Global warming just appeared as a serious environmental
problem, during the last decade. Global warming is the subject of
a lot of debate. Global warming is defined as the warming of the
earth by the green house gasses admitted into the atmosphere
naturally or by man kind.Many people even question whether or not global warming
even exists.

And many people that believe gobal warming does
exist, question why it exists. There is one fact that no one has
questioned, the surface temperature of the earth has increased
0.45 - 0.6 degrees in the past century.

Global warming has been proven and disproven many times
using computer climate models. Believers in global warming use
them to show that in the next century there will be a significant
rise in the earths temperature. The nonbelievers in global
warming suggest that the models arent based entirely on fact.And they cant be trusted.Surface analysis has shown that the surface temperature of
the earth has increased dramatically over the past century because
of the admission of green house gasses.

The fear is that the
earths temperature will continue to increase. This may eventually
cause the ice caps to melt, the sea levels to rise, and this will
cause the worlds coast line to be washed away.Global warming will make many changes on crops and
plants. In the mid latitudes the amount of moisture in the soil will
probably decrease in the summer. Higher temperatures will melt
the snow earlier in the year and the land will have a longer time
to to dry out. Crops that grow in these regions may not survive
this added warmth and dryness.

Other changes such as the
amount of rain fall and local temperature differences, may effect
which crops do well and which ones dont. But scientists arent
certain what will happen in each region.According to some studies winter in the polar zones could
be 18 degrees warmer. This increase in temperature could cause
sea ice to melt which can result in a rise of sea level , but how
much it will rise is not clear. Some scientists dont think there will
be any global warming in the polar areas.

Global warming will also change the amount of
precipitation. As it gets warmer, there will be more evaporation
from large bodies of water. This increased evaporation will cause
more clouds and more rain fall. Scientists are almost certain that
there will be increased precipitation in the northern polar zone,
but in other areas they are not as sure.Some scientists think that there will be more hurricanes as a
result of global warming.

However there are so many factors that
lead to tropical storms, it is uncertain what will happen. Scientists
also think that certain diseases will become more wide spread.One of these is Malaria which is spread by mosquitoes. Some
scientists say that an additional 20% of the worlds population
will live in areas where they can get Malaria.

The skeptics of global warming believe that global warming
isnt a environmental problem. They think that the recent increase
in the earths temperature is no cause for alarm. And they believe
that the earths coast lines and polar ice caps arent in danger of
disappearing. They believe that the climate models used to prove
global warming and to predict effects are misrepresented. They
point out that according to the models last century should have
been a lot worse than it was. They also point out that temperature
increases occurred before wide spread emission of carbon dioxide
in the middle of the 20th century.

They say that most higher
temperature readings are taken in cities or airports where
temperatures are higher.