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        October 23, 2007

(CNN Student News) -- October 23, 2007 Planet in Peril: Climate Change LLOYD: We're wrapping up our Planet In Peril series today with a report on climate change. An environmental studies professor at Stanford University says, "there's no way there's anything natural that can explain it." A professor of atmospheric sciences at MIT says, it's part of the natural warming and cooling a planet goes through. They're talking about transitions in the earth's temperature, something Carl Azuz now boils down to the basics. (BEGIN VIDEO CLIP) CARL AZUZ, CNN STUDENT NEWS: In a world that's always changing, there's one thing that many folks want to stay the same: the temperature. A change of just a couple degrees, can make a world of difference, and not necessarily a good one. The Earth's average temperature fluctuates, going through both warming and cooling periods. The last cooling off period was between 1945 and 1975. Since then, though, things have been steadily heating up. And most scientists point to Arctic ice melting as proof; something Anderson Cooper saw firsthand. ANDERSON COOPER, CNN ANCHOR: Already in the last 30 years, at least 400-thousand square miles of sea ice has melted. That's about the size of Texas and California combined. And as the ice melts it affects sea levels around the world, which impacts tens of millions of people. AZUZ: What's controversial about climate change is whether people have anything to do with it. A change in the Earth's orbit or the sun's radiation could cause global warming. But so could an increase in greenhouse gases. The Earth needs these gases to maintain a warm, livable environment. But they contain carbon dioxide, which has increased dramatically over the last couple centuries. This may be due to car emissions, burning fossil fuels, deforestation. Many scientists blame all of it for causing the world to warm up. But is it all just theory, another planetary 'summer' before 'fall,' or are we headed for severe drought, consuming fires and melted ice caps? Carl Azuz, CNN, Atlanta. (END VIDEO CLIP)

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