Global warming is described as the increase in the average temperature of the air situated close to the Earth’s surfaces, as well as the oceans throughout the world
3. Global
warming, the
phenomenon
of increasing
average air
temperatures
near the
surface
of Earth over
the past one
to two
centuries.
Climate scientists have since
the mid-20th century gathered
detailed observations of
various weather phenomena
(such as temperatures,
precipitation, and storms) and
of related influences on climate
(such as ocean currents and the
atmosphere’s chemical
composition).
These data indicate that Earth’s
climate has changed over
almost every conceivable
timescale since the beginning
of geologic time and that the
influence of human activities
since at least the beginning of
the Industrial Revolution has
been deeply woven into the
very fabric of climate change.
4. Almost 100% of the observed temperature increase over
the last 50 years has been due to the increase in the
atmosphere of greenhouse gas concentrations like water
vapour, carbon dioxide (CO2), methane and ozone.
Greenhouse gases are those gases that contribute to the
greenhouse effect (see below). The largest contributing
source of greenhouse gas is the burning of fossil fuels
leading to the emission of carbon dioxide.
CAUSES OF GLOBAL WARMING
5.
6. When sunlight reaches Earth's surface some is absorbed and
warms the earth and most of the rest is radiated back to the
atmosphere at a longer wavelength than the sun light.
Some of these longer wavelengths are absorbed by
greenhouse gases in the atmosphere before they are lost to
space.
The absorption of this long wave radiant energy warms
the atmosphere.
These greenhouse gases act like a mirror and
reflect back to the Earth some of the heat energy
which would otherwise be lost to space.
7. The reflecting back of heat energy by
the atmosphere is called the
"greenhouse effect".
The major natural greenhouse gases are
water vapour, which causes about 36-70%
of the greenhouse effect on Earth (not
including clouds); carbon dioxide CO2, which
causes 9-26%; methane, which causes 4-9%,
and ozone, which causes 3-7%.
It is not possible to state that a
certain gas causes a certain
percentage of the greenhouse
effect, because the influences of
the various gases are not additive.
Other greenhouse gases
include, but are not limited
to, nitrous oxide, sulphur
hexafluoride,
hydrofluorocarbons, per
fluorocarbons and
chlorofluorocarbons.
8. Global warming causes by greenhouse effect
Greenhouse gases in the atmosphere (see above)
act like a mirror and reflect back to the Earth a
part of the heat radiation, which would
otherwise be lost to space. The higher the
concentration of green house gases like carbon
dioxide in the atmosphere, the more heat energy
is being reflected back to the Earth. The emission
of carbon dioxide into the environment mainly
from burning of fossil fuels (oil, gas, petrol,
kerosene, etc.) has been increased dramatically
over the past 50 years, see graph below.
: Cause for global warming: Carbon dioxide emissions in million
tons per year over the last 200 years. (graph taken
fromhttp://www.globalwarmingart.com/wiki/Image:Global_Carbo
n_Emission_by_Type_png)
9. Global warming cause: Concentration of carbon dioxide
has dramatically increased in the last 50 years (Source:
NOAA)
10.
11. From which sectors do the
major greenhouse gas
emissions come from? The
lower part of the picture
shows the sources individually
for the gases carbon dioxide,
methane and nitrous oxide,
respectively. (Graph from
http://en.wikipedia.org/wiki/I
mage:Greenhouse_Gas_by_S
ector.png)
12. Effects of global warming
There are two major effects of global warming:
Increase of temperature on the earth by about 3° to
5° C (5.4° to 9° Fahrenheit) by the year 2100.
Rise of sea levels by at least 25 meters (82 feet) by
the year 2100.
15. Each year, scientists learn more about the consequences of global
warming, and many agree that environmental, economic, and health
consequences are likely to occur if current trends continue.
16. Melting glaciers, early snowmelt, and severe droughts will cause more dramatic
water shortages and increase the risk of wildfires in the American West.
17. Rising sea levels will lead to coastal flooding on the Eastern
Seaboard, especially in Florida, and in other areas such as the
Gulf of Mexico.
18. •Forests, farms, and cities will face troublesome new pests, heat waves, heavy
downpours, and increased flooding. All those factors will damage or destroy
agriculture and fisheries.
19. Disruption of habitats such as coral reefs and Alpine meadows could drive many
plant and animal species to extinction.
21. 1. Speak up!
“Talk to your friends and family, and make sure
your representatives are making good decisions
By voicing your concerns—via social media or, better yet, directly to
your elected officials—you send a message that you care about the
warming world.
Encourage Congress to enact new laws that limit
carbon emissions and require polluters to pay for the
emissions they produce.
22. 2. Power your home with renewable energy.
Choose a utility company that
generates at least half its power
from wind or solar and has been
certified by Green-e Energy, an
organization that vets
renewable energy options. If
that isn’t possible for you, take
a look at your electric bill; many
utilities now list other ways to
support renewable sources on
their monthly statements and
websites.
23. 3.Reduce water waste
Saving water reduces carbon pollution,
too. That's because it takes a lot of
energy to pump, heat, and treat your
water. So take shorter showers, turn off
the tap while brushing your teeth, and
switch to WaterSense-labeled fixtures
and appliances.
24. 4. Buy better bulbs
LED light bulbs use up to 80 percent less energy
than conventional incandescent. They’re also
cheaper in the long run: A 10-watt LED that
replaces your traditional 60-watt bulb will save
you $125 over the light bulb's life.
25. 5. Drive a fuel-efficient vehicle.
Gas-smart cars, such as
hybrids and fully electric
vehicles, save fuel and
money. And once all cars
and light trucks meet 2025’s
clean car standards, which
means averaging 54.5 miles
per gallon, they’ll be a
mainstay.
26. 6. Pull the plug(s).
Taken together, the outlets in your home are likely powering
about 65 different devices – an average load for a home in the
U.S. Audio and video devices, cordless vacuums and power
tools, and other electronics use energy even when they're not
charging.
This "idle load" across all U.S. households adds up to the output
of 50 large power plants in the U.S. So don't leave fully charged
devices plugged into your home's outlets, unplug rarely used
devices or plug them into power strips and timers, and adjust
your computers and monitors to automatically power down to
the lowest power mode when not in use.
