The Greenhouse effect The Greenhouse effect Global warmingGlobal warming MethaneMethane The Polar ice caps will melt within 4 yearsThe Polar ice caps will melt within 4 years Polar bearsPolar bears Oil in the North PoleOil in the North Pole

THE GREENHOUSE EFFECT

When the sunrays travel through the earth’s atmosphere and reach the planet, the earth’s surface absorbs the solar energy.

In the atmophere are present gases like carbon dioxide, nitrous oxide, methane and ozone which trap the energy from the sun and prevent the heat from escaping back into space.

The use of aerosols, hairspray cans, fridges, etc., produces a group of highly dangerous greenhouse gases called chlorofluorocarbons.

The main cause of global warming is a layer of gases like carbon dioxide and methane that have the effect of cushioning the earth.

The radiation we get from the sun is absorbed in the atmosphere, but, when the layer of gases becomes very thick, the radiations cannot escape and are absorbed in this layer.

So the earth’s surface gets warmer and warmer.

GLOBAL WARMING

METHANE

Methane is one of the main greenhouse gases. It is present in nature in the form of gas and comes from the combustion of the things on earth. In recent years its concentration in the atmosphere has significantly increased contributing to global warming.

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One of the world's leading

experts has predicted the ice melting of the Arctic Ocean during the summer months, within the next four years. A global disaster is unfolding before our eyes. Each year, the area of sea ice that melts is getting bigger and bigger, overcoming any fatal prediction. We must act immediately to reduce the planet temperature, caused by what we call «global warming», if we want to survive. In 2007 the ice surface was reduced to 4.17 million square kilometres. This year, the ice area will not reach 3.5 million.

Included in the red list of endangered animals, polar bears run a big risk of becoming extinct, so, by 2050, as many as 75% of their already small population could definitely disappear!

THE STRUGGLE FOR SURVIVAL OF POLAR BEARS

Without ice polar bears struggle to find food and are obliged to continuous movements with their puppies, so they often fail to survive, due to their hard work and effort.While wandering in search for food, bears come close to the mainland, then to villages, thus running the risk of being killed by man.

• The threat comes from oil The threat comes from oil companies, too. The melting companies, too. The melting of the Arctic ice makes it of the Arctic ice makes it much more accessible and much more accessible and vulnerable to exploitation: vulnerable to exploitation: first inaccessible areas are first inaccessible areas are now targeted by oil now targeted by oil companies with their ships companies with their ships and platforms currently and platforms currently jeopardizing the already jeopardizing the already menaced and weakened menaced and weakened ecosystem.ecosystem.

Rosati Licio FrancescoRosati Licio Francesco2^A2^A

Liceo Scientifico “G. Galilei” (PE)Liceo Scientifico “G. Galilei” (PE)a.s. 2012/2013a.s. 2012/2013

English Teacher: Prof.ssa Miscia English Teacher: Prof.ssa Miscia RobertaRoberta