Climate Change
Climate change can be a worrying topic. To hear a leading scientist discuss the latest predictions for global climate change, go to Ecoshock's Interview with Dr. Andrew Weaver.
What Causes Global Warming?
The earth's climate has changed many times over its long history. Sometimes, the earth has been much warmer than it is now. Think of the dinosaurs in those steamy jungles. Sometimes, ice ages have caused most of the planet to be covered in huge continental glaciers like the one that still covers Greenland. To find out how the earth's climate has changed in the past, visit the Paleo Map Project's Paleo Climate Animation.
Now, for the first time ever, the climate of the entire planet is changing because of the activities of man. Carbon is an element, so it cannot be created or destroyed--there's a fixed amount of carbon on and around this planet. Carbon can be found in the air as carbon dioxide, or it can be stored under the earth. Living things such as trees and animals contain carbon. Sometimes, you see fossilized ferns in coal. This is because fossil fuels such as coal and oil were made from the bodies of plants and animals that died millions of years ago. We say that carbon is sequestered in the earth. That means it's been trapped there for millions of years. When we burn fossil fuels, we release that carbon into the atmosphere.
Factories, cars and even home heating all release carbon dioxide. Gradually, the amount of carbon dioxide in the atmosphere has increased. Carbon dioxide acts like a sheet of glass around the planet. As levels increase, more and more of the sun's heat is trapped in our atmosphere. This is called the greenhouse effect and it creates global warming.
Learning More About Global Warming
For an overview on global warming, visit Britain's Young People's Trust for the Environment's Global Warming Fact Sheet. For a more detailed look, here's Global Warming Facts and Our Future, from the Marian Koshland Science Museum in Washington, DC. This is an excellent resource.
Scientists can measure how much global warming is changing the earth by looking at the shrinking polar ice caps. To see how much the arctic ice is changing, visit the American National Snow and Ice Data Center's website. Loss of polar ice is important to global warming for many reasons. Ice that melts from land into the sea will cause the oceans to rise. When permafrost, land that was always frozen, starts to thaw more greenhouse gasses are released into the air. To understand how important the polar regions are to global warming, visit the article Frozen Hotbed and see the links to more articles at the bottom of that page. Frozen Hotbed comes from Pulse of the Planet the website for an American National Science Foundation daily radio program of the same name.
The CBC maintains a Climate Change News Page that covers climate change stories from many angles, and an In Depth: Climate Change page to provide more detailed stories.