Global warming, Детальна інформація

Global warming

Introduction in 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.

A recent study by an international panel of scientists suggested that if trends in current emissions of greenhouse gases and aerosols continue, the globe may warm by an average of 2°C by the year 2100. The average rate of warming would probably be greater than any seen in the last 10,000 years

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. Yet, it could also be within acceptable limits for natural temperature variation. The twelve warmest years of the twentieth century have occurred since 1980. The Earth’s warmest years since 1861 have been: 1981, 1983, 1987, 1988, 1989, 1990, 1991, 1994, 1995, 1996, 1997 and

1998. 1997 and 1998 were the two warmest years recorded during that period.

This lends support to the assumption that the Earth’s climate is warming.

However, it may take another decade of continued increases in global temperatures to provide conclusive evidence that the world’s climate is warming as a result of the enhanced greenhouse effect.

Global surface air temperature in 1997 was warmer than any previous year this century, marginally exceeding the temperature of 1995. Part of the current global warmth is associated with the tropical El NiЯo, without which a record global temperature would probably not have occurred.

Global surface temperatures in 1998 set a new record for the period of instrumental measurements, report NASA/GISS researchers who analyzed data collected from several thousand meteorological stations around the world.

The global temperature exceeded that of the previous record year, by such a wide margin that the 1998 calendar year is certain to also set a new record. The United States experienced in 1998 its warmest year in the past several decades. As for the Russia, global surface air temperatures in 1997-

98 were not warmer than previous years.

Until recently, researchers were uncertain whether Climate developments reflected natural variations in the Earth, or whether in fact human activities contributed to the warming. The latest observed data reveals some striking trends:

- All 10 of the warmest years on record have occurred in the last 15 years.

- The 1990s have already been warmer than the 1980s - the warmest decade on record - by almost 0.2°F (0.1°C), according to the Goddard Institute of

Space Studies.



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- The global average surface temperature has risen 0.5°-1.1°F (0.3°-0.6°C) since reliable records began in the second half of the 19th century.

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."

The Cause

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.

But Global Warming has received much press in the past decade. There are many questions like these ones. Could the earth’s climate really heat up?

What are the causes if such a warming occurs? Is global warming a theory and thrue or false theory at that?

These questions and more are what climate scientists are asking themselves daily. So, there are two sides to every story and both are discussed in the media.

The Impacts