Transcript BIOLOGY FORM 4 CHAPTER 9

• Green house effect is an important natural process.
• Without it, the Earth would be too cool for the survival of living
organisms.
• Carbon dioxide is the main green house gas.
• But…human activities had released more green house gases to the
atmosphere. CFC, methane, nitrous oxide and ozone.
• The green house effect. Will increase the Earth temperature
• This phenomenon known as GLOBAL WARMING.
Other things we do send greenhouse gases into the air too;
• The trash that we send to landfills produces a greenhouse gas called methane.
• Whenever we drive or ride in a car, we are adding greenhouse gases to the
atmosphere.
• When factories produce things that we buy and use everyday, they too are
sending greenhouse gases into the air.
Earth has been warmed by about 1ºF (0.6 °C) over the past 100 years.
And way this happened?
Global Warming: Global warming refers to an average increase in the
Earth's temperature, which in turn causes changes in climate.
The Greenhouse Effect: Greenhouse gases make the Earth warmer by
trapping energy in the atmosphere.
Have you ever seen a greenhouse?
1. The sun heats up the Earth. Some
of the sun’s solar rays bounce off
of the Earth’s atmosphere and
return to outer space. Some make
it all the way to the surface of the
Earth.
2. The rays that reaches the Earth warm
the Earth. When the Earth is warm,
it radiates its own rays of heat, called
infrared rays. Some of these rays
escape to outer space.
3. Others are absorb by gases called
“greenhouse gases” which radiate
heat. Greenhouse gases allow the
earth to be in just the right temperature
for life.
4. Higher concentrations of carbon dioxide
and other "greenhouse" gases (methane,
nitrous oxide, ozone and water vapor) trap
more infrared energy in the atmosphere
than occurs naturally. The additional heat
further warms the atmosphere and Earth’s
surface.
Sometimes little things can turn into big things.
Human Health
• Climate changes may affect people's health both directly and indirectly.
Ecological Systems
• Alter the world's habitats and ecosystems – all living things.
Sea Level Rise
• Global warming may make the sea level become higher.
Crops and Food Supply
• cold places - chance to grow crops in new areas.
• warm places - bring drought.
When the Earth temperature is increase,
It will cause the melting of the ice sea.
This phenomenon, will increase the sea
level.
Can you imagine what will happen if the
ice still melt year by year??
The Majuro Atoll
If sea level rises 20 inches then 80% of
the Majuro Atol will be under water.
Many other islands may also be
submerged if sea level rises. (Photo
courtesy of the National Oceanic and
Atmospheric Administration/Department
of Commerce)
Coral Bleaching
The algae in this coral died giving it a
bleached appearance. (Photo courtesy of
the National Oceanic and Atmospheric
Administration/Department of
Commerce)
Disappearing Ice Packs
Warmer temperatures could affect the
wildlife the artic regions because of the
melting of the sea ice. Native peoples in
these areas depend on the ice berg to
hunt seals and walruses.
Increased Air Pollution
Air pollution in high-density cities can be a
health hazard to individuals with asthma.
Photochemical pollutants tend to increase
with warmer temperatures.
Global warming may be a big problem, but there are many little things we
can do to make a difference.
1.Governments can adopt a range of options for reducing greenhouse gas
emissions, including
•encouraging the use of renewable energy sources (such as wind and solar power)
•eliminating subsidies that encourage the use of coal and oil by making them
artificially cheap
•protecting and restoring forests, which serve as important storehouses of carbon
2.Individuals can reduce the need for fossil fuels and often save money by
•driving less and driving more fuel-efficient and less-polluting cars
•using energy-efficient appliances
•using less electricity in general