Global Warming

The earth's average temperature stays fairly much the same from year to year. It

gets very cold in the winter and very hot in the summer. Although some years may be a

little hotter than normal, it may be a little cooler where others live. Consequently, when

you look at the average temperature everywhere on the earth for a whole year, there is

very little change. The current average global temperature is about 57 degrees Fahrenheit

(14 degrees C). If there is a rise in this average temperature, then we have global warming.

In the last 100 years, the average temperature rose less than 1 degree. However, in 1995,

some say was the hottest year we have ever had, the average temperature went up half of

a degree.

On earth we get energy from the sun's light. If the sun is shining brightly on a

summer day it gets hot outside. The reason it warms up is because the earth is absorbing

solar energy. However, not all of the energy is absorbed. Some energy is reflected back

into space in the form of light. In order for our earth to stay the same temperature from

year to year, the energy arriving at the earth must be the same as the energy leaving the

earth. Therefore, if there is more energy arriving than leaving, we will have global

warming. The reason the earth could retain more energy than it gives off has to do with

the air around us and what it is made of. When wood, coal or gasoline is burned, carbon

dioxide is released. Carbon dioxide is a gas that can't be seen or smelled. If the amount of

Carbondioxide in the air goes up, the earth will heat up, which in turn is the start of global

warming.

As it gets warmer, there will be more evaporation from large bodies of water. This

increased evaporation will cause more clouds and more rainfall. Scientists are pretty

certain that there will be increased precipitation in the northern polar zone, but in other

areas they are not as sure. Some regions may actually have less rainfall than there is right

now. Higher temperatures will melt the snow earlier in the year and the land will have a

longer time to dry out. Crops that grow in these regions may not survive this added

warmth and dryness. But other changes, such as the amount of rainfall and local

temperature differences, may affect which crops will do well and which ones will not.

Some individuals think that there may be more hurricanes as a result of global warming.

However, there are so many factors that lead to tropical storms like this, that it is

uncertain what will happen.

Global warming is a constant reoccurring factor. Some say there will be an

increase in global temperatures, which is very probable. This means that the infrared

energy absorption due to the effect of all the greenhouse gases would double from what it

was. Surface atmospheric temperatures could go up 2 to 6 degrees. The rate of this rise in

temperature, will be governed by the rate at which the concentration of greenhouse gases

increases, but other factors complicate this. The most significant source of uncertainty is

the effect that clouds will have on the system. The areas that will most likely be affected

by temperature increases are the northern polar zone, where winter means temperatures

could go up about 18 degrees. In addition, the continental interiors, where significant

warming could occur. As we can see, global warming will be a factor at great in the near

future.