lunes, 11 de abril de 2011

GLOBAL WARMING

Cause of global warming

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. The largest contributing source of greenhouse gas is the burning of fossil fuels leading to the emission of carbon dioxide. When sunlight reaches Earth’s surface, some is absorbed and warms the earth and the rest is radiated back to the atmosphere at a longer wave- length. Some of these longer wavelengths are absorbed by greenhouse gases in the atmosphere before they are lost in the space. The absorption of this 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 in space. The reflecting back of heat energy by the atmosphere is called the “greenhouse effect”.

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.


SPEAKING ACTIVITY
Answer these questions and discuss them with your classmates.

a. What global warming effects do you suffer in your every day life?
________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
b. Do you contribute to global warming effects?
______________________________________________________________________
c. Do you think people are responsible of global warming?
____________________________________________________________________________________________________________________________________________
d. What country in your opinion contributes the most to global warming?
____________________________________________________________________________________________________________________________________________
e. What natural disasters will be side effects of global warming?
________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

GRAMMAR TIP
1st conditional
Used to express situations based on fact in the present or future (things that may happen)

If clause    will / won’t    main clause
Examples:
If he comes late I’ll be angry.
We won’t sleep if you don’t arrive

Complete these sentences.
If I don’t clean my house…………………………………………………………………
If I have an exam tomorrow………………………………………………………………
If I spend all my money…………………………………………………………………
If I make a delicious dinner……………………………………………………………..
If my friends asks me for help…………………………………………………………..
If I lose all my school notes……………………………………………………………..
If nobody comes to my party…………………………………………………………….


Match conditions and results and make complete sentences.

CONDITIONS
a. If we raise our voice
b. If we choose efficient vehicles
c. If we drive smart cars
d. If we drive less
e. If we buy energy efficient appliances
f. If we replace light bulbs with fluorescent bulbs
g. If we weatherize our homes

RESULTS
_______ We’ll produce less carbon oxide.
_______ We´ll make the authorities listen to us.
_______ We´ll save a lot of electricity.
_______ We´ll reduce air pollution.
_______ We´ll reduce the burning fossils fuels.
_______ We´ll have better fuel efficiency.
_______ We´´ll save on buying light bulbs.

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