// lecture questions

Question 1

Independent surface (Stevenson screens and ocean
buckets) and upper air observations (balloons and satellite measurements) instrumental records all
show warming. Meanwhile other things that you would expect to change with warming are changing
in the expected sense (e.g. less glacier ice, more water vapor in atmosphere, less Arctic sea ice, less snowcover, . . . )

Answer 1

T R U E

Question 2

Forcing from greenhouse gases produced by humans
is positive and very well known, forcing from aerosols produced by humans is negative and poorly
known.

Answer 2

true (not as emphasized as first T R U E)

Question 3

We know that Human Forcing is causing a global

warming of the earth because.

Answer 3

• we know the Co2 is coming from humans
• we know it is warming
• our best models cannot produce the warming observed in the 20th century without inducing the human forcing from GHGs

Question 4

How do we know for certain that the rising CO2 in

the atmosphere is coming from Fossil fuel combustion?

Answer 4

• CO2 rises at the same time as fossil fuel combustion
• the carbon 13/12 ratio is declining: the new CO2 has the ratio you see in plants, so it must have come from fossil fuel, rather than release of CO2 from ocean water of volcanoes
• there is very little carbon-14 in the new carbon, so it has to have been buried a long time ago - fossil
• the oxygen ratio in the atmosphere is decreasing so CO2 is being added from another reservoir

Question 5

Sea level can be measured

Answer 5

• with sticks mounted to land by stuck in the ocean

- with satellites using radar altimertry

Question 6

Currently, the largest sources of sea level rise are:

Answer 6

warming of the ocean and melting of mountain glaciers

Question 7

Measuring land ice change, like Greenland, can be done with

Answer 7

gravity measurements from orbiting satellites and laser or radar altimetry from satellites or planes

Question 8

Insolation at the top of the atmosphere is less at high

latitudes that the equator because.

Answer 8

The insolation arrives at a large angle to the surface area in high latitudes and gets spread out more

Question 9

Which of the following statements is False?

Answer 9

The sky is blue because the atmosphere is cold at high altitudes. the rest are true…

• hotter objects emit more radiant energy per unit of emission area
• hotter objects emit shorter wavelength radiation
• albedo is the fraction of incident solar radiation that is reflected back

Question 10

The sun emits shorter wavelength

radiation, with more energetic photons than the Earth because

Answer 10

the sun is much hotter than earth

Question 11

The downward longwave radiation from the

atmosphere provides more Watts per square meter to the surface than the Sun.

Answer 11

true

Question 12

Solar radiation heats the surface of earth. The

largest of the three terms balancing this solar heating is.

Answer 12

Evaporation – upward turbulent flux of

wet air

Question 13

The Atmosphere warms the surface via the

greenhouse effect because:

Answer 13

The atmosphere absorbs and emits infrared radiation.

Question 14

The most important greenhouse gas is:

Answer 14

water vapor (H2O)

Question 15

The most important greenhouse gas for human-

induced climate forcing is

Answer 15

CO2

Question 16

Methane is increasing because of

Answer 16

natural gas extraction leakage and rice paddies and cow burps

Question 17

Global warming potential estimates the impact on

warming of releasing a kilogram of a greenhouse gas into the atmosphere by considering

Answer 17

• the efficiency of the molecule in absorbing IR radiation and warming the surface
• and the time that the released gas will remain in the atmosphere

Question 18

Although there are many greenhouse gases that

humans are affecting, the primary concern is with carbon dioxide (CO2) because

Answer 18

humans are likely to produce so much of it by burning fossil carbon fuels

Question 19

Doubling CO2 would produce a climate forcing of

around X Wm-2, while the solar cycle produces a climate forcing of about Y Wm-2

Answer 19

CO2 = 4Wm-2 and Solar cycle = 0.2 Wm-2

Question 20

How do Volcanic eruptions cool the climate?

Answer 20

Volcanoes injects large amounts of sulfur dioxide into the stratosphere, where it forms small sulfuric acid droplets that stay around a long time and reflect solar radiation, cooling the surface

Question 21

What are some Differences between Volcanic Eruptions and Human Volcano?

Answer 21

• volcanic eruptions are random and episodic, while the human volcano is more continuous
• volcanic eruptions are most important for climate when they spew SO2 into the stratosphere (more than 10 mi up) while the human volcano mostly only puts aerosols in the troposphere
• the most important volcanic eruptions have been tropical, whereas the human volcano is mostly northern Hem. midlatitudes
• if the human volcano stopped, its aerosol effects would be mostly gone in a couple weeks, while an explosive volcano’s emission effects climate for a couple years

Question 22

The term Global Dimming refers to:

Answer 22

The decline in observed downward solar radiation

at the ground in all the areas where it was measured during the period from the 1950’s to the 1980’s

Question 23

** water vapor feedback:

Answer 23

occurs because the lapse rate is positive and because the saturation vapor pressure increases rapidly with temp.

Question 24

Ice Albedo Feeback is greater in the Northern

Hemisphere (NH) than Southern Hemisphere (SH) because,

Answer 24

• NH has more land, more snow, and has polar ocean.

Question 25

The biggest positive climate feedback is water vapor

feedback, and the most uncertain climate feedback is cloud feedback.

Answer 25

both are true

Question 26

The great sand deserts of the Sahara and Arabia can

have annual-mean net negative radiation balance at the Top-of-Atmosphere because

Answer 26

• the surface is very hot and the air is dry
• the surface sand has a high albedo
• the atmosphere supplies the missing heat by the sinking of air

Question 27

The two largest terms in the global-mean

atmospheric energy balance are,

Answer 27

Latent heating and radiative cooling

Question 28

when you put ice in a drink it keeps cold because

Answer 28

it takes a lot of energy to melt the ice and all the ice must be melted before the water temp can rise much above 0 C.

Question 29

The two largest terms in the global-mean SURFACE

energy balance are

Answer 29

Latent cooling and radiative heating

Question 30

based on the diagram, where do you expect the ocean to be salty (where precipitation is less than evaporation)?

Answer 30

subtropics (around 30 N S)

Question 31

Potential Evapotranspiration is the amount of

evaporation plus transpiration

Answer 31

That could occur if the surface is wet

Question 32

The westerly subtropical Jet occurs

Answer 32

30N and 30S at about 12km altitude

Question 33

The Hadley Cell Transports

Answer 33

Potential energy poleward and Moisture

equatorward