Earth's Energy Balance

Question 1

What is the first law of thermodynamics?

Answer 1

Conservation of energy- energy cannot be created or destroyed only changed from one form to another.

Question 2

What is entropy?

Answer 2

• Entropy is a measure of the unavailability of a
system’s heat energy for conversion to other
forms of energy
• Lower entropy – more energy the system has
for conversion to other forms of energy
• Higher entropy – more disorganized system

Question 3

What is the second law of thermodynamics?

Answer 3

– entropy increases with time so the system becomes

more disorganized

Question 4

Distinguishing between temperature and heat

Answer 4

• Temperature – measure of the mean kinetic energy (speed) per molecule of an object (internal energy)
• Heat – measure of total kinetic energy of all the molecules of an object

Question 5

Distinguishing between sensible and latent heat

Answer 5

• Sensible heat – heat acquired by transfer from
an object of higher temperature
• Latent heat – heat acquired when a body
changes to a higher state (solid to liquid or liquid
to gas). Heat added at the change of state
doesn’t raise the temperature

Question 6

Heat transfer Processes- Conduction

Answer 6

Conduction – molecular impact without the

transfer of matter itself (heat transfer in solids)

Question 7

Heat transfer Processes- Convection

Answer 7

Convection – involves the movement of large
volumes of the substance itself (mode of heat
transfer in fluids)

Question 8

Heat transfer Processes- Radiation

Answer 8

Radiation – electromagnetic emission from a

body

Question 9

Radiation

Answer 9

• Does not require a medium to travel through
• Has both a wave structure and a particle (photon) structure
• Spectrum of wavelengths
• Radiation laws – show that the amount of radiant energy emitted by an object is much greater as temperature
increases and is wavelength dependent

Question 10

Global radiation receipt

Answer 10

Sum of all short-wave radiation received from
direct solar radiation and indirect diffuse radiation
Reflects astronomical factors and the distribution
of clouds
Shows a strong diurnal variation in intensity

Question 11

Albedo

Answer 11

A measure of the reflecting power of a

surface (reflectivity)

Question 12

The Natural Greenhouse Effect

Answer 12

• Water vapour, CO2 and other trace gases absorb
long-wave radiation emitted by the Earths surface
– re-emitting some back to Earth
• Without the natural Greenhouse Effect, the Earth
would be much colder

Question 13

Radiative forcing of climate- forcing

Answer 13

Forcing – Processes acting as external agents to the
climate system that change the energy balance – e.g.
loading of the atmosphere with aerosols (particles)

Question 14

Give examples of forcing

Answer 14

– Such forcing can occur naturally after volcanic eruptions or wildfires for example
– Aerosols scatter/reflect radiation and act as condensation nuclei promoting cloud formation
– Tropospheric sulphate aerosols slightly increase the atmospheric albedo – slight cooling effect (negative feedback)

Question 15

Radiative forcing of climate- feedback

Answer 15

Feedback – Internal agent acting in response to forcing

agents (either negative or positive)

Question 16

What is absolute zero?

Answer 16

As temperature decreases and the molecules are at complete rest where there is no internal energy, it is known as absolute zero.

Question 17

How does radiation travel?

Answer 17

Radiation does not require any medium through which to travel and so it can pass through a vacuum with the speed of light.

Question 18

What is a black body?

Answer 18

One that absorbs all the radiation falling on it and that emits, at any temperature, the maximum amount of radiant energy.

Question 19

Why is albedo important?

Answer 19

It determines the fraction of the incoming solar radiation that is absorbed by the surface.
The greater the albedo, the less solar radiation is absorbed.

Question 20

What is net radiation?

Answer 20

The difference between the total incoming and the total outgoing radiation.

Question 21

What is the effect of thermal inertia?

Answer 21

To delay the atmospheric and oceanic response to various climate forcings.

Question 22

What does the presence of thermal inertia imply?

Answer 22

That still greater climate changes will be in store for present increased atmosphere CO2 levels, which may be difficult or impossible to avoid.

Question 23

What is the primary symptom of the climate system’s thermal inertia, in the presence of increasing greenhouse gas concentrations?

Answer 23

An imbalance between the energy absorbed and emitted by the planet.

Question 24

What did Hansen (2005) discover?

Answer 24

Using a climate model, driven mainly by increasing human-made greenhouse gases and aerosols, among other forcing that the sun is now absorbing 0.85 +/- 0.15 W m-2 more energy from the sun than it is emitting to space.

Question 25

What is the imbalance between the energy absorbed and emitted by the planet confirmed by?

Answer 25

Precise measurements of increasing ocean heat content over the past 10 years.
This implies an expectation of additional global warming of about 0.6oC without further change of atmospheric composition.

Question 26

IPCC Working Group 1, Fourth Assessment Report (2007a) estimated that..

Answer 26

a further 0.6oC unavoidable warming by the end of the century relative to 1980-1999 even if atmospheric greenhouse levels remain at 2000 levels.

Question 27

IPCC Working Group 2, Fourth Assessment Report (2007b) commented that…

Answer 27

this leads to the conclusion that there are some impacts for which adaptation is the only available and appropriate response.

Question 28

What is lost and gained in terms of radiation in the atmosphere?

Answer 28

The atmosphere loses more heat to space in the form of long wave radiation than it gains from the absorption of short wave radiation, and this is the equivalent to a cooling of 1 or 2 degrees per day.

Question 29

What is the majority of the heat lost to space in long term radiation?

Answer 29

The latent heat released by atmospheric water vapour that has evaporated from the surface, condensing to form precipitation.

Question 30

What maintains the mean equilibrium atmospheric temperature?

Answer 30

A balance between radiative cooling and condensational heating.

Question 31

Radiation has

Answer 31

a wave and a particle structure

Question 32

Incoming radiation from the sun is predominantly

Answer 32

shortwave

Question 33

• Radiation laws –

Answer 33

show that the amount of radiant energy emitted by an object is much greater as temperature increases and is wavelength dependent