Transcript Global Warming

Global
Warming
What
Is
It?
Global warming is the gradual
increase of the temperature
of the earth, which in turn
causes changes in climate.
Earth has
Warmed by about
1 degree
Farenheit over
The past 100 years.
What is Climate?
• It is the long-term
average (usually 30
years) of a
particular region’s
weather pattern.
• At the peak of the
last ice age (18,000
years ago), The
temperature was
only 7 degrees
colder than it is
today, and glaciers
covered much of
North America!
So You See…
Even a small increase in
temperature over a long time
can change the climate.
When the climate changes,
there may be big changes in
things that people depend on.
These things include the level
of the oceans and the places
where we plant crops. They
also include the air we breathe
and the water we drink.
What Might Happen to Human
Health?
Global warming may cause an increase in
heat stress and other heat related
health problems.
Ecological disturbances, air pollution,
changes in food and water supplies, and
coastal flooding may also affect human
health.
Poor people, poor countries, very young
children, and the elderly will run the
highest risks without the money and
resources needed to cope.
How will it Effect Our
Ecosystems?
• If future climate changes occur as
rapidly as predicted, an upset in the
delicate balance of rainfall, temperature,
and soil type could
seriously
endanger
many
plants and
animals and their
habitats.
What About our Sea Level?
• Global warming may make the sea
level become higher. Warmer
weather makes the glaciers melt and
adds more water to the ocean.
• Warm temperatures also make water
expand. This takes up more space
and the level of the sea rises.
• It could rise as much as 3 feet during
the next century!
• What problems could this
cause?.........
Coastal flooding could cause
saltwater to flow into areas
where salt is harmful,
threatening plants and animals
in those areas.
Flooding and beach erosion
could affect oceanfront
property and reduce the quality
of drinking water.
What about our Crops and Food
Supply?
Global warming may make the Earth
warmer in cold places, giving people in
those places a chance to grow crops
in new areas.
BUT…
It may also bring droughts to many
parts of the world. This would leave
people without enough to eat because
they couldn’t grow the food that they
need.
What is the Greenhouse
Effect?
The greenhouse effect is
what causes global warming.
It is called “greenhouse
effect” because it is the same
process that keeps the air
inside greenhouses (and parked
cars) warmer than the air
outside.
The glass in greenhouse windows is
transparent to visible light radiated from
the sun.
This light heats the surface of
materials inside the greenhouse,
which emit longer wave-length
infrared radiation.
Infrared radiation cannot
penetrate the glass and is
trapped…
Causing the inside air to
warm up.
Water vapor, clouds, carbon
dioxide, & other gasses in our
atmosphere act like the
greenhouse glass by preventing
some of the infrared radiation
emitted by the earth to escape
into space.
These are called
“greenhouse gasses”.
Where Do Greenhouse
Gasses Come From?
Volcanoes
Forest fires, crop burning,
and clearing of rain forests
Automobiles and other
internal-combustion
engines
CFCs used in refrigerators,
air conditioners and
aerosol spray cans.
Because the levels of these
gasses are increasing, more and
more of the heat radiated by the
earth’s surface is trapped in the
atmosphere…
…causing our world to heat up.
The Greenhouse Effect
• Solar
radiation
passes
through
the clear
atmosphere.
Some of the infrared radiation
Some solar
passes through the atmosphere
radiation
and some is absorbed and reis reflected by
the earth and emitted in all directions by
the atmosphere. Greenhouse gas molecules.
The effect of this is to warm
the earth’s surface and the
lower atmosphere.
Most radiation
is absorbed
by the earth’s
surface and
warms it.
The greenhouse effect is
important. Without it, the Earth
would not be warm enough for
humans to live.
But, if it becomes
Stronger, it could make
The Earth warmer than
Usual. Even a little
Extra warming may cause
Problems for humans,
Plants, and animals.
WE CAN
MAKE
A
DIFFERENCE!
Global warming may be a big
problem, but there are many
little things we can do to make a
difference.
If we try, most of us can
do our part to reduce the
amount of greenhouse
gasses that we put into
the atmosphere.
Many greenhouse gasses
come from things we do
every day.
SAVE ELECTRICITY
Whenever we use
electricity, we help put
greenhouse gases into the
air.
By turning off lights, the
television, and the
computer when you are
through with them, you can
help a lot.
BIKE
BUS
WALK
You can save energy by sometimes taking
the bus, riding a bike, or waking.
Plant Trees
It’s fun and a great
way to reduce
greenhouse
gases.
Trees absorb
Carbon dioxide
from the air.
RECYCLE
Cans, bottles, plastic bags,
and newspapers.
When you recycle, you send
less trash to the landfill and
you help save natural
resources, like trees, oil, and
elements such as aluminum.
Cars are an important part of life
for most people. But they also cause
pollution and release a lot of
greenhouse gases into the air.
Fortunately, there are some
cars that are better for the
environment…
These cars can travel longer
on a smaller amount of
gasoline. They don’t pollute
as much, either.
Using these kinds of
cars can help reduce the
amount of greenhouse
gases in the air.
Solar energy is energy that
comes from the sun.
It can be used
to heat homes,
buildings,
water, and
to make
electricity.
Today, more than 200,000 houses in the
U.S. use this type of energy.