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IB 12
1
Energy, Power and Climate Change
Degraded energy: energy transferred to the surroundings that is no longer available to do
work – can’t be converted into other forms
Examples: thermal energy due to friction, sound, energy of deformation
Second Law of Thermodynamics:
1) The total entropy of the universe is increasing.
2) No cyclical process (engine) is ever 100% efficient. Some energy is transferred
out of the system (lost to the surroundings) as unusable energy (degraded energy).
Sankey diagrams (energy flow diagrams) are used to keep track of energy transfers and
transformations in any process.
1) Thickness of arrow is proportional to amount of energy.
2) Degraded energy points away from main flow of energy.
3) Total energy in = total energy out.
Sankey diagram
for a flashlight:
Sankey diagram for
a car engine:
Sankey diagram for
an electric motor:
See Hamper p. 171
Thermal energy can be
completely converted to work in a
single process.
Example: isothermal expansion
Q = ∆U + W
∆U = 0 so Q = W
A continuous conversion of
thermal energy into work
requires a cyclical process.
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Type of fuel Renewable? CO2 emissions?
Fossil fuels No Yes
Nuclear No No
Hydroelectric Yes No
Wind Yes No
Solar Yes No
Wave Yes No
Power Generation in a typical electrical power plant
1. Some fuel is used to release thermal energy – coal, natural gas, oil, uranium
2. Thermal energy is used to boil water to make steam.
3. Steam turns turbines attached to coils of wire.
4. Coils of wire turning a magnetic field induce alternating potential difference.
5. Potential difference is stepped up for transmission in order to reduce I2R loss of power
in lines.
Fossil fuels: coal, oil, natural gas
Origins of fossil fuels: organic matter decomposed under conditions of high temperature and
pressure over millions of years
Non-renewable fuels: fuels that cannot be replaced as fast as they are used as so will be used
up will run out eventually – limited supply of resource
Renewable fuels: resource that cannot be used up (permanent) or is replaced at same rate as
being used
World Energy Sources
Other energy sources: biofuels, tidal, geothermal
NOTE: In most instances . . . the Sun is the prime energy source for world energy.
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Fuel Energy Density
(MJ/kg) Fusion fuel 300,000,000
Uranium-235 90,000,000
Gasoline (Petrol) 46.9
Diesel 45.8
Biodiesel 42.2
Crude oil 41.9
Coal 32.5
Sugar 17.0
Wood 17.0
Cow dung 15.5
Household waste 10
Energy density of a fuel: the ratio of the energy released from the fuel
to the mass of the fuel consumed
Units: J/kg
Use: to compare different types of fuels
How is choice of fuel influenced by energy density?
Fuels with higher energy density cost less to
transport and store
Other considerations: cost of production, political,
social and environmental factors
The energy released by one atom of carbon-12 during combustion is approximately 4 eV. The
energy released by one atom of uranium-235 during fission is approximately 180 MeV.
a) Based on this information, determine the ratio of the energy density of uranium-235 to
that of carbon-12. 2.3 x 10
6
b) Based on your answer above, suggest one advantage of uranium-235 compared with
fossil fuels.
Higher energy density implies that uranium will produce more energy per
kilogram – less fuel needed to produce the same amount of energy
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Fossil Fuel Power Production
Historical and geographical reasons for the widespread use of fossil fuels:
1. industrialization led to a higher rate of energy usage (Industrial Revolution)
2. industries developed near large deposits of fossil fuels (coal towns)
Transportation and storage considerations:
1. Natural gas is usually transported and stored in pipelines.
Advantages: cost effective
Disadvantages: unsightly, susceptible to leaks, explosions, terrorist activities, political
instability (withholding use of pipelines or terminals based for political reasons)
2. Many oil refineries are located near the sea close to large cities. Oil is transported via ships,
trucks, and pipelines.
Advantages: workforce and infrastructure in place, easy access to shipping
Disadvantages: oil spills and leakage, hurricanes, terrorist activities
3. Power stations using coal and steel mills are usually located near coal mines.
Advantages: minimizes shipping costs
Disadvantages: environmental impact (strip mining), mine cave-ins
Use of fossil fuels for generating electricity
Advantages: Disadvantages:
1. high energy density
2. relatively easy to transport
3. cheap compared to other sources
4. can be built anywhere
5. can be used in the home
1. combustion produces pollution, especially SO2 (acid
rain)
2. combustion produces greenhouse gases (CO2)
3. extraction (mining, drilling) damages environment
4. nonrenewable
5. coal-fired plants need large amounts of fuel
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Fossil
Fuel
Typical
Efficiency
Coal 35%
Natural Gas 45%
Oil 38%
2. State the energy transformations in using fossil fuels to
generate electrical energy:
Chemical energy in fuel….thermal energy in
steam…rotational mechanical energy/kinetic
energy…electrical energy in turbines…
At each stage energy is dissipated in thermal/sound energy
3. Sketch a Sankey diagram for a typical fossil fuel power plant.
1. State typical efficiencies for fossil fuel
power generating plants:
4. An oil-fired power station produces 1000 MW of power.
a) How many joules of energy will be produced in one day?
b) How much energy is released from the fuel per day?
c) What is the rate of oil consumption by the plant per day?
Use efficiency
Use energy
density
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5. A 250 MW coal-fired power plant burns coal with an energy density of 35 MJ/kg. Water enters
the cooling tower at a temperature of 293 K and leaves at a temperature of 350 K and the water
flows through the cooling tower at a rate of 4200 kg/s.
a) Calculate the energy removed by the water each second. 1000 MW
b) Calculate the energy produced by the combustion of coal each second. 1250 MW
c) Calculate the overall efficiency of the power station. 20%
d) Calculate the mass of coal burned each second. 35.7 kg
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World Fuel Consumption
The histogram shows the relative proportions of world use of
the different types of energy sources that are available,
though it will vary from country to country. This shows their
use for all purposes, such as manufacture, transportation,
electric power generation, heating, etc.
Most oil and natural gas is used for manufacture of
plastics, pharmaceuticals and other synthetic materials.
They are also used for transportation fuels. The next
biggest use is for production of electricity. The pie chart
below shows the relative use of each type of fuel to
generate electricity.
Nuclear Energy
Source: fissioning of uranium-235 and conversion of mass into energy
Sketch a Sankey
diagram for a typical
nuclear power plant.
State the energy transformations in using nuclear fuels to generate electrical energy:
Nuclear energy in fuel….thermal energy in coolant . . thermal energy in heat exchanger/steam…rotational
mechanical energy/kinetic energy…electrical energy in turbines…
Comparing Nuclear Fuel to Fossil Fuel
Advantages:
1. No global warming effect – no CO2 emissions
2. Waste quantity is small compared with fossils fuels
3. Higher energy density – 1 kg of uranium releases more
energy than 1 kg of coal
4. Larger reserves of uranium than oil
Disadvantages:
1. Storage of radioactive wastes
2. Increased cost over fossil fuel plants
3. Greater risks in an accident (due to
radioactive contamination)
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Solar Power
Solar heating panel (active solar heater): converts light energy from Sun into thermal
energy in water run through it
Photovoltaic cell (solar cell): converts light
energy from Sun into electrical energy
Use: heating and hot water Use: electricity
The amount (intensity) of sunlight varies with:
a) time of day
b) season (angle of incidence of sunlight – altitude of Sun in sky – Earth’s distance from Sun)
c) length of day
d) latitude (thickness of atmosphere)
Which way should a solar panel or cell be facing in the Northern hemisphere? Why?
South to receive Maximum radiation from the sun to provide maximum energy for whole day
Advantages:
1. Renewable source of energy
2. Source of energy is free
3. No global warming effect – no CO2 emissions
4. No harmful waste products
Disadvantages: 1. Large area needed to collect energy
2. Only provides energy during daylight
3. Amount of energy varies with season,
location and time of day
4. High initial costs to construct/install
Advantages of solar heating panel over solar cell: requires less (storage) area, less cost, more
efficient
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1. An active solar heater whose efficiency is 32% is used to heat 1400 kg of water from 200 C to 50
0 C. The average power
received from the Sun in that location is 0.90 kW/m2.
a) How much energy will the solar heater need to provide to heat the water?
b) How much energy will be needed from the Sun to heat the water?
c) Calculate the area of the solar heater necessary to heat the water in 2.0 hours.
2. A photovoltaic cell with an area of 0.40 m2 is placed in a position where the intensity of the Sun is 1.0 kW/m
2.
a) If the cell is 15% efficient, how much power does it produce?
b) If the potential difference across the cell is 0.50 V, how much current does it produce?
c) Compare placing 10 of these solar cells in series and in parallel.
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3. Why is it impossible to extract all power from air?
a) Speed of air cannot drop to zero after impact with
blades
b) Frictional losses in generator and turbulence
around blades
4. Why are turbines not placed near one another?
a) Less KE available for next turbine
b) Turbulence reduces efficiency of next turbine
Wind Power
Basic features of a horizontal axis wind turbine:
a) Tower to support rotating blades.
b) Blades that can be rotated to face into the wind.
c) Generator.
d) Storage system or connection to a distribution grid.
Energy transformations:
Solar energy heating Earth . . . Kinetic energy of air . . .
kinetic energy of turbine . . electrical energy
1. Determine the power delivered by a wind generator:
23
length of cylinder of air =
volume of air
through turbines per second =
mass of air
d = vt
= = Av
= =
through
turbines per second =
power delivered to
turbines by air =
Av
1/ 2 1
2
V Ad
t t
m V
t t
KE mvA v
t t
ρρ
ρ= =
2. Reasons why power formula is an estimate:
a) Not all KE of wind is transformed into
mechanical energy
b) Wind speed varies over course of year
c) Density of air varies with temperature
d) Wind not always directed at 900 to blades
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1. A wind turbine has blades 20 m long and the speed of the wind is 25 m/s on a day when the air density is 1.3 kg/m3.
Calculate the power that could be produced if the turbine is 30% efficient.
2. A wind generator is being used to power a solar heater pump. If the power of the solar heater pump is 0.50 kW, the
average local wind speed is 8.0 m/s and the average density pf air is 1.1 kg/m3, deduce whether it would be
possible to power the pump using the wind generator.
Advantages:
1. Renewable source of energy
2. Source of energy is free
3. No global warming effect – no CO2 emissions
4. No harmful waste products
Disadvantages:
1. Large land area needed to collect energy since
many turbines are needed
2. Unreliable since output depends on wind speed
3. Site is noisy and may be considered unsightly
4. Expensive to construct
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Hydroelectric Power
A third scheme is called pumped storage. Water is pumped to a high reservoir during the night when the
demand, and price, for electricity is low. During hours of peak demand, when the price of electricity is
high, the stored water is released to produce electric power. A pumped storage hydroelectric power plant is
a net consumer of energy but decreases the price of electricity.
A second scheme, called tidal water storage, takes advantage of big
differences between high and low tide levels in bodies of eater such
as rivers. A barrage can be built across a river and gates, called
sluices, are open to let the high-tide water in and then closed. The
water is released at low tide and, as always, the gravitational potential
energy is used to drive turbines to produce electrical energy.
There are many schemes for using water to generate
electrical energy. But all hydroelectric power schemes
have a few things in common. Hydroelectric energy is
produced by the force of falling water. The
gravitational potential energy of the water is
transformed into mechanical energy when the water
rushes down the sluice and strikes the rotary blades of
turbine. The turbine's rotation spins electromagnets
which generate current in stationary coils of wire.
Finally, the current is put through a transformer where
the voltage is increased for long distance transmission
over power lines.
By far, the most common scheme for harnessing the
original gravitational potential energy is by means of
storing water in lakes, either natural or artificial,
behind a dam, as illustrated in the top picture at right.
Energy transformations:
Gravitational PE of water . . . Kinetic energy of water . . . kinetic energy of turbine . . electrical energy
Advantages:
1. Renewable source of energy
2. Source of energy is free
3. No global warming effect – no CO2 emissions
4. No harmful waste products
Disadvantages:
1. Can only be utilized in particular areas
2. Construction of dam may involve land being
buried under water
3. Expensive to construct
IB 12
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1. A barrage is placed across the mouth of a river at a tidal
power station. If the barrage height is 15 meters and
water flows through 5 turbines at a rate of 100 kg/s in
each turbine, calculate the power that could be produced
of the power plant is 70% efficient. 2.6 x 104W
Use average height for EP = mgh
2. A reservoir that is 1.0 km wide, 2.0 km long and 25
meters deep is held behind a dam. The top of this
artificial lake is 100 meters above the river where the
water is let out at the base of the dam. Assume the
density of water is 1000 kg/m3.
a) Calculate the energy stored in the reservoir.
4.3 x 1013
J
b) Calculate the power generated by the water if it flows at a rate of 1.0 m3 per second through the turbine.
875 kW
IB 12
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Wave Power
Energy can be extracted from water waves in many ways.
One such scheme is shown here.
Oscillating Water Column (OWC) ocean wave energy
converter:
1. Wave capture chamber is set into rock face on land
where waves hit the shore.
2. Tidal power forces water into a partially filled
chamber that has air at the top.
3. This air is alternately compressed and decompressed
by the “oscillating water column.”
4. These rushes of air drive a turbine which generates
electrical energy.
Energy transformations:
Kinetic energy of water . . . Kinetic energy of air . . . kinetic energy of turbine . . electrical energy
Determining the power per unit length of a wavefront
2 2
2
A2
V= A2
mgh
volume of shaded region =
mass of shaded region =
potential energy of shaded region =
power per wave =
power per unit length for a w
= A2
A1 12
2 2
e =1
av2
P
L
L
LgA
LgAE
A Lg A LgvT T T
A
λ
λρ ρ
λρ
λρ λ
ρ ρ = = =
gvρ
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Advantages:
1. Renewable source of energy
2. Source of energy is free
3. No global warming effect – no CO2 emissions
4. No harmful waste products
Disadvantages:
1. Can only be utilized in particular areas
2. High maintenance due to pounding of waves
3. High initial construction costs
1. If a wave is 3 meters high and has a 100 meter wavelength and 0.1 Hz frequency, estimate
the power of each meter of the wavefront. 114 kW per meter
2. Waves of amplitude 1.5 meter roll onto a beach at a rate of one every 12 seconds with a speed
of 10 m/s. Calculate:
a) how much power they carry per meter of shoreline
b) the power along a 2 km stretch of beach.
IB 12
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Black-Body Radiation
Black-body radiation: radiation emitted by a “perfect” emitter
When heated, a low-pressure gas will . . .emit a discrete spectrum
When heated, a solid will . . . emit a continuous spectrum
This means that an object that acts as a black body will . . . perfectly absorb all incoming radiation and
not reflect any then perfectly radiate it.
Emission Spectra for Black-Bodies
1. Not all wavelengths of light will be emitted with equal
intensity.
2. Wavelength with highest intensity is related to . . .
temperature.
3. As body heats up, wavelength at which most power is
radiated . . . decreases.
4. Area under curve is proportional to . . . total power
radiated by body
Your Turn
Use the axes at right to sketch the emission
spectra for a black-body radiating at low
and high temperature. Be sure to label the
axes and indicate which curve represents
which temperature.
Stefan-Boltzmann Law: relates intensity of radiation to temperature of body
4
4
4
I T
PT
A
P AT
σ
σ
σ
=
=
=
8
2 4
where =Stefan-boltzmann constant
=5.67 x 10 W
m K
σ
σ −
The total power radiated by a black-body per unit area is proportional to the fourth power of the
temperature of the body.
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1. The average temperature of the surface of the Sun is approximately 5800 K. Calculate the total intensity of the
radiation emitted by the Sun.
2. The average radius of the Sun is 7.0 x 108 m. Calculate the total energy radiated by the Sun each second.
3. How much energy does the Sun radiate each hour?
Emissivity (e) – ratio of power emitted by an object to the
power emitted by a black-body at the same temperature.
4. Calculate the power emitted by a square kilometer of ocean surface at 100C.
4
BB
BB
Pe
P
P eP
P e ATσ
=
=
=
IB 12
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Solar Radiation
Calculate the intensity of the Sun’s radiation incident on Earth.
4
2 4
2
(4 )
4
S
S
PI
A
A TI
A
R TI
r
σ
σ ππ
=
=
=See pg. 3 of data booklet for 1.5 x 10
11 m
State some assumptions made in the above calculation.
1. Orbit is a perfect sphere.
2. Sun and Earth are perfect spheres.
3. No radiation is absorbed by atmosphere.
4. Sun and Earth are perfect black bodies.
Solar Constant: the amount of solar energy that falls per second on an area of 1 m2 above the earth’s
atmosphere at right angles to the Sun’s rays
Accepted value: 1380 W/m2
Average incoming solar radiation:
Accepted value: = ¼ solar constant =340 W/m2
Power incident on a disc of area πr2 and averaged over a
sphere of area 4 πr2
IB 12
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Albedo – ratio of total solar radiation power scattered by a planet to total solar radiation received
by a planet
Meaning: fraction of the total incoming solar radiation received by a planet that is reflected
back out into space
Global annual mean albedo on Earth: 0.30 = 30%
The Earth’s albedo varies daily and is dependent on:
1. season
2. cloud formations
3. latitude
Greenhouse Effect –
a) Short wavelength radiation (visible and short-wave infrared) received from the Sun causes the Earth’s
surface to warm up.
b) Earth will then emit longer wavelength radiation (long-wave infrared) which is absorbed by some gases in
the atmosphere.
c) This energy is re-radiated in all directions (scattering). Some is sent out into space and some is sent back
down to the ground and atmosphere.
d) The “extra” energy re-radiated causes additional warming of the Earth’s atmosphere and is known as the
Greenhouse Effect.
Incoming solar radiation: 340 W/m2
Radiation reflected (by atmosphere, clouds,
ground): 0.30 (340) =100 W/m2
Radiation absorbed (by atmosphere, clouds,
ground): 0.70 (340) = 240 W/m2
Total energy reflected and re-emitted by Earth:
340 W/m2 since in thermal equilibrium
IB 12
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Greenhouse Gases: each has natural and man-made origins
1. Carbon Dioxide (CO2): product of photosynthesis in plants, product of fossil fuel combustion
2. Methane (CH4): product of decay and fermentation and from livestock, component of natural gas
3. Water Vapor (H2O): evaporation
4. Nitrous Oxide (N2O): product of livestock, produced in some manufacturing processes
Enhanced (Anthropogenic) Greenhouse Effect – Human activities have released extra carbon dioxide
into the atmosphere, thereby enhancing or amplifying the greenhouse effect.
Major cause: the burning/combustion of fossil fuels
Possible effect: rise in mean sea-level
Outcome: climate change and global warming
Absorption of infrared radiation by greenhouse gases
Resonance – a transfer of energy in which a system
is subject to an oscillating force that matches the
natural frequency of the system resulting in a large
amplitude of vibration
Application to the greenhouse effect:
The natural frequency of oscillation of the
molecules of the greenhouse gases is in the
infrared region
Transmittance/Absorbance Graphs for
Greenhouse Gases
IB 12
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2. Calculate the expected equilibrium temperature of the Earth.
4
2
solar radiation absorbed = radiation emitted
(.70)340
255
WT
m
T K
σ=
=
4. The measured equilibrium temperature of the Earth is 288 K. Comment on why this is greater than the temperature
calculated above.
significant amounts of energy is trapped in atmosphere to warm up Earth to 288 K by GHE
Surface Heat Capacity (CS) – energy required to raise the
temperature of a unit area of a planet’s surface by 1 K.
S
QC
A T=
∆
Formula: Units:
2
J
m K
Using a simple energy balance model to predict the heating of a planet
Temperature change formula:
S
S
QC
A T
P tC
A T
=∆∆
=∆
( )
( )
in outS
in out
S
I I tC
T
I I tT
C
− ∆=
∆− ∆
∆ =
Surface heat capacity of Earth: CS = 4.0 x 108 J m
-2 K
-1
1. Explain, using a simple energy balance model, that the intensity of the energy re-radiated by the Earth is about 340 W/m2.
If the Earth is at thermal equilibrium, then it is emitting energy at the same rate that it is absorbing it. Average incoming
solar radiation intensity is 340 W/m2 so radiated intensity is also 340 W/m
2.
3. State two assumptions made in the model used above.
a) assumed Earth is a black-body radiator - not true – Emissivity is <1
b) neglected the greenhouse effect
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5. Use the measured equilibrium temperature of Earth to determine the emissivity of Earth.
4
2
8 4
solar radiation absorbed = radiation emitted
(.70)340
240 (5.67 x 10 )(288)
0.62
We T
m
e
e
σ
−
=
=
=
6. Suppose a change causes the intensity of the radiation emitted by Earth to decrease 10%.
a) Suggest a mechanism by which this might happen.
Increased amounts of greenhouse gases cause more solar radiation to be trapped in atmosphere
b) Calculate the new intensity of radiation emitted by Earth. 0.90(340) = 306 W/m2
c) Calculate the amount by which earth’s temperature would rise over the course of a year as a result.
8
( )
(340 306)(365)(24)(3600)
4.0 x 10
2.7
in out
S
I I tT
C
T
T K
− ∆∆ =
−∆ =
∆ =
d) State some limitations of the model used in the calculation above.
1. treats the planet as a whole and ignores interactions between parts (eg. Between oceans and
atmosphere)
2. ignores feedback mechanisms (eg. Increase in temperature may melt ice caps which would reduce
albedo of earth)
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Global Warming
Possible models suggested to explain global warming:
1. changes in the composition of greenhouse gases may increases amount of solar radiation
trapped in Earth’s atmosphere
2. increased solar flare activity may increase solar radiation
3. cyclical changes in the Earth’s orbit may increase solar radiation
4. volcanic activity may increases amount of solar radiation trapped in Earth’s atmosphere
Global Warming: records show that the mean temperature of Earth has been increasing in recent years.
Global mean surface temperature anomaly
relative to 1961–1990
In specific terms, an increase of 1 or more Celsius degrees in a period of
one hundred to two hundred years would be considered global warming.
Over the course of a single century, an increase of even 0.4 degrees
Celsius would be significant. The Intergovernmental Panel on Climate
Change (IPCC), a group of over 2,500 scientists from countries across the
world, convened in Paris in February, 2007 to compare and advance
climate research. The scientists determined that the Earth has warmed .6
degrees Celsius between 1901 and 2000. When the timeframe is advanced
by five years, from 1906 to 2006, the scientists found that the temperature
increase was 0.74 degrees Celsius.
In 2007, the IPCC report stated that:
“Most of the observed increase in globally averaged temperature since the mid-20th century is
very likely due to the increase in anthropogenic [human-caused] greenhouse gas concentrations.”
(the enhanced greenhouse effect)
Major likely cause of the enhanced greenhouse effect: increased combustion of fossil fuels
Evidence linking global warming to increased
levels of greenhouse gases
International Ice Core Research: Between 1987 and 1998,
several ice cores were drilled at the Russian Antarctic base at
Vostok, the deepest being more than 3600 meters below the
surface. Ice core data are unique: every year the ice thaws and
then freezes again, forming a new layer. Each layer traps a small
quantity of the ambient air, and radioactive isotopic analysis of
this trapped air can determine mean temperature variations from
the current mean value and carbon dioxide concentrations. The
depths of the cores obtained at Vostok means that a data record
going back more than 420,000 years has been built up through
painstaking analysis.
Inspect the graphical representation of the ice core data and draw a conclusion.
There is a correlation between Antarctic temperature and atmospheric concentrations of CO2
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Mechanisms that may increase the rate of global warming
1. Global warming reduces ice and snow cover, which in turn reduces the albedo. This
will result in an increase in the overall rate of heat absorption.
2. Temperature increase reduces the solubility of CO2 in the sea and increases
atmospheric concentrations.
3. Deforestation results in the release of more CO2 into the atmosphere due to “slash-
and-burn” clearing techniques, as well as reduces the number of trees available to
provide “carbon fixation.”
4. Continued global warming will increase both evaporation and the atmosphere’s ability
to hold water vapor. Water vapor is a greenhouse gas.
5. The vast stretch of permanently frozen subsoil (permafrost) that stretches across the
extreme northern latitudes of North America, Europe, and Asia, also known as tundra,
are thawing. This releases a significant amount of trapped CO2.
Coefficient of Volume Expansion (β) – fractional
change in volume per degree change in temperature
o
V
V Tβ
∆=
∆
Formula: Units:
1
K
Rise in sea-levels
As the temperature of a liquid rises, it expands. If this is applied to water, then as the average
temperature of the oceans increases, they will expand and the mean sea-level will rise. This has
already been happening over the last 100 years as the sea level has risen by 20 cm. This has had an
effect on island nations and low-lying coastal areas that have become flooded.
Precise predictions regarding the rise in sea-levels are hard to make for such reasons as:
1. Anomalous expansion of water: Unlike many liquids, water does not expand uniformly.
From 00C to 4
0C, it actually contracts and then from 4
0C upwards it expands. Trying to
calculate what happens as different bodies of water expand and contract is very difficult, but
most models predict some rise in sea level.
2. Melting of ice: Floating ice, such as the Arctic ice at the North Pole, displaces its own
mass of water so when it melts it makes no difference. But melting of the ice caps and
glaciers that cover land, such as in Greenland and mountainous regions throughout the
world, causes water to run off into the sea and this makes the sea level rise.
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Possible solutions for reducing the enhanced greenhouse effect
1. Greater efficiency of power production.
To produce the same amount of power would require less fuel, resulting in reduced CO2 emissions.
2. Replacing the use of coal and oil with natural gas.
Gas-fired power stations are more efficient that oil and coal and produce less CO2.
3. Use of combined heating and power systems (CHP).
Using the excess heat from a power station to heat homes would result in more efficient use of fuel.
4. Increased use of renewable energy sources and nuclear power.
Replacing fossil fuel burning power stations with alternative forms such as wave power, solar power, and wind power would
reduce CO2 emissions.
5. Carbon dioxide capture and storage
A different way of reducing greenhouse gases is to remove CO2 from waste gases of power stations and store it underground.
6. Use of hybrid vehicles
Cars that run on electricity or a combination of electricity and gasoline will reduce CO2 emissions.
International efforts to reduce the enhanced greenhouse effect
1. Intergovernmental Panel on Climate Change (IPCC): Established in 1988 by the World
Meteorological Organization and the United Nations Environment Programme, its mission is not to
carry out scientific research. Hundreds of governmental scientific representatives from more than
100 countries regularly assess the up-to-date evidence from international research into global
warming and human induced climate change.
2. Kyoto Protocol: This is an amendment to the United Nations Framework Convention on Climate
Change. In 1997, the Kyoto Protocol was open for signature. Countries ratifying the treaty
committed to reduce their greenhouse gases by given percentages. Although over 177 countries
have ratified the protocol by 2007, some significant industrialized nations have not signed,
including the United States and Australia. Some other countries such as India and China, which
have ratified the protocol, are not currently required to reduce their carbon emissions.
3. Asia-Pacific Partnership of Clean Development and Climate (APPCDC): This is a non-treaty
agreement between 6 nations that account for 50% of the greenhouse emissions (Australia, China,
India, Japan, Republic of Korea, and the United States.) The countries involved agreed to
cooperate on the development and transfer of technology with the aim of reducing greenhouse
emissions.
