Do
you like warm weather? Do you wish it could be warmer still? Be careful what
you wish for. The Earth may be moving in that direction. The trend is called
global warming.
Not all scientists agree that global warming is
happening. Some say it is impossible to know if the climate is changing
overall.
After all, temperatures vary from day to day and year to year. Most scientists, however, say the trend is up. The warmest days are warmer, the coldest days not as cold.
They point out that the ten warmest years of the last century happened after 1980. The three hottest came after 1990. The hottest year on record was 1998.
After all, temperatures vary from day to day and year to year. Most scientists, however, say the trend is up. The warmest days are warmer, the coldest days not as cold.
They point out that the ten warmest years of the last century happened after 1980. The three hottest came after 1990. The hottest year on record was 1998.
These scientists say the Earth has warmed up about 1°
Fahrenheit (0.6° Celsius) in the last 100 years. The rate of change, they say,
is speeding up. A hundred years from now, the Earth may well be as much as ten
degrees hotter!
People
are changing the atmosphere. The changes started hundreds of years ago when
people began cutting down forests and burning the wood.
The invention of cars and other machines greatly increased the amount of greenhouse gases released into the atmosphere.
Such machines burn fuels like wood, coal, oil, and natural gas. When these fuels burn, they add carbon dioxide to the atmosphere. Methane comes from producing coal.
The invention of cars and other machines greatly increased the amount of greenhouse gases released into the atmosphere.
Such machines burn fuels like wood, coal, oil, and natural gas. When these fuels burn, they add carbon dioxide to the atmosphere. Methane comes from producing coal.
Today, the air contains almost one-third more
carbon dioxide than it did in 1750. The amount of methane has doubled.
Global
warming could melt the ice at the poles. This would raise the level of the
oceans. Water would then cover all the flat coastal lands. People would have
less land on which to live and grow food.
Plants and animals are adapted to their climates. If
the climate changes rapidly, many may not be able to adapt. Some species will
simply die out. Others may spread to cooler climates. There, however, they will
be struggling with species already in place.
Burning
less wood, coal, oil, and natural gas will help stop global warming. Scientists
recommend that people get more energy from sunlight, wind, tides, nuclear
energy, and other sources that don’t burn fuel. Energy sources like these put
little or no greenhouse gases into the air.
Scientists say trees can help prevent global
warming. All growing plants take carbon dioxide out of the air. Trees do this
especially well. They turn the carbon part of carbon dioxide into wood. They
release the oxygen. In recent years, people have been cutting down forests all
over the world. Scientists say vast new forests must be planted.
Source: Encarta
