over the last millennium?
The size of the variation in solar energy output associated with sunspot changes is simply too small to account for a significant change in climate.
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?
The standard 14C age will be younger than calendar
There are two main reasons that radiocarbon (14C based) age is offset from calendar (true) age. One is that the rate of production of 14C has varied through time. The process involves 14N being converted to 14C through bombardment by cosmic radiation. What is the other main reason?
The standard half life adopted is slightly shorter than the correct half life for 14C
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?
The wind direction over Culler Hall changes from north to east between 8 and 9 AM.
Which trees would be better for sources of climate variability
Trees living near the edge of their tolerance ranges
Which is the layer that we mostly live in and where weather occurs?
Troposphere
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.
True
It is at times when Earth's orbit is more elliptical (less circular) that procession of the equinoxes most impact on the planet's seasonality: T/F
True
Modeling studies suggest that Earth's climate is more sensitive to changes in atmospheric greenhouse gas concentrations during colder (icehouse) times than during warmer (greenhouse) periods.
True
Perihelion is when you're closer to the sun T/F
True
Venus is warmer than Earth primarily because...
Venus has a denser atmosphere which is composed almost entirely (96%) of CO2, in contrast to Earth's atmosphere, where CO2 is a trace gas
How soon after deposition does freshly fragmented debris undergo most chemical weathering?
Very quickly, because easily weathered minerals are exposed; over time the rate slows down, as only the more resistant minerals remain.
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?
Warming would continue; thermal inertial (delay) in the Earth system, and in particular the ocean, mean we have only seen a fraction of the total warming we should expect from the anthropogenic rise in greenhouse gas concentrations.
Why does the size of a growing or melting ice sheet lag well behind changes in insolation?
When insolation turns from its minimum andd starts to increase, the glaciers still continue to grow. The effects of insolation rising will not affect the ice sheets for thousands of years.
The abundance of free oxygen (O2) in our atmosphere today is a result of
a rapid increase in photosynthesis on land roughly 500 million years ago.
Describe at least one line of evidence besides changes in benthic foraminiferal O18 that indicates a long term cooling trend over the last 50 million years
animal + leaf fossils
The d18O values recorded in ice cores can change because of
changes in air temperature over the ice sheet or glacier changes in the proximity to the source waters for precipitation landing as snow on the glacier or ice sheet. changes in the d18O of the source waters. ALL OF THE ABOVE
Ocean-continent collision involves an ocean-crust capped lithospheric plate colliding with a continental- crust capped lithospheric plate. Continent-continent collision, on the other hand, involves two continental- crust capped lithospheric plates colliding. Which type of collision does not typically result in volcanic activity?
continent-continent
Which crust/layer is the least dense?
continental crust
Evidence for tropical glaciers and mountain vegetation limits having been 0.6-1 km lower at LGM relative to today suggests either _____ tropical temperatures at LGM, a _____ tropical atmosphere at LGM, or some combination thereof.
cooler & dryer
The Younger Dryas was a _______ event that primarily affected the ________ region.
cooling/ North Atlantic
Dansgaard-Oeschger oscillations were first identified in
d18O and dust changes in Greenland ice cores
A decrease in perennial sea-ice cover will, in and of itself, produce an _____ in planetary albedo?
decrease
During an El Niño period the d18O of eastern Pacific corals will...
decrease (become more negative or less positive)
How would the chemical weathering thermostat respond to a reduction in the input of CO2 from seafloor spreading?
decrease silicate weathering
As salinity of seawater increases, the temperature at which would freeze:
decreases
What is the name of the type of ocean circulation which relies on temperature and salinity differences, and governs the circulation of the deep ocean?
deep (thermohaline) circulation
Positive feedbacks in the Earth's climate system tend to:
destabilize
Say there is a north wind blowing off of east Greenland, would upwelling or downwelling occur? (In NH)
downwelling
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.
eccentricity
The primary energy source driving our Earth's ecosystems and climate system is:
electromagnetic radiation arriving from the Sun
An overall feedback loop is positive if there's an _____ number of _____ couplings.
even; negative
An overall feedback loop is negative if there's an _____ number of _____ couplings.
even; positive
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 today is ____ than it was earlier in Earth's history.
faint/weaker/lower
Earth is closer to the Sun during Aphelion
false
Ice sheets tend to be enriched in d18O relative to ocean water.
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.
false
Millennial oscillations are truly cyclic, with a consistent periodicity.
false
Negative feedbacks in Earth's climate system tend to destabilize the temperature, making the temperature variations larger than they would otherwise be without those negative feedbacks.
false
Sea-level lowering causes glaciation.
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).
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.
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.
false
Volcanic input of CO2 into Earth's atmosphere is a strong candidate for the thermostat regulating climate.
false
Any process or disturbance that drives changes in climate is referred to as a...
forcing
Mercury orbits the Sun at a distance of 58 x 10^6 km, while Earth orbits at a distance of 150 x 10^6 km. Is the solar constant (a.k.a. solar flux density) of Mercury lower than, higher than, or the same as that of Earth?
higher
Anthropocene def:
humans are causing significant changes to the planet
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?
hydrolysis of silicate rocks
The d18O values of the shells of foraminifera found in ocean sediments primarily reflect changes in ocean temperature and
ice volume
All other things being unchanged, the rate of chemical weathering tends to_______ with increasing temperature and moisture.
increase
The magnetic inclination is the angle of the magnetic field relative to a horizontal plane at the surface of the Earth. An inclination of 90º would indicate the field lines are perfectly vertical. An inclination of 0º corresponds to horizontal field lines.Say I were to drive from here to Saginaw, Michigan, about 4º due north. Would the magnetic inclination increase or decrease?
increase
To represent an increase in the greenhouse effect due to increasing concentrations of greenhouse gases in the atmosphere, you would need to -
increase the emissivity
The Monterey hypothesis suggests that the rapid cooling seen approx. 13 million years ago was produced by a temporary ____ in the burial of organic carbon in the shallow continental margins of the Pacific Ocean:
increased
The Snowball Earth hypothesis addresses cold periods that are thought to have involved extensive glaciation and sea-ice cover. Evidence suggests that immediately after these cold. snowball periods, marine carbonate deposition:
increased a lot
Wien's Law: temperature and wavelength are _____ related
inversely
The solar constant for a planet goes _____ with the square of its distance from the Sun, because the solar energy is _____.
inversely; spreading out
The Coriolis force, produced by the rotation of our planet, tends to deflect moving objects to the ________ in the southern hemisphere.
left
Consider evaporation of water (H2O) from the surface of the ocean into the atmosphere. A water molecule whose oxygen atom is 18O will evaporate _____ readily than a water molecule whose oxygen atom is16O
less
Which situation is more likely to produce ice-sheet growth, according to Milankovitch theory? (3 factors)
less obliquity, high eccentricity, summer solstice during aphelion
The higher heat capacity of water compared to rock or sediment means that for the same seasonal variation in insolation the ocean temperature will vary ___________ land.
less than
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 high... ice volume is ______
low
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 ______.
lower & younger
What aspect of the paleomagnetism (fossil magnetic character) of igneous rocks provides an indication of the latitude of the rock when it solidified?
magnetic inclination
Which type of feedback, positive or negative, tend to stabilize the system?
negative
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?
ocean sediments
Millennial variations in d18O seen in Antarctic and Greenland ice cores are ______ phase with each other.
out of
Heinrich events are...
periods of unusually rapid deposition of ice rafted debris in the N. Atlantic Ocean, separated by 7-12 kyrs
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
What is a proxy indicator of the delayed response of the crust to ice removal?
raised beaches in formerly glaciated areas
The bipolar seesaw involves
redistribution of heat within the atlantic ocean
Times of major human population decline have been hypothesized to correspond to times of __________ atmospheric CO2 concentration.
reduced
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.
reduces/cooler
The snowball Earth hypothesis addresses cold periods that are thought to have involved extensive glaciation and sea-ice cover. When Earth was much colder than the present, corresponds to times when atmospheric CO2 concentration would be expected to
rise
The early anthropogenic hypothesis attempts to explain an anomalous ______ in greenhouse gas concentration over the last several thousand years as a consequence of early ________.
rise, agriculture
The largest carbon resoivior within the globocarbon cycle is:
rocks and sediments
As deglaciation proceeded, sea level _______, meaning important connections between landmasses were _______.
rose / lost
Fossil coral reefs provide direct evidence for...
sea-level changes, reflecting ice-sheet volume changes over orbital time scales
As was the case in previous interglaciations, millennial climate variability over the last 8 kyrs has been _________ in amplitude than during glaciations.
smaller
The ______ a planet's distance from the sun, the _____ the surface area of the planet, and thus, the _____ the solar constant.
smaller; smaller; larger
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?
summer
The strength of the Coriolis force acting on a moving parcel of air or water depends on all of the following except:
the heat capacity of the parcel
The lapse rate (rate of decrease in temperature with altitude) is smaller in magnitude for moist (saturated) air than for dry air because of...
the latent heat of condensation/vaporization for water
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
true
Both ablation and accumulation depend, to some extent, on mean annual temperature, but ablation is much more sensitive.
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.
true
Looking at the wind direction in the figure below, would the resulting Ekman transport be producing upwelling or downwelling along the coast of California? Arrow down in NH
upwelling
The cretaceous period is generally associated with _____ temperature and _____ carbonate deposition
warmer and more
Which process will not make a parcel of seawater more dense?
warming
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?
warming and drying
