CLIMATE CHANGE
1. Describe what climate change is.
2. Describe the natural greenhouse effect.
3. Give examples of evidence that our
climate has changed.
CLIMATE CHANGE
CLIMATE CHANGE QUIZ
Click on the image above and try out the quiz on
climate change and the earth’s natural process of
regulating carbon dioxide.
CLIMATE CHANGE
1. Describe the natural greenhouse effect.
OZONE LAYER
The earth’s atmosphere is made up of several
layers. One of these is the ozone layer. The ozone
layer or ozone shield refers to a region of Earth's
stratosphere that absorbs most of the Sun's UV
radiation. It contains high concentrations
of ozone (O3) relative to other parts of the
atmosphere, although it is still very small relative to
other gases in the stratosphere.
GREENHOUSE GASES
Natural greenhouse gases are found in
the atmosphere and are essential in
keeping the earth warm and habitable.
The natural greenhouse gases absorb
the heat instead of it escaping into
space.
It is called the
natural greenhouse
effect because, just
like a greenhouse,
it allows the Sun’s
heat to become
trapped.
CLIMATE CHANGE
1. Describe the natural greenhouse effect.
The ozone layer is the part of the upper
atmosphere where ozone is found in the
highest concentrations. The ozone there
absorbs ultraviolet radiation, preventing
most of it from reaching the ground. This
is important because ultraviolet radiation
can lead to skin cancer.
The destruction of the thin ozone
layer allows solar radiation to
enter our atmosphere.
CLIMATE CHANGE
1. Describe the natural greenhouse effect.
• The atmosphere is a mixture
of oxygen (21%), nitrogen
(78%), carbon dioxide
(0.037%) and other gases
such as hydrogen, helium,
argon, neon, krypton, xenon
and ozone. It also contains
water vapour.
• Only some of the gases in the
atmosphere are greenhouse
gases – they help to keep the
earth warm.
There are four main layers
in the atmosphere.
CLIMATE CHANGE
1. Describe the natural greenhouse effect.
Global Heat Budget
• The earth is heated by the
sun.
• When the Earth heats up it
releases heat energy.
• Some of the heat is
absorbed by greenhouse
gases rather than escaping
back into space.
• This keeps the earth warm
and is called the natural
greenhouse effect.
CLIMATE CHANGE
1.
Describe the discovery of the OZONE HOLE
OZONE HOLE
In May 1985 scientists with the British Antarctic Survey
shocked the world when they announced the discovery
of a huge hole in the ozone layer over Antarctica.
Their data, collected at the Halley Research Station in
Antarctica, suggested that CFCs were to blame. That's
because atmospheric conditions during the cold, dark,
Antarctic winters were building stockpiles of CFCs over
the South Pole.
The ozone hole sits on top of the Antarctic
continent and its discovery resulted in the
1987 Montreal Protocol agreement
to ban CFC’s which were commonly used in
fridges, spray cans and insulation foam.
Click on the image to watch a short NASA video
that discusses the decreasing size of the hole.
Click on the image above to view
today’s status of the ozone layer
over the Antarctic with a focus
upon the ozone hole. (Nasa.gov)
Video Question: explain why levels of ozone rise and fall.