*~*~Global Warming~*~*

-GLOBAL WARNING-

What Causes Global Warming?

Scientists have spent decades figuring out what is causing global warming. The only way to explain the pattern is to include the effect of greenhouse gases emitted by humans.

One of the first things scientists learned is that there are several greenhouse gases responsible for warming, and humans emit them in a variety of ways-

The most come from the combustion of fossil fuels in cars, factories and electricity production. The gas responsible for the most warming is carbon dioxide, also called CO2. Other contributors include methane released from landfills and agriculture, nitrous oxide from fertilizers, gases used for refrigeration and industrial processes, and the loss of forests that would otherwise store CO2.

Different greenhouse gases have very different heat-trapping abilities. Some of them can even trap more heat than CO2. A molecule of methane produces more than 20 times the warming of a molecule of CO2. Nitrous oxide is 300 times more powerful than CO2. Other gases, such as chlorofluorocarbons, have heat-trapping potential thousands of times greater than CO2. But because their concentrations are much lower than CO2, none of these gases adds as much warmth to the atmosphere as CO2 does.

In order to understand the effects of all the gases together, scientists tend to talk about all greenhouse gases in terms of the equivalent amount of CO2. Since 1990, yearly emissions have gone up by about 6 billion metric tons of "carbon dioxide equivalent" worldwide, more than a 20% increase!

What effects does this have on Earth?
The planet is warming, from North Pole to South Pole, and everywhere in between. Globally, the mercury is already up more than 1 degree Fahrenheit (0.8 degree Celsius), and even more in sensitive polar regions. Signs are appearing all over Earth!

Some impacts from increasing temperatures are already happening.

• Ice is melting worldwide, especially at the Earth’s poles
• The decline of penguins on Antarctica have fallen from 32,000 breeding pairs to 11,000 in 30 years
• Sea level rise became faster over the last century.
• Some butterflies, foxes, and alpine plants have moved farther north
• Precipitation has increased across the globe
• Spruce bark beetles have boomed in Alaska and chewed up 4 million acres of spruce trees

Other effects could happen later this century, if warming continues-

• Sea levels are expected to rise between 7 and 23 inches
• Hurricanes and other storms are likely to become stronger
• Plants could bloom earlier than their pollinating insects become active
• Floods and droughts will become more common
• Less fresh water will be available
• Some diseases will spread, such as malaria carried by mosquitoes
• Ecosystems will change—some species will move farther north or become more successful; others won’t be able to move and could become extinct

www.environmentnationalgeographic.com

Global warming solutions...continued in my next blog