UNITED STATES OF AMERICA

The USA is one of the largest countries in the world. It is situated in the central part of the North American continent. The area of the USA is over nine million square kilometres. It is washed by the Pa­cific Ocean and by the Atlantic Ocean. The most northern part of the USA is Alaska,, the largest state, separated from the rest of the country by Canada.

The population of the United States is nearly 250 million people, most of the people live in towns. People of different nationalities live in the USA.

The official language of the country is English. The capital of the country is Washington. It was named in honour of the first President, George Washington.

As the USA is a large country, the cli­mate is different in different regions. Foi example, the Pacific coast is a region of mild winters and warm, dry summers, but the eastern continental region is watered with rainfall. The region arounc the Great Lakes has changeable weather.

There are many mountains in the USA For example, the highest peaks of the Cordilliers in the USA are 6,193 and 4,418 metres.

The main river of the country is the Mississippi. But there are many other great rivers in the USA: the Colorado in the south and the Columbia in the north­west. There are five Great Lakes between the USA and Canada.

The USA produces more than 52 per cent of the world's corn, wheat, cotton, tobacco.

There are many big cities in the coun try. They are Washington (the capital of the country). New York (the city of contrasts, financial and business centre of the USA), Boston (there are many colleges and universities in it), Chi­cago (one of the biggest industrial cities in the USA), San Francisco, Los Ange­les, Philadelphia, Detroit (one of the biggest centres of the automobile indus­try).

The USA has an Academy of Sciences. There are many scientific institutions, museums, libraries, theatres and other interesting places in the country.

The USA is a highly developed indus­trial country. The USA is rich in mineral resources, such as aluminums, salt, zinc, coppers, and others. The country is rich in coal, natural gas, gold and silver, too. It holds one of the first places in the world for the production of coal, iron, oil, natural gas.

Such industries as machine-building, ship-building are highly developed in the country.

American agriculture produces a lot of food products: grain, fruit, vegetables.

The USA is a federal republic, consist­ing of fifty states. Each of these states has its own government. Congress is the American Parliament which consists of two Chambers.

The president is the head of the state and the government. He is elected for four years.

GLOBAL WARMING

“Global warming” has been introduced by the scientific community and the media as the term that encompasses all potential changes in climate that result from higher average global temperatures. Hundreds of scientists from many different countries are working to understand global warming and have come to a consensus on several important aspects. In general, Global warming will produce far more profound climatic changes than simply a rise in global temperature.

An analysis of temperature records shows that the Earth has warmed an average of 0.5°C over the past 100 years. This is consistent with predictions of global warming due to an enhanced greenhouse effect and increased aerosols. Part of the current global warmth is associated with the tropical El Nino, without which a record global temperature would probably not have occurred.

The Earth's climate is the result of extremely complex interactions among the atmosphere, the oceans, the land masses, and living organisms, which are all warmed daily by the sun's energy. This heat would radiate back into space if not for the atmosphere, which relies on a delicate balance of heat-trapping gases - including water vapor, carbon dioxide, nitrous oxide, and methane - to act as a natural "greenhouse," keeping in just the right amount of the sun's energy to support life.

For the past 150 years, though, the atmospheric concentrations of these gases, particularly carbon dioxide, have been rising. As a result, more heat is being trapped than previously, which in turn is causing the global temperature to rise. Climate scientists have linked the increased levels of heat-trapping gases in the atmosphere to human activities, in particular the burning of fossil fuels (coal, oil, and natural gas for heating and electricity; gasoline for transportation), deforestation, cattle ranching, and rice farming.

As the Earth's climate is the result of extremely complex interactions, scientists still cannot predict the exact impact on the earth's climate of these rising levels of heat-trapping gases over the next century. The current best estimate is that if carbon dioxide concentrations double over preindustrial levels, according to the scientific possible scenarios, an atmospheric doubling of carbon dioxide could occur as early as 2050.

In 1995, scientists with the Intergovernmental Panel on Climate Change - the authoritative international body charged with studying this issue-reached a conclusion in the Second Assessment Report, which summarizes the current state of scientific knowledge on global warming, also called climate change.

For the first time ever, the Panel concluded that the observed increase in global average temperature over the last century "is unlikely to be entirely natural in origin" and that "the balance of evidence suggests that there is a discernible human influence on global climate."

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