earth processes and risks quiz V

warmer air leads to ____ water vapor, and a (greater/lesser) _____ greenhouse effect. more water vapor leads to more clouds and more albedo

more; greater

anthropogenic greenhouse gases are ones (unlike water) That humans have an influence on: CO2, methane, and fluorinated gases. 3 factors in determining level of importance

much, long, absorb energy? How much in atmosphere, how long in atmosphere, how strongly absorb energy?

important: Humans dont "create water", but warmer air--more water vapor--greater greenhouse effect. but as more water vapor--more clouds-- more ___

albedo

if albedo is how much energy is reflected back to space (solar), then 0 albedo is _____ (dark/light) in terms of light/no light reflected and 1 is ____ (dark/light).

0 dark, no light reflected; 1 very bright, all light reflected. bare glacial ice is pretty bright, .5. ocean and forests have a lower albedo .1-.3 because they are highly absorbing surfaces (less to no light is reflected)

What is the melting of glaciers and ice sheets caused by?

1) net negative surface mass balance (more melting than snowfall) - ice mass changes measured using satellite gravimetry - there is more of a loss in greenland and more a gain in east antarctica 2) Dynamic changes in ice sheet behavior (changes in ice flow that accelerate transport of ice to the oceans) ice velocities are fastest in localized ice streams. A major concern is that these ice streams will accelerate in the future.

over the last century, the average global temperature increased: ____ oC

1. Changing the temperature by 25%. This sounds small but the natural variation of the average global temperature from extreme glaciation to height of interglacial warmth is 4C total.

the current rate of acidification is decreasing sea water pH levels ))) to ___ times faster than at any other time in the past 50 million years

10-100

sea level change during the last ice age: At the peak of the last ice age, sea level was around ____ meters lower than today. The total global land mass protruding out of the water was around ____ million square km.

125m; 20 million - sea level is currently rising at about 3.5mm/yr sea rising is driven by: - melting of glaciers and ice sheets - thermal expansion of the oceans - local subsidence of the land surface

How do we know that the observed increase in CO2 levels is anthropogenic? (human-related)

13C/12C ratios. - plants when cant hold onto 12C over 13C and 14C. They tend to have more 12C than atmosphere, so the ratio of 13C/12C is LOWER than in the atmosphere. we would expect that the ratio then would correspond to lower values for burning fossil fuels. just as the anthropogenic sources, fossil fuel burning and deforestation, go up, there is a sharp drop in concentration and sharp drop in concentration in 13C/12C since the industrial revolution 1800s. so putting fossil fuels in the atmosphere and deforestation is adding more CO2 into the atmosphere and lowering the 13C/12C ratio. OTHER greenhouse gases show the same trend with natural gases, fossil fuel, deforestation, and agricultural activities like fertilizers.

if something has 2x the absorption potential of CO2, then what is its GWP?

2

modification of incoming solar radiation by atmospheric and surface processes: ____ reflected back to space from atmosphere, clouds, and earth's surface. ____ absorbed by atmosphere and clouds _____ absorbed at earth's surface

30% reflected back; 20% absorbed atmosphere and clouds; 50% absorbed earth

___ is the largest emitter of CO2. ___ is the largest as a measure per capita. emissions in the US are decreasing, but not enough to offset the increases in emissions in other countries

China; US

greenhouse gases include 1) *water vapor* 2) _____ 3) _____ 4) ____ 5) nitrous oxide N2O

Co2 carbon dioxide, CH4 methane, O3 ozone

t/f: melting of sea ice and ice shelves raises sea level

F (break up of ice shelves and melting sea ice WILL NOT raise sea level because meltwater occupies the same volume as ice. Only melting of LAND BASED ICE or transport of ICE FROM LAND to the ocean will raise sea level. the same mass of ice is less dense than water

what happens as glaciers on land melt in terms of planetary albedo

as glaciers on land melt, exposed ground and rock absorb more solar radiation than ice, further warming the area and melting the glaciers ice sheet: glacial land ice extending more than 50,000 sq km. the two ice sheets today on earth cover most of greenland and antarctica

explain planetary albedo: sea ice

as sea ice over water melts, exposed water absorbs far more solar radiation (lower albedo close to .1) than ice (close to 1), leading to greater warming and more melting of ice sheets. 90% of sunlight hitting the ocean will be absorbed and reemitted as long wavelength radiation while 90% of sunlight hitting sea ice will reflect back without being absorbed (1 albedo) this is why people are concerned about the recent reduction in polar sea ice--due to the potential for a positive feedback that escalates warming

why is the thawing of permafrost to important?

can melt huge amounts of organic matter in frozen tundra soils. the carbon in earth's atmosphere is 800-850Gt and the carbon in permafrost is 1400, > 50% of all carbon in earth's biosphere. as permafrost melts organic matter breaks down into METHANE and CO2. this can lead to a positive feedback climate.

how does the ocean influence the greenhouse effect

can take up a lot of the heat and can absorb a lot of the CO2. - BUT this is happening at a much faster rate than typical geologic systems can respond

___ ___is the process that involved carbon capture and long term storage of atmospheric carbon dioxide. what are some pros and cons

carbon sequestration pros: removes excess co2 in the air, deep injection enhances extraction of fuels like oil and methane from deposits. - easily liquefied and transported - no reports yet of leakage and not expected until 1,000 years from now. cons: - cost - high amounts of carbon dioxide will lead to ocean acidification, endangering aquatic life - if it leaks out because of structural faults, then it can be fatal. this is especially because carbon dioxide is denser than air and would remain near the land surface

difference between weather and climate: ____ refers to the average conditions/characteristics of a given region - time scales of 30+ years and examples include averages of temperature, humidity, precipitation, sunshine, etc and other phenomena that occur over a long period in a particular place. ____ is the condition of the atmosphere at a particular time and place. - it is on a time scale of minutes to months and includes changes in temperature, humidity, precipitation, cloudiness, etc.

climate is more general, average weather characteristics; weather is the specific condition of the atmosphere at one time and place

geo-engineering refers to methods to manipulate the environment to offset global warming (by reducing solar insolation). what are some examples?

cloud seeding, reflective aerosols, space mirror, ocean fertilization, forestation, air capture (issues include cost and unintended consequences)

the three types of energy transfer: ____ heat transfer from one body to another. direct contact ______ transfer of heat through a fluid caused by molecular motion (physical motion of molecules) ______ transfer of energy through electromagnetic radiation (energy transfer by photons, converted to heat when photons strike object)

conduction; convection; radiation

melting ice in greenland could ____ (increase/decrease) salinity of the North Atlantic Current and stop downwelling and altering large scale currents. this would cause dramatic _____ (cooling/heating) in europe due to the suppression of the gulf stream

decrease; cooling

thermohaline circulation is a part of the large scale ocean circulation that is driven by ____ ____ in the ocean created by surface heat and freshwater fluxes. as warm salty surface water flows north it cools and becomes ----. eventually tis water becomes deep or bottom water

density gradients; seawater is made denser by cooling and or increasing salinity

what do we know about greenhouse gas absorption peaks and the total energy balance based on greenhouse gases?

each greenhouse gas had different absorption peaks where energy is preferentially absorbed, and total absorption is the sum of the absorption from all the greenhouse gases together. earth's total energy balance is achieved through roughly equilibrium between outgoing and incoming radiation. The "greenhouse warming" greenhouse effect is NATURAL not controversial. Without the greenhouse effect, the average surface temperature would be -18Celsius or 0F. debate on climate change is associated with *enhancements* to the greenhouse effect due to human activities (global warming)

t/f: Increases in CO2 over the last century is unrelated to changes in global temperature

f (increases in CO2 is correlated with changes in global temp)

t/f: public believes that climate change is occurring and is convinced that it is caused by humans

f (the public is convinced it is occurring but remains unconvinced that we are a major cause; however, there is strong public support for implementing policies that can be used to mitigate climate change)

t/f: greenhouse gases are gases that make up a large portion of the earth's atmosphere

f (they are trace gases that make up LESS THAN .1% of the earth's atmosphere)

t/f: the GWP is a measure of how much energy the emissions of 1 ton of gas will absorb over a given period of time

f It is a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time RELATIVE to the emissions of one ton of carbon dioxide)

if the ice in greenland melted today, the sea level in boston would remain the same. Why?

gravitational attraction of the greenland and antarctic ice sheets is so large that it pulls water toward them. As the ice sheet melts this gravitational force decreases, offsetting sea level rise in neighboring regions. so gravitational force would pull the water to it and antarctic

what wavelengths do greenhouse gases absorb and remain transparent to?

greenhouse gases are transparent to the incoming short wavelength solar radiation but absorb the outgoing long wavelength terrestrial radiation. some of the infrared radiation passes through the atmosphere, and some is absorbs and reemitted in all directions by greenhouse gas molecules. The effect of this is to warm the earth;s surface and the lower atmosphere

atmospheric circulation is driven by the ___ from the ---. But why is the air circulating?

heat; sun; the air circulated because most of the atmosphere sags toward the earth's surface and 50% of the atmosphere is within 5.5 km of the surface, so the air thins at higher elevation and atmospheric pressure decreases. This is why ears pop in airplanes. air divided by temperature: troposphere, stratosphere, mesosphere. warming in the stratosphere: ozone layer absorbs UV. Cooling in the troposphere: mostly heated from below (must be at same temperature as earth's surface at ground level)

gas's effect on the atmosphere depends on 1) _____ 2) ____ 3) ____

how much gas in the atmosphere; how long in the atmosphere; how strongly does it absorb energy. The global warming potential GWP is a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time, relative to the emissions of ONE TON of CARBON dioxide.

how do we determine amounts of CO2 in the atmosphere in the past

ice core records; then the compacted snow turns to ice, the air is trapped in bubbles of air, which are extracted and analyzed for chemical compositions

_______ refers to the fact that changes in earth's orbit cause insolation changes over geologic time and control the timing of ice ages

milankovitch cycles (eccentricity 100,0000 yrs, obliquity 41,000 yrs, precession 23,000 yrs). Cycles can cause +/- 50W/m^2 in solar insolation

how is the climate controlled by earth's energy balance?

incoming solar radiation powers climate system (balance between incoming and outgoing energy from the SUN) - earth's climate controlled by the balance of incoming solar radiation and OUTGOING radiation climate affects us: - changing sea level - changing precipitation and other local climate conditions - altering forests, crop yields, and water supplies - human health, animals, and ecosystems (like ocean acidity)

if climate is controlled by earth's energy balance, what controls the outgoing radiation?

incoming solar radiation powers the climate system. about 342mW/m^2. - earth's climate is controlled by the balance of incoming solar radiation and outgoing radiation. What controls the outgoing radiation: - 1) planetary albedo: how much energy is reflected back to space 2) greenhouse effect: How much energy is trapped in the atmosphere and earth

how is ocean acidification caused and what does it lead to?

increase temp and CO2, leads to decrease in pH or increase in acidity. this causes carbonic acid to dissolve calcium carbonate, which makes up the shells of calcifying plankton. this is the same processes as in dissolution of carbonate rocks associated with sinkhole formation

the __ ____ is the measurement of carbon in earth's atmosphere. there is a 26% increase since 1960. 310-380 ppm we are adding ___ per year. the annual cycle: more plants in the northern than southern hemisphere drives it.

keeling curve; 1.7 (1ppm = 2.13 Gt carbon)

lower (delta)18O, lower 18O/16O means ___ (lower/higher) temperatures in ice. we are predicting a ____ change in global temperatures per year.

lower; 2-6 C

how does melt water lubricate the melting of glaciers and ice sheets

melt water lakes form in the spring. water widens cracks in the ice, forming vertical waterfalls called moulins. moulins = waterfalls that send the meltwater out to sea. The speed of ice moving toward the sea has more than doubled in the past 10 years in some places. ocean levels rise as ice melts into the sea.

when the ocean warms, another positive feedback mechanism is caused by ______, which cause increases in atmospheric CO2 and methane

methane hydrates

another hidden source of carbon is in ___ ____ which form in permafrost or shallow sea floor areas.

methane hydrates (methane ice) destabilization of methane hydrates due to ocean warming can lead to an additional positive feedback mechanism increasing atmospheric CO2 and methane

compare the different greenhouse gases: Methane, Nitrous oxide, fluorinated gases, CO2 which has the largest % that comes from human activities? how long is the gas in the atmosphere? how strongly does the gas absorb energy?

methane: greater than 60% comes from humans - industry, agriculture, waste management creates it - short residence time in atmosphere compared to co2 - nitrous oxide: - 40% comes from humans - same as methane (producers) - larger global warming potential Fluorinated gases: - no natural sources, replacement for CPCs. - GREATEST global warming potential, longer lasting, but relatively small fraction of global greenhouse gas budget CO2 - 82% of all us emissions in US CO2. So primary greenhouse gas emitted from all human activities - global warming potential is low but residence time long in atmosphere - human related emissions are responsible for the increase of them in the atmosphere since the industrial revolution (even though can be released by natural means too)

explain concerns about the melting of glaciers and ice sheets caused by dynamic changes in ice sheet behavior

one way that ice streams can speed up is the disintegration of nearby ice shelves, which wold normally hold the inland back. ice shelves hold back land ice, which if falls, contribute to sea level rise.

melting all greenland ice sheet would raise sea level by 7.4 m and melting the antarctic ice sheet would raise sea level by 58.3 m. Melting all other glaciers and ice caps would raise sea level .4m. currently, what accounts for the majority of sea level rising?

other glaciers and ice caps

_____ is frozen soil or rock remaining below 0C for at least 2 years. the ____ is the top layer of soil that thaws during the summer and freezes during the winter.

permafrost; active layer (the oldest permafrost is 2mil years old)

if there are greater extremes of wet and dry, climate change will exacerbate current trends. areas close to the poles and equator will become ____ and areas in the mid latitudes will become ____

poles and equator wetter; mid latitudes warmer and drier (earlier snow pack melt will cause spring flooding and summer droughts. the northern part of the globe will have an increase in agricultural yields and the southern portion will have a decrease)

some risks of climate change include

precipitation changes: warmer air can hold more water: greater risk of storms, hurricanes, flooding and landslides. And risk of drought, freshwater loss, and decreased crop yields, and desertification

implications of climate change

sea level change (melting of sea ice, ice sheets, and glaciers) severe weather patterns; flooding and drought; spread of invasive species; thawing of arctic permafrost; solution of CO2 and ocean acidification

explain the temporal variations in solar insolation with regard to seasons and the 11 year cycle due to sunspots

seasons: - isolation varies more dramatically with the seasons as the poles compared to the equator, and these variations in insolation explain earth's seasons. - the total solar irradiance is cyclic on an 11 year cycle and correlates with the number of sunspots. - they are tegions of the sun's surface that are temporally cool and dark compared to surrounding regions. they are created when there is enhanced magnetic activity, and the sun emits more UV and visible radiation. - irradiance is a balance between darkening from sunspots and brightening from accompanying hot regions called FACULAE (Bright torch in latin) SO: the faculae offset the sunspots, leading to INCREASED amount of solar irradiance.

why are greenhouse gases important?

short wavelength radiation (UV visible light) easily passes through the atmosphere and heats up the earth's surface. long wavelength radiation (infrared radiation) re-emitted by earth's surface (like when absorbed in the ocean and reemitted as long wavelength) is absorbed by gases in atmosphere and re-emitted back to the surface. the greenhouse gases effectively "trap" the heat this way

____ is a measure of solar radiation energy received on a given surface area in a given time this is largest when the surface directly faces the sun (so the EQUATOR rather than POLES)

solar insolation (as the angle increases between the direction at a right angle to the surface and the direction of the rays of sunlight, the insolation is reduced in proportion to the cosine of the angle) solar insolation caries on the day and night scale and an annual scale. - it changes on a 24 hour cycles as earth rotates on its axis and the insolation varies with the seasons due to the tilt of the Earth's axis relative to its plane of rotation around the sun

_____ is a measure of solar raiation energy received on a given surface area in a given time. ____ is the output of light energy from the entire disk of the sun, measured at earth.

solar insulation measure of solar radiation energy received on a given surface area; solar irradiance is the output of light energy from the entire disk of the sun measured at earth

how to we reconstruct temperature in the past?

stable oxygen isotopes: 18O and 16O preserved in sediments, glacial ice or the shells of marine organisms. the light 16 oxygen and heavy 18 oxygen isotope are bonding with hydrogens in warm water. different isotopes tell us different temperatures through time. the oceans have a certain amout of 16 and 18 in the water. Preferentially, 16 evaporates into the water, rains back into the ocean or trapped in ice. During ice age, more ice on land and preferentially trap 16 in land. 18/16 ratio in shells provides global record of ice volume. ice sheets are enriched with lighter 16. lower 18/16 ratio during cold climate. More water stored on continents as ice and snow during cold climate.

Blackbody radiation: the sun's wavelength is primarily ___ wavelength vs the earth's ____ wavelength

sun is hot: short waves; earth is cooler, radiation is all in long wavelength spectrum

t/f: In terms of CO2 emissions, the 20th century is clearly anomalous when compared with the last millennium

t

t/f: in terms of the energy balance at the earth's surface, the heat flowing out of the earth is negligible in comparison to that from solar energy

t

t/f: while the earth is in a warm period with respect to the last 100,000 years, the earth is very cool on the time scale of the last 60 myrs

t

T/f: Because the sun is hotter than the earth, it produces more radiant energy at shorter wavelengths

t (300K emittance vs sun's 5,777K emittance. Earth has longer wavelengths than the sun)

t/f: loss of glacial ice also decreases albedo, causing further warming

t (as melt more ice, lower albedo because darker oceans, positive feedback more heat in system, causes global warming)

t/f: Faculae (the hot regions) offset the effects of sunspots, and create more solar radiance

t (but it is a very tiny variation: .1% every 11 years)

t/f: greenhouse warming is normal, not controversial

t (greenhouse effect was studied by Joseph Fourier in 1827, who published a paper describing how temperature is controlled by the balance of incoming and outgoing radiation. Debate on climate change is associated with the enhancements to the greenhouse effect due to human activities) the human enhanced greenhouse effect is explained by more greenhouse gases, more re-emitted heat, and less heat escapes into space

t/f: sea level rise will significantly increase the potential flood risk in coastal areas over the next century

t (the hardest hit places will be louisiana, florida, and north carolina. 5 billion of the world's 6.8 billion live in low lying areas)

incoming solar radiation peaks in the ___ ___. Solar radiation at sea levels is reduced compared to that at the top of the atmosphere due to ___ and _____ in the atmosphere. - absorption is focused in*bands* corresponding to specific *atoms/molecules*

the solar radiation coming to the earth peaks in the visible spectrum; solar radiation at sea level reduced because of reflection and absorption of the radiation in the atmosphere.

Explain the carbon Bathtub and its components:

the sources of carbon are the faucet, including fossil fuel combustion and deforestation. the drain, or the sinks of carbon is explained by land uptake and ocean uptake. Fossil fuel burning + deforestation > ocean uptake and land uptake the current sources of carbon exceed the net sinks of carbon. This means that the bathtub is filling up, or there is an increased concentration of co2 in the earth's atmosphere.

_____ ___ drives large scale ocean current across the ocean basins.

thermohaline circulation

___ is the most abundant greenhouse gas on earth a) Methane b) Water vapor c) Nitrous oxide d) Carbon dioxide e) Ozone

water vapor (water vapor not only plays a role as a greenhouse gas, but it also controls the Earth's albedo; - amount of water vapor depends on the temperature through evaporation from the oceans and transpiration from plants, and water vapor tends to reinforce rather than drive climate change. warmer air, more vapor, greater greenhouse effect. more water vapor--more clouds, more albedo.