EPS 7 Midterm 2
from today's fracking, how many GtC have gone to the atmosphere? to the ocean?
+250 GtC--> atm +150 GtC--> ocean
what is DDT
- a chemical that people used to douse themselves with because they thought it would make them immune to polio but it was actually toxic -ddt bioaccumulated and destroyed the eggshells of raptors, eagles etc (bad for higher up in the food chain)
what are some evidences of warming?
- tropical glaciers - borehole temperatures - surface-air thermometers - satellites
what is Earth's total feedback parameter?
-1.1W/m^2/K
what is the total forcing of our earth and how much warming is caused by it
-2.5 W/m^2 - final perturbation= forcing/ -feedback parameter - 2.3K= 2.5/1.1
how do satellites provide evidence for global warming?
-Advanced Microwave Sounding Unit (AMSU)=most imp tool for measuring temp from space by picking up microwave signals emitted by earth's atm -these satellites have polar orbits (take over the poles) and are sun-synchronous (the ascend and descend over the equator at the same time as regional day and night on each orbit) -AMSU channels are all clustered on the side of an oxygen resonance which is a peak in k (the constant) bc a high k for O2--> a higher Tau=1 surface high in atm -how much power the AMSU gets in wavelength corresponds to the temperature at a different heigh in the atm
what are the sources of halocarbons
-a carbon atom with some halogen atoms stuck to it (Cl, F) -have a radiative forcing thats 100s-1000s times greater than co2 but halocarbons aren't from combustion but rather from air conditioning, fridges, production of foam (hairspray) -they generate the ozone hole so they are regulated
what is an acid? what is acidic water?
-a molecule that can give up an H+ ion -water with a lot of H+ ions
what is earth's climate sensitivity and how did we get this number
-about 3K -we use the forcing from a doubling of CO2 (3.7) and combine it with earth's feedback parameter (-1.1)
what are grid cells
-boxes that weather and climate models discretize the world into -if you warm up a grid box, circulation will develop because the cells will hand off mass to each other through their faces
what are the high clouds?
-cirrus -cirrostratus -cirrocumulus
what are the three types of fossil fuels?
-coal (C or CH) -Oil (CH2) -gas (CH4)
what is the IPCC
-combo of WPO and UNEP -the intergovernmental panel on climate change -it summarizes the state of science, doesn't generate new info -has 5 assessment reports
what are the sources of nitrous oxide (N2O)
-farmland, poop, AGRICULTURE, fossil fuels -we are using nitrogen compounds as a fertilizer (sprayed on fields and returns back to the atm as N20)
what is coal
-fossil fuel that came from carboniferous era 300 Mya -fossilized peat (wet soil at the bottom of a swamp) -as layers of sediment weigh down the peat, it dries out, loses almost all the oxygen and hydrogen--> coal
what are conservation laws
-fundamental principles of physics that tell us that matter is neither created nor destroyed -mass, momentum, and energy are conserved
what happens if you point the infared thermometer upwards into the sky
-if the atmosphere doesn't absorb and emit the longwave, it will report back 3K (temperature of space) -if the temperature does absorb and emit the longwave, it will report back 200-300K (temp of atm)
why is increasing co2 levels an example of positive forcing?
-increasing co2 levels--> decreases outgoing longwave radiation-->positive net flow of energy into the earth -the higher the density of co2, the higher the altitude of the tau=1 surface emitting to space and the higher up in the atm, the colder it is (acc to stefan boltzmann, a colder tau=1 surface radiates away less power)
what is oil
-middle east oil came from jurassic period 150 Mya -oil is fossilized plankton (small organisms that live in the ocean) -compressed to high temperatures and pressures -gas=overcooked oil -at high temps and pressures, oil-->natural gas -much of today's oil is formed in the Tethys sea
describe ocean acidification and its effects
-more co2 in the atm-->more carbonic acid-->more acidic ocean -big deal for calcium carbonate (CaCO3) making it difficult for animals that rely on this
why is climate sensitivity defined in terms of a doubling
-more convenient -each doubling gives roughly the same amount of warming
what three processes remove co2 from the atmosphere and with what timescale?
-ocean acidification/adding co2 to water (1000 yrs) -dissolution of CaCO3 (10,000 yrs) -silicate weathering (100,000 yrs)
what happens in respiration?
-opposite of photosynthesis -after respiration (ie after digesting food), the carbon is on the oxygen which generates water and co2, so when you exhale, you exhaust co2 and the h2o leaves in a bunch of other ways
what happens in photosynthesis?
-plant (H-C-O-H) takes in H20, sunlight photon, and CO2 and lets out O2 -after photosynthesis (ie after a plant grows) the carbon is on the water which generates plant matter (CH2O) and oxygen -when a plant grows, it converts CO2-->O2
how does the atmosphere interact with radiation
-scatters some shortwave -absorbs and emits longwave
what is the greenhouse effect
-shortwave photons are let in but are trapped by slowing longwave emission and convective cooling -enhancement of solar radiation whereby the surface receives twice as much radiation from the atm as it does from the sun
after 10,000 yrs, what happens to the remaining 20% of burned carbon still in the atm
-silicate weathering: silicate rocks weather when they are exposed to CO2 to make calcium carbonate -after this, all the remaining carbon put into the atm by humans is removed by silicate weathering
what is a methane clathrate
-substance consisting of crystalline lattice of cages made of water and trapping CH4 inside -looks like snow or ice but it burns -resides in ocean sediments
what is climate sensitivity
-the change in mean global temperatures for a doubling of atm CO2 concentrations from preindustrial levels (pre 1800) ie) from 280-->560 -also known as Equilibrium Climate Sensitivity (ECS) to emphasize that we wait until the Earth equilibrates (abt 100 years) to the new CO2 level before differencing the mean temperatures
what is feedback
-the extra flow in excess of the steady state flow -response to flows in perturbation
who was joseph fourier
-the person who first postulated the greenhouse effect -calculated the earth's temperature in the 1800s like we did and also got too cold of a temperature -in 1824, he identified the problem: our atm is interposed; shortwave photons are let in but are trapped by slowing longwave emission and convective cooling -introduced the world to climate science by asserting that without an atm, earth would be naked in space and cold
Who is Svante Arrhenius
-the person who first predicted global warming in 1896, making the first prediction of Earth's climate sensitivity -predicted 5K for climate sensitivity and the current estimate is 3K
who was Jules Charney
-the person who gave the first modern estimate of climate sensitivity through the 1979 Charney Report -said the equilibrium surface global warming due to doubled CO2 will be between 1.5-4.5w/ most possible value at 3 (hasn't changed)
who was John Tyndall
-the person who identified the gases which were responsible for the greenhouse effect -discovered that N2 and O2 (the main constituents of air) and Argon are transparent to longwave radiation but other trace gases (H2O, CO2 and CH4) readily absorb and emit longwave radiation (before, gases were thought to be transparent to radiation) -built an instrument that measured longwave absorption of gases -presented his results in 1859
who was charles david keeling?
-the person who woke scientists up to global warming -made measurements in Big Sir, and Mauna Loa to find the concentration of co2 -second year of measurements at Mauna Loa showed that there is an annual cycle -showed unambiguous rising of CO2
what are the sources of O3
-the three o's don't really want to stick together so they will give off one o (we like the ozone up in the stratosphere bc it blocks off UV but here, it has chemical effects and readily absorbs radiation) -VOCs (volatile organic compounds) and Nox when these are exposed to sunlight--> ozone -urban smog
why does the earth "breath" with the annual cycle? what makes measurements cyclical and changing?
-there is much more land in the northern hemisphere than in the southern hemisphere which leads people to make goofy maps -if the SH and NH has the same amount of land, they would cancel. but they don't... -thus, in the NH summer, plants grow--> photosynthesis>respiration--> co2 removed and vice versa in the NH winter
how can we use surface air thermometers to provide evidence for global warming?
-use a stevenson screen (a thermometer enclosure that shades and ventilates and is used for surface air temp measurements designed by thomas stevenson in 1864); analogs that measure min and max temps -linear regression from findings show that there is a 1.5K increase per century and after 1.24 centuries, 1.4x1.24=2K increase
how can we use borehole temps to provide evidence for global warming?
-use borehole paleothermometry (measurement of old surface temperatures by lowering the thermometer down a borehole) -with global warming, the more you descend, the more you are sampling mean annual surface temperatures from long ago -measurements throughout the world see a mean warming of about 1K from preindustrial times (this finding has been replicated many times)
what went wrong when we calculated the temperature of the earth?
-we hypothesized 255K but that is actually the temperature at which Earth radiates to space, not the temp of the surface (255K is the temp of the Tau=1 layer of greenhouse gases) -we needed to find the temperature of the surface using the 6.5K/km lapse rate -Thus: 255+ 6.5x5(height of tau=1) =288K
who is James Hansen
-woke the public up to global warming through his 1988 congressional testimony, documenting the rise in global mean temperature -used NASA GISS model to forecast future warming
how can we use tropical glaciers to provide evidence for global warming?
-you can date different depths of ice by counting annual layers, giving a min age for these glaciers -these glaciers are disappearing for the first time in at least 1000s of years
when did civilization begin?
0.01 Mya
Peat accounts for 200 GtC out of the 1500 GtC down to _______
1 m
what are the sources of methane in the atm
1) livestock (cows) burps and other ruminants generate 1/3 2) landfills and rice patties (1/3) 3) fugitive natural gas (a molecule of CH4 causes 4x the radiative forcing as a molecule of co2 but ch4 oxidizes to co2 in 10 ears and co2 lasts in the atm much longer)
what is some evidence of atm scattering of shortwave radiation?
1) the way we see colors: via N2 molecules, we see colors because of Rayleigh Scattering by molecules which redirects photons into a new direction (shortwaves ie blue are more scattered than long waves ie red or infared); the more of a path a photon has to travel the more it is scattered 2) clouds; they scatter sunlight by Mie Scattering which scatters via big cloud drops (bigger than N2) so al wavelengths are scattered, thus clouds are white
how do you calculate land warming?
1.5 x global warming
how many main cloud types are there?
10
by how much does atmospheric co2 rise each year?
10GtC of emissions--> 5 to atm, 5 to oceans--> 5GtC in atm/2=2.5 ppm
what are the current global emissions of CO2/year and when do they double?
10GtC/year (and rising exponentially) and they double every 23 years
when was the big bang
14 Gya
over all depths, permafrost contains ________
1500 GtC
how much atm co2 could we be emitting by 2100
1500 ppm, more than a quadrupling -but the likely BAU CO2 concentration in 2100 is around 1000ppm
at the current rate of combustion, CO2 is rising ______ ppm/year
2
on average, the earth gets ____ times the radiative power from its atmosphere than it does from the sun
2
1ppm=____ GtC
2 (2.13)
what is the temperature in the atmosphere?
200-300K
what does adding 250 GtC to the atmosphere increase concentrations by?
250/2.13=120ppm 120ppm+ preindustrial concentrations of 280ppm=400ppm (half a doubling)
what was the preindustrial CO2 concentration
280 ppm (for every 1,000,000 air molecules, 280 were CO2)
what does doubling co2 generate a radiative forcing of?
3.7 W/m^2
how long are the steps a climate model generally jumps from
30 min
of the 1500 GtC down to 1 m, permafrost accounts for:
350 GtC
what is the temperature in space?
3K
americans emit ______ times as much co2 per person than the global average
4
f we hold the concentrations of greenhouse gases constant at the levels anticipated in 2100 for the RCP4.5 scenario, roughly how much globally averaged warming would we get if we waited long enough?
4
when was earth formed
4.5 Gya
how much of the dissolved/burned carbon can be hidden as bicarbonate in the ocean?
60% on a timescale of 1000 yrs (timescale is so long because the ocean is big and that's how long it takes to fully circulate)
the current population is ______ and will rise to ______ by 2100
7 billion, 11 billion
If we hold the concentrations of greenhouse gases constant at the levels anticipated in 2100 for the RCP8.5 scenario, roughly how much globally averaged warming would we get if we waited long enough?
8
how much carbon is hidden as bicarbonate in the ocean after calcium carbonate dissolution
80% on a 10,000 yr timescale
what are the negative forcings in the atmosphere?
Aerosols (-1 W/m^2): any suspension of small particles into earth -tends to decrease the net inflow into the earth -volcanic ash, pollen, sea salt, soot -sulfate aerosols are microscopic drops of sulfuric acid which comes from car/factory emissions -increases albedo of our planet and reflects sunlight back into space
what are the positive forcings
CO2, CH4, N2O, Ozone (O3), Halocarbons
what is the chemical formula for the dissolution of calcium carbonate?
CaCO3--> Ca++ + CO3-- Ca++ + CO3-- + H+ --> Ca++ +HCO3-
What chemical reaction ultimately removes the excess carbon from the atmosphere and ocean?
CaSiO3 + CO2---> Ca++ + CO3-- + SiO2---> CaCo3+ Sio2
what are some environmental laws that got signed in the 60s and 70s
National Environmental Policy Act Clean Air Act Environmental Protection Agency Clean water act Endangered species act also created the UN Environment Programme
What book focused on the toxicity of DDT and is credited with kicking off the U.S. environmental movement in 1962?
Rachel Carson's Silent Spring
what does stratus look like
a layer of fog
what is the active layer
a layer of soil in permafrost that thaws out temporarily at some part of the year
what does nimbostratus look like
a rain layer, foggy, some clouds
what does cirrostratus look like?
a ring around the sun
what does cumulus look like
a scoop of ice cream
what is an infared thermometer
a tool that measures the power per area in infared radiation emitted by an object that you point the thermometer at. It then measures the temperature needed to emit that power per area by using 6x(T/100)^4
what are the middle clouds
altostratus altocumulus
forcing
an externally applied change in the flows -positive forcing increases the stock -a negative forcing decreases the stock
what was the World Meteorological Organization (WMO)
an organization established to exchange weather data between countries, later becomes part of the UN
what is the water vapor feedback
as earth warms, the air holds more water vapor which causes less outgoing longwave radiation (bc its a greenhouse gas) causing a warming tendency--> positive feedback)
what is the lapse rate feedback
as earth warms, the lapse rate changes, causing the tau=1 surface to be warmer than it was before, causing more outgoing longwave radiation which, in turn, creates a cooling tendency (negative feedback)
where does emission of longwave radiation to space occur
at about 5km (tau=1 surface)
at what point does a gas emit to space
at the Tau=1 surface
in preindustrial times, how many GtC were in the atmosphere, land plants, soil, and oceans?
atm= 600 GtC Land plants= 500 GtC soils= 1500 GtC oceans= 40,000 GtC
what have soils and plant not been a net source or sink of ocean/atm carbon?
because carbon flux from land use has been balanced by new growth (so land plants portion is not relevant)
most of the carbon in the ocean is in what form?
bicarbonate (HCO3-) it's a charged ion so it cannot leave
what is HCO3-
bicarbonate ion
G=
billion
what is the planck feedback?
by the stefan-boltzmann law, a warmer earth has more outgoing longwave radiation which creates a cooling tendency (negative feedback)
after 1000 yrs, what happens to the remaining 40% of the burned carbon that remained in the atm
calcium carbonate dissolves from the ocean floor and on land, raising the pH and allowing more co2 to dissolve into the ocean
describe the mvmt of carbon over the last 100s of millions of years
carbon moves out of the mantle and into volcanos--> atm-->organisms, oceans and sediments--> back to the mantle -a tiny fraction of that carbon has been buried in the earth's crust as fossil fuel
what is CO3--
carbonate ion
what is H2CO3
carbonic acid
what is the equation for optical depth?
change in tau=(k;constant)(rho;density)(change in z;distance)
what does stratocumulus look like
close, large and dense clumps of cloud
how much of the fossil fuels has the world used so far?
coal= 200 GtC burned oil= 150 GtC burned (we have gone through roughly 1/2 of oil) gas= 50 GtC burned
in preindustrial times, how many GtC were in coal, gas and oil?
coal= 5,000 GtC gas= 250 GtC oil= 350 GtC
true or false, for long wave in the atmosphere, there is some scattering but very little absorption and emission
false, for shortwave
T/F: global warming is caused by an increase of incoming power
false, it is caused by a decrease in outgoing power (which leads to a positive forcing or increasing the planet's stock of power)
true or false: whether the perturbation in a water tank is positive or negative, the slit always provides a positive feedback
false, negative feedback because negative feedbacks always dampen perturbations, no matter what sign (make it less negative or less positive)
how do conservation laws tell a climate model what to do
for energy/mass/momentum conservation: rate of change of a grid cell's (energy) =flow of energy in-flow of energy out
final perturbation= _______/________
forcing/(-feedback parameter)
what units do we use to measure the amt of co2
gigatons of carbon (GtC) 1 GtC=3.7Gt of Co2
what are some forcing agents in climate?
greenhouse gases
cirrus
hair
cumulus
heap
how do you quantify this opacity?
in terms of optical depth (Tau) where - T<<1 transparent - T is about 1 in between - T>>1 opaque
positive feedback
increases the size of perturbation
what are flows
inputs and outputs for a container of stuff
what makes the earth so different than mercury and mars
it has an atmosphere
if a gas is optically thick with respect to scattering but optically thin with respect to absorption, what can we conclude
it scatters before it has a chance to absorb
what is one way to measure the melting of permafrost?
keep track of the lakes above permafrost (satellite images reveal changes in permafrost lakes-disappearing)
strato
layer
when were coal, oil and gas formed
made from organisms formed roughly 100-300 Mya
what is a supercomputer
made up of thousands to millions of regular computers wired together for parallel computing
alto
middle
M=
million
scooping out a cup of water from the tank is an example of _________
negative perturbation
what does it mean if the slit lets out water slower than it is coming in
negative perturbation because it is casing the water level to increase
what to negative forcings in climate do
net cooling impact from forcing
what do forcings in climate do
net positive inflow of power
with a negative feedback, a forcing tends to lead to a:
new steady state
what are the clouds of vertical development
nimbostratus cumulonimbus
is the cloud feedback certain?
no
is the huge amt of carbon in the ocean a threat?
no, it is dissolved carbon dioxide
Is the following an example of a gas radiating thermal energy: lightning
no, lightning bolt is too narrow to have a tau=1 surface,
Is the following an example of a gas radiating thermal energy: a candle
no, tau=1 surface is not within this tiny flame
Is the following an example of a gas radiating thermal energy: fluorescent lightbulb
no, this is just the ionization of mercury exciting electrons into a chemical coating
how much radiative forcing are aerosol cans responsible for
none
how much carbon is trapped in methane clathrates?
not definitively known but between 1000-10,000 GtC -releases co2 when it melts
what is a climate model
not something you click or watch, but something you read and write; coding
what is ppm
parts per million 1/1,000,000
negative feedbacks make the rich _________ and the poor ________
poorer; richer
the more money you have in the bank the greater the interest (and vice versa). This is an example of:
positive feedback (because it grows perturbation)
what does it mean if the slit in a water tank lets out water faster than it is coming in
positive perturbation because it is making the water level decrease
nimbo
rain
negative feedback
reduces the size of perturbation makes steady states possible
what are RCP's
representative concentration pathways (IPCC postulates them) and are labelled by their forcing
the higher the density, the _______ the distance (change in z) needed to get to the Tau=1 surface
shorter -today, earth has greater density
what does cirrocumulus look like
small clumped strands of hair
what is permafrost
soil that is frozen all year -can exist in places where the mean annual temperature is below freezing -keeps carbon fresh all year by trapping it -with global warming it is thawing and releasing co2 AND CH4 into the atm
at each unit increment in Tau, the gas behaves like the surface of a _____ body
solid
what does altocumulus look like
sort of far away clumps of cloud that are not very dense
what does altostratus look like
sort of like a fog but higher up with a singular small clump of white where the sun should be
climate models discretize both ______ and ______
space and time
what are the lower clouds
stratus stratocumulus cumulus
in the _______ photosynthesis>respiration whereas in the _________ respiration>photosynthesis
summer; winter
how were weather forecasts made in 1857?
telegraph
what is stock
the amount of stuff in the container
feedback parameter
the change in net inflow per change in stock(ie perturbation) -quantify feedbacks
what does pH measure?
the concentration of H+ ions in the water
what is perturbation
the extra water in the tank (in excess of the steady-state stock) current stock-stock in the original steady state
what is evidence for atmospheric absorption and emission?
the fact that we cannot use our eyes to see certain wavelengths because our eyes are essentially made out of water and water is opaque in infared radiation
if a gas is optically thin with respect to scattering but optically thick with respect to absorption, what can we conclude
the gas absorbs before it has a chance to scatter
what is the Tyndall effect
the preferential scattering of blue light
what is global warming?
the response of earth's steady-state heat budget to a positive forcing from greenhouse gases in the atm
what is carbonate chemistry
the set of reactions which move carbon between carbon dioxide, carbonic acid, bicarbonate and carbonate
what is a timescale
the time it takes something to get mostly done
k=
thousand
true or false, a gas can be optically thick with respect to one wavelength and optically thin with respect to another
true
true or false, for longwave radiation in the atm, there is very little scattering but a lot of absorption and emission
true
true or false, the Stefan Bolztmann law applies only to solid surfaces
true
true or false, the deeper and deeper into the absorbing gas (the higher the tau) the more opaque the gas
true
true or false, the more co2 there is, the more efficiently the stratosphere sheds the heat gained by UV so the cooler it is
true
true or false, each time you increase CO2 by 280 ppm, you get a slightly smaller amt of warming
true (to a certain pt)
true or false, the drier the peat, the more readily it burns. why or why not
true; bc the higher the temperature (global warming) the greater pv* and the drier the soil and the more readily it burns
what does cumulonimbus look like?
volcano
the troposphere is _________ while the stratosphere is ________
warming; cooling
How have we accounted for absorption and emission
we have not yet accounted for this
how have we already accounted for scattering?
we use an albedo of 0.3
storms move _______ to ______ in the US
west to east
what does optically thick mean?
what we call a gas if it is opaque to radiation and the radiation does not go all the way through
what does optically thin mean?
what we call a gas if it is transparent to radiation and the radiation does go all the way through
what is serial computing
when a single computational problem is solved by a single computer
what is parallel computing
when a single computational problem is solved by many computers parallel to each other by breaking down the computation into chunks and communicating with one another (each one is responsible for something else)
what is the cloud feedback
when it is warmer, there are fewer clouds and a lower albedo causing more sunlight absorption and having a warming tendency (positive feedback)
Ice feedback
when it is warmer, there is less ice and snow, lowering albedo, absorbing more sunlight and creating a warming tendency--> positive feedback (like cloud feedback but with ice and snow)
what is steady state
when the total flow in=total flow out; stock is constant in time
what does weathering mean
when you wear a rock away by exposure to weather
what does cirrus look like
wisps of hair
who is luke howard?
wrote a paper in 1803 that classified clouds with latin
ya=
years ago
Is the following an example of a gas radiating thermal energy: our atmosphere
yes, it emits longwave radiation downward
Is the following an example of a gas radiating thermal energy: the sun
yes, tau=1 layer is the photosphere whose temp is 6000K and this is where our sunlight comes from