Geology 150 Usc – Flashcards
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How old is the Earth?
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4.5 billion years
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What are components of the climate system?
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Atmosphere, Hydrosphere, Cryosphere, Biosphere
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What is the atmosphere made of? Where did it come from?
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Nitrogen (N2)- volcanic Oxygen (o2) - photosynthesis Argon (Ar)- volcanic
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Why does the composition atmosphere not tell the whole story?
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Minor gases like carbon dioxide (CO2) and water vapor(H2O) major impact on global warming.
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Where did atmospheric dioxygen come from? Was it always there?
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Atmospheric dioxygen wasn't present on earth until 1.7 billion years ago and came here through photosynthesis. Atmosphere primarily formed by degassing of the earth's mental
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What are permanent gasses?
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Some gases are called permanent because their residence time is fairly long and they have a high exchange rate as well.
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What are variable gasses?
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Some gases are called variable because their residence time is fairly short and their atmospheric reservoir is fairly low (low exchange rate).
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What is residence time?
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Residence time can best be thought of as the time it takes to fill a reservoir, once emptied.
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What are the two kinds of energy present in air parcels or water?
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Thermal energy and mechanical energy
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What does mechanical energy consist of?
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Kinetic energy and potential energy
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What characterizes energy (in a closed system)?
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Thermal energy (heat) = sensible + latent energy, it can change form but the total energy is conserved
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What are the two ways to alter the thermal energy of a system?
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work and heat
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What is heat? Which forms that it takes?
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Heat is the process of transferring thermal energy from one body to another due to thermal contact.
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What is sensible energy?
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The portion of the internal energy of a system associated with kinetic energies of the molecules.
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What is latent energy?
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The internal energy associated with the phase of a system.
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What is specific heat?
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The amount of energy necessary to change 1 kg of matter by 1 degree Celsius.
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How can heat be transferred from one body to another?
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Conduction, convection (or advection), radiation
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What is conduction and what does it require?
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Heat energy is transmitted through collisions between neighboring molecules. Needs a medium but no circulation
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What is Convection (or advection) and what does it require?
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Collective movement of groups of molecules within fluids. Needs both a medium and circulation
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What is radiation what does is require?
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Transmission of energy in the form of waves or particles through space. Needs no medium or circulation
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What does wavelength tell us about an electromagnetic wave?
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The shorter the wave length the higher the energy (or temperature)
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What is blackbody radiation?
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A blackbody refers to an opaque object that emits thermal radiation. A perfect blackbody is one that absorbs all incoming light and does not reflect any light.
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What laws characterize black body radiation?
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Stefan Boltzmann's law, Wien's law
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What does Stefan Boltzmann's law tell us?
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total amount of energy radiation emitted (flux) is a function of a constant * temperature.
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What does Wien's law tell us?
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The wavelength is of an object is equal to a constant/temperature.
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In the visible domain, what is the popular term for 'wavelength'?
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Color
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What range of wavelengths does the Sun emit in?
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sun: emits short wavelength in the visible range (shorter than 4um). Ultra violet radiation is emitted by the sun
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What range of wavelengths does the earth emit in?
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Earth: emits long wavelengths in the infrared range (longer than 4mm). Thermal infrared is emitted by the earth.
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Which kinds of radiation is present in a beam of sunlight?
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Near infrared radiation, shortwave radiation, electromagnetic radiation
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Which kind of radiation is not present in a beam of sunlight
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radiowave radiation
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What is the defining characteristic of a greenhouse gas?
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It prevents (earth) long wave radiation from leaving but lets the short wave length radiation in (sun).
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When are latitudinal insolation contrast the greatest?
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When solstices are present.
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How does the atmosphere behave with respect to short wave and long-wave radiation?
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It let's in most of the sun but it blocks most the earthlight from leaving. So, it is mostly transparent to incoming solar radiation but it prevents long wave radiation from leaving. This is due to the greenhouse gases.
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What are today's major greenhouse gases?
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Carbon Dioxide (CO2), Methane, Nitrous oxide (N20), Water vapor
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Energy flux is measured in?
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watts
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What would be the Earth's equilibrium temperature without an atmosphere?
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-1 Fahrenheit/255 kelvin/ -18 celcius
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What would be the Earth's equilibrium temperature with an atmosphere?
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60 Fahrenheit/288 kelvin/ 15 celsius
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By how much is the greenhouse effect warming the Earth?
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33 kalvin
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What factors determine the planet's average temperature?
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Albedo, solar constant, emissivity (epsilon)
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What is albedo?
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This is the reflection of some incoming radiation.
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What is emissivity (epsilon)?
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This is the amount of radiation that is allowed to be escape the surface (factor between 0-1). So, a perfect blackbody has an emissivity = 1. Earth is 0.6.
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What is the solar constant?
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This is the amount of radiation that comes to the earth to start with.
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Why are there seasons?
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Because of the tilt of the earth's axis, angle of the sun's impact (incidence) due to earth revolution.
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What is albedo?
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The amount of radiation reflected by the earth as a whole, this is caused by the reflection of the atmosphere, clouds and ground.
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When does a point in the Northern Hemisphere receive the most insolation from the Sun? and when least
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Most: Summer solstice - june 21 (summer), least: Winter solstice - dec 22 (winter).
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When does a point in the Southern Hemisphere receive the most insolation from the Sun? and when least
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Most: Summer solstice - dec 22 (summer), least: Winter solstice - June 21 (winter).
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What time of the year does every location on Earth get 12 hours of sunlight?
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Equinox - march 21 and September 21
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What is the residence time of water in the atmosphere? (Compare to CO2)?
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10days - water, 400 years - co2
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What is the water vapor feedback?
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Water vapor feedback is the process by which high temperature increase evaporation of water. As a result, there is more water vapor in the atmosphere. Due to higher water vapor concentrations of water vapor, more heat gets trapped and this will lead to more evaporation. Due to the increase in water vapor the climate increases in heat and this is a positive feedback.
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Can a positive water vapor feedback only warm the planet?
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No it can also cool the plant. This happens when low temperatures decrease evaporation of water. As a result, there is less water vapor in the atmosphere. Due to the decrease in water vapor, less heat gets trapped and this will lead to less evaporation.
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Which planet had a runaway greenhouse effect due to the water vapor feedback?
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The baseline temperature on Venus was so high that early oceans evaporated.
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What roles does water play in climate?
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It makes clouds (evaporation), it creates a greenhouse gas, it serves as an energy vector: warm air is more sutured (more cloudy) than cold air, it makes ice
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Are clouds warming or cooling climate? What does this depend on?
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This depends on whether we are referring to low or high clouds. Low clouds cool the surface and high clouds heat the surface. This is due to the fact that low clouds have higher albedo than high clouds resulting in a greater deflection of radiation.
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What are major forces acting on an air parcel?
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Pressure gradient force, buoyancy, friction, coriolis force
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What is the pressure gradient force?
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This force results from the uneven distribution of radiation. As a result, this causes difference in pressure across a surface. These differences in pressure result in differences of force.
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What is Buoyancy?
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This is the force that results from the gravity acting on density differences.
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What is friction?
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This is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.
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What is the Coriolis force?
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Apparent force due to rotation. It acts on the right in the northern hemisphere and to the left in the southern hemisphere. It is an artifact of our frame of reference.
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What is the ultimate cause of atmospheric motion?
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Pressure gradient force
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Which way does it change the motion of an air parcel?
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Because it acts at a right angle to motion it cannot change the kinetic energy of motion (speed) it can only change the direction of the motion.
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What is the name of the atmospheric circulation cell between the equator and 30o (N or S)?
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Hadley cells
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Why is the oceans circulation important to understand climate?
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Oceans can store heat and carbon dioxide, it transports heat from the tropics to the northern hemisphere
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How does it compare to the atmospheric circulation?
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This is the large-scale movement of air and the means by which thermal energy is distributed on the surface of the earth.
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What are the drivers of the ocean circulation?
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Density differences, wind forces
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What is the Ekman transport?
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Ekman transport: explains the circulation of water currents assuming it is only driven by the transfer of momentum from the wind.
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How is Edman transport oriented with respect to the wind?
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Surface current is oriented 45 degrees of the wind and total transport is 90 degrees to the wind. In the south to the left in the north to the right.
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What would happen to climate if the Atlantic Thermohaline circulation shut down or got drastically reduced?
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No heat transport to the poles. As a result, it would extremely cold in the poles.
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What is the Thermohaline circulation (or MOC)?
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This is a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes. The adjective Thermohaline derives from thermo- referring to temprature and -haline referring to salt content, factors that together determine the density of water.
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Where is deep water formed in today's oceans?
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North Atlantic deep water, anthracic bottom water.Deep Ocean water: makes up about 90% of the volume of the oceans. Deep ocean water has a very low temperature and very high salinity.
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Why does it rain?
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Precipitation is almost always associated with the upward motion of the atmosphere.
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What is a multitude cyclone and how does it work?
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Beroclinic instability (temperature gradient, rotation)
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What does a multitude cyclone accomplish?
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Transfer heat
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What is the ocean's role in climate?
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Heat storage ; release, heat transport by the circulation, carbon dioxide (CO2) storage and release
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What is a tropical cyclone and how does it work?
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Latent heat extracted from the ocean. Transfer of heat from Upper Ocean to the atmosphere.
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Why do no tropical cyclone form near the equator?
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Because the Coriolis force is 0 and you need some Coriolis force to get it started.
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Why do we expect tropical cyclone intensity to increase as climate warms?
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When the climate warms, there is more latent heat and more latent heat creates more evaporation and more evaporation creates more cyclones.
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How much CO2 do humans emit every year?
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36 billion tons
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Why doesn't all the CO2 end up in the atmosphere?
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The ocean absorbs 25 % of the co2 and the land biosphere absorbs another large part.
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Will this absorption rate always stay the same (especially, in a warmer world?)
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No as the oceans warm up they will take in less co2
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What is the physical pump?
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Physical pump: much CO2 is dissolved in seawater
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What is the biological pump?
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Biological pump: much CO2 gets transformed into organic carbon by photosynthesis. It is the result of marine (and terrestrial) plants pulling carbon from the atmosphere and burying it away as they sink to the bottom of the ocean.
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When was the last time CO2 levels were as high as now?
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Over a million years ago
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Can weather extremes prove or disprove climate change? Why or why not?
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No what matters is the statistics of the events
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Does the weak surface temperature increase since 1998 call anthropogenic global warming into question? Why or why not?
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No because most of the heat goes into the oceans
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When do clouds form?
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When a large amount of water vapor is added to an air parcel (by evaporation from the sea surface). When cooling lowers the saturation vapor pressure to the point where air parcels become saturated.
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On average, the Hadley cell is best described by:
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Ascending motion near equator; descending motion near 30 degrees; surface easterlies
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Poleward heat transport is accomplished by:
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The Hadley cell, the wind-driven oceanic circulation, the thermohaline circulation
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Without Poleward heat transport, the equator-to-pole temperature gradient would be:
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Enhanced
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The dry adiabatic lapse rate in the atmosphere is:
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9.8 Celsius per km
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In the Northern Hemisphere, friction causes a parcel of air to move:
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Slower
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Why does anthropogenic carbon dioxide matter for climate?
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It absorbs longwave radiation and has a long residence time in the atmosphere
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Climate Change always results from:
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Long-term imbalances between incoming and outgoing radiation
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What is the main reason why the ocean is able to store so much heat?
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It is 300 times the mass of the atmosphere, its specific heat is 4 times that of dry air
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In the northern hemisphere, the Coriolis force:
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Deviates air parcels to the right
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Why is the Thermohaline circulation important for climate?
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It explains why western Europe has milder winters than Eastern Canada, it carries CO2 into the deep, removing it form the atmosphere
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Poleward of 30 degrees of latitude, most of the Poleward heat transport accomplished by:
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The ocean
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Is CO2 more or less soluble in water?
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More
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If the global ocean temperature suddenly became much colder, how would this affect its ability to act as a reservoir for CO2?
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It would be able to absorb more CO2
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As beam spreading increases, the amount of insolation (W/m2)
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decreases
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A positive feedback:
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Amplifies radiative perturbations
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What is the ultimate cause of the seasonal cycle?
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The ultimate cause of the seasonal cycle is because of variations of the amount of insolation of the earth.
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What two factors determine the amount of insolation of the earth?
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Revolution (rotation) of the earth around the sun and the tilt of the earth's axis.
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What are monsoons?
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Monsoon are seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea. They essentially work through positive feedback creating pressure gradients. They are seasonal but not perfectly regular
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How does a summer monsoon circulation work?
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In the summer land is warmer than the ocean due to their specific heat. As a result, most the atmosphere above the ocean goes towards land and vice versa. When the atmosphere of the ocean arrives at land there are clear pressure differences. As a result, it has to rain to ensure that the atmosphere becomes less dense.
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How does a winter monsoon circulation work?
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In the winter land is colder than the ocean due to their specific heat. As a result, most the atmosphere above the land goes towards ocean and vice versa. When the atmosphere of the land arrives at ocean there are clear pressure differences. As a result, it has to rain to ensure that the atmosphere becomes less dense.
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Why are monsoons important for society?
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They are important to society because provide drinking water to about 2 billion people.
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How does ENSO stand for?
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El Nino (ocean movement) + Southern Oscillation (atmospheric movement)
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How does ENSO work?
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In a normal year the trade winds blow from east to west. Blowing the warm water towards the eastern pacific, and blow the deeper colder water towards the western pacific. The fluctuation in ocean temperatures during ENSO are accompanied by even larger-scale fluctuations in air pressure between the western and eastern tropical pacific known as the Southern Oscillation.
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What happens in an El Nino year?
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In an El Nino year the trade winds are super weak, resulting in less warm water being blown to the eastern pacific. As a result, the western pacific water stays warmer and this result in further weakening of the trade winds. This causes the ocean to warm even more.
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What are the results of an El Nino on the United States and on Indonesia and Australia?
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There are wetter winters in the United States and dryer weather in Indonesia and Australia. Increases hurricanes in the pacific and lessens these in the Atlantic.
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What happens in an La Nina year?
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In a La Nina year the trade winds are super strong, resulting in more warm water being blown to the eastern pacific. As a result, the western pacific water gets colder and this result in further strengthening of the trade winds. This causes the ocean to cold even more.
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What are the results of a La Nina on the United States and on Indonesia and Australia?
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There are wetter winters in Indonesia and Australia in the southeastern United States and dryer weather in the southeastern United States. Increases hurricanes in the Atlantic and lessens these in the Pacific.
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What is its average recurrence time? Why is it called "quasi-periodic"?
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Both El Nino and the southern oscillation occur on average every 4 years. They are called quasi (semi) periodic because it reoccurs every 2 to 7 years but it does not follow an exact pattern. El Nino lasts about 1 year. La Nina can last anywhere from 1-3 years. Both phenomena are strongest from December to April.
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What are its meteorological and economic effects around the Pacific?
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El Nino has a positive impact to the eastern pacific and a negative impact to the western pacific. While, the opposite is present for La Nina.
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What is ENSO prediction based on?
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The Enso prediction is based on several variables such as satellites data, and ocean buoys. It would not be possible to predict ENSO if its dynamics weren't understood as well as they are.
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El Nino (ENSO) is the name given to:
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The leading mode of atmosphere-ocean interannual variability.
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What do Satellites provide data on as it comes to ENSO predictions?
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Satellites provide data on tropical rainfall, wind and ocean temperature patterns.
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What do ocean buoys provide data on as it comes to ENSO predictions?
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Ocean buoys help to monitor sea-surface and upper ocean temperatures.
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What does the climate system include?
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The climate system includes the oceans, land surface, cryosphere, biosphere, and atmosphere.
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What is a climate feedback?
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Climate feedbacks are processes that change as a result of a change in forcing, and cause additional climate change. An example of this is the "ice-albedo feedback." As the atmosphere warms, sea ice will melt. Ice is highly reflective, while the underlying ocean surface is far less reflective. The darker ocean will absorb more heat, getting warmer and making the Earth warmer overall. A feedback that increases an initial warming is called a "positive feedback." A feedback that reduces an initial warming is a "negative feedback." The ice-albedo feedback is a very strong positive feedback that has been included in climate models since the 1970s
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What is a climate forcing?
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A climate forcing is any influence on climate that originates from outside the climate system itself. It is defined to be anything that can alter the energy budget on top of the atmosphere. Examples of climate forcings are greenhouse gasses, volcanoes and orbital forces.
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Three major drivers of climate change:
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Mechanisms internal to the climate system (ENSO, NAO, PDO, AMO) External forcings of natural origin (Sun, volcanoes) External forcings of human (anthropogenic) origin (GHGs, aerosols)
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Cite 4 examples of positive feedbacks.
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Water-vapor feedback, Bjerknes feedback, Land-vegetation feedbacks (dust-bowl 1930s), Ice-albedo feedback
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Cite 4 examples of negative feedbacks.
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Planck's law, rock-weathering thermostat, low clouds (reflect sunlight), dimethyl-sulfide, Daisies
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How can we tell time in geology?
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For relative time dating we use stratigraphy (strata = time). For absolute time dating we use radiometric dating.
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How does stratigraphy work?
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Stratigraphy is a branch of geology which studies rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained, under the influence of gravity.
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How does radiometric dating (radiocarbon dating) work?
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The ratio of daughter to parent isotope tells you the age of the rock. The downside of this method is that it only works for 10 half-lives. That is for the reason that virtually no parent is left after 10 half-lives. We use unstable isotopes because they have the property that the decay, and therefore have a half-life.
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What is the daughter and parent isotope?
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Where, the daughter isotope is the decay product and the parent isotope is the initial product before radioactive decay.
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What are the similarities and differences between different isotopes?
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For a given element each isotope has the same number of protons (and electrons) but different number of neutrons. Where, number of protons and neutrons is equal to the mass of the isotope.
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How far back can we date an object with radiocarbon (aka 14C) and why?
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Radiocarbon dating only dates up to 40,000 - 50,000 years since it has completely decayed after 10 half lives and each half life is about 5,780 years long. This aging method assumes that radiocarbon is always being produced at the same rate as it is today.
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What type of proxy data do pale climatologists use to learn about past climates?
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Ice cores, sediment cores, corals, speleothems, tree rings
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What does the width of the growth rings tells us about the climate conditions?
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The width of growth rings is due to temperature and the available moisture
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What does the ratio of oxygen 18 to oxygen 16 (?18 O) in the ocean tell us?
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The higher the ratio, colder the current climate. This is due to the fact that the lighter elements are in the glacial ice. They also tells us about the past climate conditions.
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What are glaciers? Where are they today?
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Glaciers are large accumulations of ice on land. They are currently found in Greenland and Antarctica. Glaciers tend to accumulate ice on top of the mountain and ablate ice on the bottom of the mountain. The ice of the glacier moves down by about 1 km per year.
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How do glaciers form?
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They form in two general environments. They form at high latitudes such as Polar Regions. In addition, they form at high elevations (mountains) in even equatorial latitudes.
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How do we know if a glacier is increasing or decreasing in size?
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A glacier is increasing if ice accumulation ; ablation A glacier is decreasing if ice accumulation ; ablation
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How can we tell an area was once glaciated?
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A particular area was glaciated if there are significant signs of erosion in the mountains. Glaciers usually leave behind a particular kind of erosion called the main glacial trough.
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What is an interglacial period?
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Period for which a new ice age occurs.
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What characterizes glacial-interglacial cycles? How frequent are they?
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A glacial cycles is characterized by Glacial/interglacial occur approximately every 100,000 years.
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What do they teach us about the relationship between climate and CO2?
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The glacial maxima occur when the atmospheric Co2 levels are on its lowest at about 175 ppm. CO2 plays a significant role in ice ages through positive feedback. This happens through the physical pump.
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What are Earth's orbital parameters? What period of oscillation are they associated with?
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Precession, obliquity, eccentricity
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What is precession?
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Is a change in the orientation of the rotational axis of a rotating body. The period of oscillation is approximately 23,000 years.
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What is obliquity?
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It corresponds to the tilt of the earth's axis. The period of oscillation is 41,000 years.
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What is eccentricity?
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Describes the oblateness (flattening) of the earth's orbit around the sun. Measures departure from perfect circle with at most 6%. The period of oscillation is 98,000 years.
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What are the effects of variations in the earth's obliquity?
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The obliquity of the earth determines amount of insolation received at each latitude level. Essentially, this implies that it controls equator-to-pole differences.
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What are the effects of variations in the earth's eccentricity and precession?
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The eccentricity and precession determine amplitude of seasonal cycle. In essence, they redistribute sunlight within a year, but not amongst latitudes. The period of oscillation of the combination of these variables is 23,000 years.
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Explain the Milankovitch theory of Ice Ages
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The amount of summer insolation determines whether or not an ice sheet survives summer or melts. The amount of incoming insolation is determined by the three orbital parameters.
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When did the Last Glacial Maximum happen?
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The last glacial maximum happened about 18,000 years ago. It initially started to warm up again, but was followed by a short new ice age called the younger Dryas. This period was followed by a new warm era called the Holocene.
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What happened during the Younger Dryas?
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During the Younger Dryas (12,800 - 11,500 years ago) there rapidly evolved a new ice age. For 400 years we had almost glacial conditions.
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How did the Younger Dryas happen?
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This happened due to the fact that the Laurentide ice sheet melted and started emptying out into the Atlantic. This resulted in a dramatic reduction of deep convector in the Atlantic, and hence Thermohaline circulation.
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What happened during the Holocene?
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The Holocene is the most current interglacial period starting about 10,000 year ago. The Holocene climate optimum (HCO) is a warm period during roughly the interval of 9,000 - 5,000 years ago. It is considered the warmest moment of the current interglacial period.
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What is very remarkable about the last interglacial period?
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It is particularly remarkable how stable the temperature anomaly has been during this interglacial period. The temperature stability is widely credited for having allowed civilizations to develop.
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What happened during the deglaciation?
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During the last deglaciation, all of the ice covering North America (Laurentide Ice Sheet) melted during the period of 21,400 - 10,000 years ago. During deglaciation the temperature rise begins before carbon dioxide starts increasing.
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What's a termination?
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A termination is the action of bringing something to an end.
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What is the Ruddiman hypothesis?
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The spread of agriculture over the past 10,000 years led to large-scale deforestation, which explain the unusual rise in carbon dioxide (CO2) and Methane (CH4).
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What does the Ruddiman hypothesis have to do with the last deglaciation?
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Both carbon dioxide and methane behaved very unusual in this inter glacial period.
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What defines abrupt climate change?
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Abrupt climate change is the transition of the climate system into a different mode on a time scale that is faster than the responsible forcing. It takes place so rapidly and unexpectedly that human or natural systems have difficulty adapting to it. Abrupt climate change happens every so often.
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What are Dansgaard-Oeschger (D/O) events?
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Every abrupt climate change event is also called a Dansgaard-Oeschger (D/O) event. Abrupt climate change seems unrelated to changes in the Earth's orbital parameters. Large rapid amplitude changes seemingly unrelated to the forcings.
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What are examples of abrupt climate change?
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PETM, Dansgaard (Oeschger events), Methane clathrates, Heinrich events, Central Greenland Climate
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What happened in the abrupt climate change in central greenland?
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The local temperature increased by about 10 degrees Celsius during a 10-year timespan. This was in the period after the Younger Dryas about 11,500 years ago,
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What does anthropogenic mean?
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Anthropogenic means that something is originated from human activity. Anthropogenic global warming was first posited in 1896.
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What is the Anthropocene? When did it start?
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The Anthropocene is a new geological epoch (era), marked by a dominant human influence on the global environment. It became around the 1750 AD and is of course still going on. The Anthropocene changes appear in sedimentation, carbon cycles, climate (temperature and sea level), biota and ocean acidification.
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What important processes that could lead to abrupt climate change?
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instability of Greenland Ice sheet, atlantic deep water formation, indian Monsoon Transformation, thermohaline Circulation
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How do scientists reconstruct the climate of the past millennium?
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They use statistical relationships between climate and its proxies. So far, only variants of linear regression have been used.
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What is the Hockey Stick controversy about?
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The northern hemispheres mean annual temperatures for three of the past eight years are warmer than any other year since (at least a millennium (1000 years).
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What is special about this controversy?
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What is special about this controversy is it received a lot of political attention. In addition, there was a lot of political intimidation to get results that fit political agenda.
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When was the Little Ice Age?
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1450 - 1850 AD
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When was the Medieval Warm Period?
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900 - 1350 AD
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What is the defining feature of Medieval "megadroughts"?
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Its long duration and local existence. The possible causes are viewed to be a combination of solar and volcanic forcing with internal oscillations.
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According to Jared Diamond, what factors determine civilization collapse?
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Environmental damage (deforestation/soil erosion), climate change, hostile neighbors, friendly trade partners, society's response to problems (highly significant)
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Cite 3 civilizations whose collapse was at least partly triggered by climate change.
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Akkadian Empire, Greenland Norse, Anasazi Indians:
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How did the Akkadian Empire come to an end?
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This empire around the Middle East stated around 2334 BCE and collapsed around 2083 BCE (4098 year ago). This happened due to droughts and as a consequence failure to produce goods.
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How did the Greenland Norse come to an end?
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This empire started around 850AD (1165 years ago) and collapsed around the 1450AD (565 years ago). This is due to the following factors: environmental degradation, climate change, decline in friendly contact with Norway, highly dependent on trade with Europe, hostile contact with Inuits and their attitude itself (most vital factor) as well.
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How did the Anasazi Indians come to an end?
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This empire around Arizona and New Mexico started around 600AD (1415 years ago) and collapsed around 1200 AD because of medieval megadroughts and the population boom.
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Why does Mike Davis call late 19th century famines in India and China "Victorian Holocausts", and what role did climate play in them?
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?
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Why do Oreskes ; Conway characterize our epoch as a "Penumbra"?
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This is because there is a willful denial of scientific evidence in defense of pure ideology. Free market fundamentalism masks scientific consensus and multiple lines of evidence.
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Is glaciation overdue?
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The current orbital configuration would tend to favor ice sheet growth instead of decay. The recent rise in carbon dioxide (CO2) and Methane (CH4) appears to be responsible for this ice sheet decay.
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What are the independent signs of warming?
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Land surface temperature, tropospheric temperature, sea surface temperature, ocean heat content, marine air temperature and specific humidity, sea level, snow cover, arctic sea ice and glacier mass balance.
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Why does the IPCC call the warming of the climate system "unequivocal"?
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The IPCC calls warming unequivocal because 97/100 climate experts think humans are changing global temperature and this is supported through multiple line of evidence.
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Which parts of the Earth have warmed the most over the last 150 years?
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Parts of Southern Russia, east USA and Brazil have warmed the most. The parts that have cooled are the oceans below Florida and Greenland. It's the typical example of a loaded dice.
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Why does sea-level rise with global warming?
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This is due to the fact that the ice sheets are melting.
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What simple observation rules out that the sun could be responsible for recent global warming?
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Cold nights have become less frequent, warm nights more frequent. This can only be explained by a decrease in outgoing longwave radiation, which implies it cannot be the sun. This is due to the increase of greenhouse gasses in the atmosphere.
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What are climate models?
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A climate model incorporates physical laws, initial and boundary conditions, in order to describe the realistic evolution of climate.
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Why are they necessary?
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Modern climate models represent hundreds of physical processes and interacts, they require very large computations
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How do they work?
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Climate models incorporate a huge amount of processes and their interactions to reproduce what we experience as climate in increasingly fine detail
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What are climate models good for?
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Conceptual framework: how does radiative forcing affect surface temperature Quantification of climate change: orbital variations, greenhouse gases, volcanoes and solar activity Generating & testing hypotheses: Hindcasting (retrodiciton): looking back Forecasting: looking forward
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What disadvantage do climate have?
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Introduces errors due to uncertain forcings, processes and natural variability.
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What is equilibrium climate sensitivity (ECS) ?
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ECS is the equilibrium climate response to a doubling of carbon from 280 to 560 ppm
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What is the most likely value of ECS?
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3 degrees is the most likely value of ECS
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What are the main causes of the temperature rise since the 1950s?
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Anthropomorphic climate change
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What are 21st century climate projections based on?
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We make projections based on RCP's
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Why are these projections uncertain?
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Why are these projections uncertain? We don't have the data to back it up, different models have different sensitivities, also different variability in the climate.
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Which aspects of the climate system are projected to change with continued greenhouse emissions and how?
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Temperature (more heat waves, fewer cold nights), sea ice rise, rainfall (extremes).
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What are major sources of uncertainty in climate projections?
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Clouds (biggest source of uncertainty) RCPs, feedbacks not included, small scales.
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What do we call "committed warming"?
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Committed warming is warming that we are committed to even if we stop all emissions. There is a lag in the climate system, this makes adaptation inevitable.
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What is an ecosystem?
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An ecosystem is a system formed by the interaction of a community of organisms with their physical environment.
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Why are ecosystems important for us?
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The value of ecosystem services can sometimes be expressed in monetary terms, but these estimates are very contentious, are not the only way of expressing importance.
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What is biodiversity?
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Biodiversity is the diversity of species.
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Why does biodiversity matter for us?
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It ensures resilience of ecosystems to changes (natural or not)
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What is a mass extinction and why are biologists worried that humans are crafting the next one?
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Mass extinctions, ecosystems are collapsing and biodiversity is declining. Losing species must faster than the natural route.
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What aspects of human welfare will be negatively impacted by climate change?
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Sea-level rise, decrease in fresh water, risk of regional conflicts (food security), public health risks, increase risk of metrological disasters.
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When was CO2 first posited to warm climate? When was the first global warming calculation made?
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In 1824 CO2 was first linked to climate change, but in 1896 first time global warming calculation was made.
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When did scientific consensus began to emerge that anthropogenic global was real and potentially dangerous?
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Scientific evidence for anthropormorenc global warming happened in the 1970s
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What is the IPCC and what is its role?
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Intergovernmental Panel on Climate Change, they recommend decisions to policy makers about the change of climate.
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Why is the scientific consensus not getting through to the public?
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Media, they scheme information to get more public debate, Balance as Bias, deliberate PR campaign to confuse the public.
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What about this "controversy" steps outside of a science debate?
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It was a political debate, governmental regulation and interference, not a science debate.
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What is the "Tobacco Strategy"?
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Doubt as a political tactic to stave off government regulation.
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What is the "fairness doctrine" and how was it used in the climate controversy?
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Fairness doctrine says that the news media must represent both sides of debate, they bullied editors and outlets to have a more balanced portrayal.
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What is "balance-as-bias"?
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98% agree on climate change, the media portrays the 2% as a lot more to create public debate. Imbalance, even though there isn't much.
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What is morally reprehensible about the work of Jastrow, Nierenberg, Seitz, and Singer?
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Seitz, Jastrow, Nierenberg, Singer are all the lead architects of the climate denial movements. They all have backgrounds in physics and they used their credentials falsly.
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What is adaptation?
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Changing our behavior to better live with climate change.
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What are 3 examples of adaptation?
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Water, agriculture, Infrastructure
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What is mitigation?
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Reducing or preventing the magnitude of climate change.
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What are 5 examples of mitigation?
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Increase efficiency, change diet, reforestation, carbon storage, renewables, nuclear power
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What is Geoengineering?
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Deliberate modification of the environment to counteract the effects of global warming.
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What are 3 examples of Geoengineering?
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Ocean Fertilization (, Aerosol injection (albedo), Methadone
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What are the pros of Geoengineering?
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Easy, cheap, fast
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What are the cons of Geoengineering?
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will institute monopolies, unknown side-effects, potentially irreversible
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What is the cheapest way to stabilize global greenhouse gas emissions in the short run?
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Using energy more efficiently
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Which is the most efficient fossil fuel?
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Natural gas
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Which is the least efficient fossil fuel?
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Coal
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What are 3 examples of renewable energy sources?
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Geothermal, solar, wind
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What do we mean by sustainability?
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Meeting the needs of generation with compromising future generation's needs.
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What is a "smart grid" and why is it useful?
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Smart grid is a network of smaller grids that can heal itself, it uses information to use energy more efficiently.
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What's the link between climate, energy and water?
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All linked
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Owing to Kaya's identity, how can we decrease carbon emissions while increasing population and GDP/capita?
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Decarbonizing our economies and making them less greedy in energy.
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What did the Stern review conclude about the cost of inaction on climate change?
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Cost the world about 1-2% of the GDP to avoid the worst effects of climate change, the cost of the inaction is 20%
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Why is climate change a global policy problem?
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Impacts are diffuse, externality - cost that affects a party that didn't choose to incur that cost or benefit, the low carbon use countries are getting affected unfairly
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What are 2 examples of successfully mitigated environmental problems?
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Acid rain - solution was increased efficiency in power plants and cap ; trade system Ozone layer - solution was to replace the carbon with a substitute
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What is the Tragedy of the Commons?
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Perverse economic incentives result in destruction of the public good.
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What are the market-based policy options currently proposed for mitigation?
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Cap ; trade - government sets cap on CO2 and market decides its price, underusers can sell permits, carbon tax - price on carbon
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What are their advantages?
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Tax is easy implement
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What are their disadvantages?
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Cap ; trade is hard to implement.
