climate change and effect on the world

What is Global Climate Change?

Greenhouse gases keep

our planet warm. They

exist naturally in the

atmosphere, heating it

by trapping energy that

has originally come from

the Sun. This process is

called the greenhouse

effect. Without the

greenhouse gases the surface of the Earth would be as

cold as the surface of the Moon (about -18 degrees

Celsius or °C). In fact the typical surface temperature

of the Earth is about 15°C.

Changing Temperatures

Measurements taken from all over the world, however,

have shown that the global climate is changing. In the

last 100 years the atmosphere has warmed up by about

half a degree Celsius.

Also during this time humans have been emitting extra

greenhouse gases, which are the result of burning fossil

fuels (like coal, oil and gas). These gases include carbon

dioxide, methane and nitrous oxide.

Greenhouse Gases

It is thought that the man-made emissions of

greenhouse gases, from the increased use of fossil

fuels, are responsible for some of the warming of the

global climate during the 20th century. The extra

greenhouse gases in the atmosphere trap more energy

and therefore enhance the greenhouse effect. This may

cause more warming. Greenhouse gases are also released

by the exhausts of motor vehicles. The cutting down of

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rain forests also releases carbon dioxide, which is a

greenhouse gas and causes global warming.

Natural Changes

There are also natural ways in

which the climate can be altered.

Volcanoes release gases, which

mix with water vapour in the air

to make aerosols, and cool the

atmosphere. Changes in the Sun's energy and the

circulation of the ocean also affect climate.

The Future

If the Earth continues to warm as climate models have

predicted, the temperature at the Earth's surface may

be 3°C warmer by 2100 than it is today. This rapid

change in temperature would be harmful to many

ecosystems, and many species of plants and animals.

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The Effects of Global Warming ON SEA LEVEL :

inconvenient truth

Warmer Seas and Melting Ice

When the Earth warms, the oceans

will warm and expand causing an

increase in the level of the sea. This

process is thought to be responsible

for about a quarter of the sea level

rise recorded during the 20th century.

The melting of ice sheets in Greenland

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and Antarctica could be another major cause, although it

is not known what contribution this makes.

According to many studies, sea levels have been rising by

1-2 millimetres (mm) each year for the past 100 years.

Current predictions suggest that the sea level may rise

by half a metre in the next 100 years.

Flooding

Higher sea levels will threaten the low-lying coastal

areas of the world such as the Netherlands and

Bangladesh. Many important fisheries would become

threatened and coastal ecosystems damaged.

In Britain, East Anglia and the

Thames Estuary will be particularly at

risk from flooding as sea levels

increase.

Scientists agree that global warming will generally result

in milder winters and hotter summers, although there

will be differences between countries. In winter it may

rain more, but in the summer, it may become dryer.

Water resources would generally benefit from wetter

winters but warmer summers with longer growing

seasons and increased water evaporation would put

greater pressure on them.

Changing Evaporation and Rainfall

Water is essential for

human life and development.

Much of the world's

agricultural, hydroelectric

power and water supplies

depend upon the water cycle.

The Effects of Global Warming on Water Resources:

Global warming will affect the water cycle, placing

stress on water resources.

In some areas of the world water evaporation may

increase by a greater amount than rainfall. This would

lead to lower water levels in rivers and lakes. Global

warming may mean that rainfall becomes concentrated

into large storms that could cause problems with

flooding.

Hydroelectric Power

Water is used for a number of different purposes that

will be affected by global warming. Rivers may become

prone to flooding or drought. Hydroelectric power

generation depends upon a high water flow to make

electricity. If flows decrease, less hydroelectric power

will be generated. The supply and demand for water to

homes and workplaces may also be affected if the levels

of reservoirs and aquifers decrease.

Looking after future water resources with care will

become increasingly important as global warming takes

place.

climate change and effect on the world

Friday, December 10, 2010

climate change and effect on the world: http://www.youtube.com/watch?v=ntOjGVRimPc&feature...

GLOBAL WARMING