What is Global Warming?
Scientists
believe the Earth's average temperature has risen slightly in the last few
decades.
For about the last 10,000 years, the average temperature the
Earth has been about 15°Celsius (59° Fahrenheit). During this time, the Earth's average
temperature has not changed by more than 1°C (1.8°F). Scientists can
now document that the average temperature of the Earth has risen about 0.5°C
(0.8°F) since 1850. Additionally, the 1990’s were the warmest decade
ever recorded. Scientists predict that the Earth will warm 1.0° to
3.5°C (1.8° to 6.3°F) in the next 100
years. This appears to be the more rapid and greater warming of Earth's
temperature than has ever occurred.
What is causing Global Warming?
Many factors contribute to the Earth's temperature, including
the shape of the Earth's revolution around the Sun, the Earth's tilt on its
axis, the way the Earth wobbles on its axis, solar activity such as sun spots,
and the chemical composition of Earth's atmosphere. Scientists believe that
human activities are affecting the chemical composition of Earth's atmosphere.
How are human activities affecting Global
Warming?
Earth's atmosphere is 78 percent nitrogen and 21 percent oxygen.
Less than one percent of the atmosphere is carbon dioxide, water vapor,
methane, nitrogen oxides, and ozone, which are known as greenhouse
gases. Greenhouse gases act like the panes of glass in a greenhouse. They
keep some of Earth's heat from escaping to space. Until about 100 years ago,
the concentration of greenhouse gases in Earth's atmosphere was stable.
Scientists believe that human activities are changing the concentration of
greenhouse gasses in Earth's atmosphere. Specifically, they are concerned about
how much carbon dioxide, methane, and nitrogen oxides are being added to the
atmosphere as a result of human activities. Just like adding an extra blanket
to your bed will keep you warmer, more greenhouse gases will keep the planet
warmer.
What might be the consequences of Global
Warming?
Minor changes in Earth's temperature have resulted in dramatic
changes for life on Earth. As little as a 3° to 5° C
(5.5° to 9.0° F) decrease in Earth's
temperature have resulted in Ice Ages. Scientists are concerned because they do
not know what a similar change in the opposite direction might cause. They do
feel confident that a warmer planet may not necessarily mean a more comfortable
planet. Some changes that may occur include: a rise in sea level, stronger
storms and where they occur, a change in where foods can be produced, and
stress on plants that will not have had enough time to adapt.
How can we reduce the impact of Global
Warming?
The most important thing people can do to reduce the impact of
global warming is to reduce the amount of greenhouse gases they add to the
atmosphere. This means we must reduce our use of fossil fuels. This means
driving less and using the most energy efficient appliances available. We must
also wisely choose what land will be developed for houses and other
construction. Land that is developed reduces the amount of vegetation present.
Vegetation takes carbon dioxide out of the air, so less vegetation means more
carbon dioxide will remain in the atmosphere.
