Chapter 3b Flashcards
Albedo
a measure of how much electromagnetic radiation an object reflects versus how much it absorbs
Climate change v climate system
climate change a long-term change in weather patterns on the regional and global scale climate system relationships and interactions between the atmosphere, oceans, snow,
land surfaces, and all living organisms
Energy transformation v global warming
energy transformation when energy changes from one form to another
global warming a long-term increase in the average global temperature of Earth’s climate system since the industrial revolution due to human activities
Natural disaster connection to human impact on climate change
As human impacts worsen frequency and severity of natural disasters increase
How does earths climate system balance energy transfer and change of state
Energy that enters Earth’s atmosphere comes from the Sun. For electromagnetic radiation to transform into another type of energy, such as heat, it must be absorbed by matter. The amount of absorbed energy is dependent on a planet’s albedo. Earth’s average albedo, approximately 0.30, means that 70% of the Sun’s light is absorbed.
transformation, and change of state?
Every surface has a distinct albedo between 0 and 1, see Figure 1. A surface with an albedo equal to:
• zero, is a completely black surface, absorbing all incident radiation.
One is a perfect mirror surface reflecting all incident radiation
What percent of suns electromagnetic radiation is absorbed will transfer into different forms of energy
70%
Forms of energy within earths climate system
Thermal energy
Change of state of water
Kinetic energy
Thermal energy
Impact: increase air water and ground temperature
Explanation: Hot objects re-emit their energy, transforming it back into electromagnetic radiation which transfers energy equally in all directions including out to space and back down to Earth (see ‘back radiation’ Figure 2).
Greenhouse gases provide the largest contribution to back radiation, trapping thermal energy within the atmosphere by absorbing infrared radiation emitted from the Earth’s surface (see Figure 2).
Change of state of water
Impact: evaporation of oceans and melting of ice or snow
Explanation: Energy from evaporated water is transferred into the upper atmosphere through convection to form clouds. The presence of water vapour in the atmosphere drives cloud cover and therefore rain and snow patterns including blizzards, floods, and droughts.
Water vapour in the atmosphere is a major greenhouse gas. Humid regions, such as tropical rainforests, have a large concentration of water vapour in the air, allowing them to better retain the Sun’s heat at night.
Melting of snow/ice leads to a change in global sea levels.
Kinetic energy
Impact: wind thermals underwater currents and ocean waves
Explanation: Electromagnetic energy is transformed into kinetic energy through a temperature difference between two regions, driving convection.
Waves, currents, thermals and winds transfer energy through convection in the direction they travel.
Convection currents around the world greatly impact the condition of and differences between regional climates.
Human activity impacting earths climate
Human activity is impacting climate systems in multiple ways, such as increasing greenhouse gas concentrations and changing the Earth’s albedo. As the delicate balance of energy distribution and flow changes, so too will the climate.
Precisely quantifying and predicting how the climate changes is a difficult task and
is the focus of many scientists’ research, such as those working at the Intergovernmental Panel on Climate Change (IPCC). Table 2
Earths energy Imbalance
Energy primarily enters and leaves Earth’s climate system through electromagnetic
radiation. When more energy enters than leaves, the globe’s temperature increases.
The imbalance between energy entering and leaving the Earth’s climate system
is causing a rise in average global temperatures. Many global agencies study, monitor and forecast these imbalances, as it is of fundamental concern to civilisation.
Why are global temp changing
The Sun is very hot with a surface temperature around 5530°C. According to Wien’s Law (see Lesson 3A), it emits a large amount of energy in the form of high energy, short wavelength electromagnetic radiation. Earth on the other hand is lower
in temperature, and therefore emits lower energy, longer wavelength infrared electromagnetic radiation (see Figure 3).
When incoming solar energy and outgoing Earth energy is balanced,
e) 1.0
global temperatures will remain stable. However, if incoming energy increases,
ruC Industrial
or outgoing energy decreases, there will be an energy imbalance causing warming.
ta °( revolution
rela 0.5
Global temperatures would continue to rise until the increased total energy
pmirts YRO emitted by a warmer planet is again in balance with absorbed solar energy.
etud E This can be shown by the following relationship.
nH 0
ieni- T Change in global temperatures is dependent on the difference between incoming solar energy and outgoing earth energy
Human activity contributing to climate change
Since the industrial revolution, the burning of fossil fuels causes the creation of more
Figure 4 Global temperatures over 2000 years greenhouse gases than the environment is used to. This causes more thermal energy
to be trapped in the atmosphere through back radiation thereby increasing the
MISCONCEPTION
Earth’s temperature (see Figure 4).
Global warming has increased due to many human influences, reducing the amount
‘Scientists’ measurements of global
of energy that can escape our climate system. Every individual change to our climate
temperatures are conflicting, invalid
and do not follow predictions.’
system, whether or not human caused, can be quantified as to its effects on changing global temp
