Contemporary World Geography
1. Briefly discuss each of the causes of climate change as presented in the film. Climate change is defined as a change in the sequence of the weather experienced at a given place. In the documentary film Earth Story: The Big Freeze, they stated that geologist before discovered that some parts of the northern hemisphere were covered in gigantic ice sheets. Scientists learned that waxing and waning of these ice sheets are the products of the warming and cooling of our climate millions of years ago. And through their study of the waxing and waning of these ice sheets as one aspect of global climatic change, they were able to point out other reasons for our planet’s change in climate. First is because of the lowing level of carbon dioxide in our atmosphere. Carbon dioxide or CO2 is a greenhouse gas that acts as a thermal blanket which keeps our planet’s surface warm. Before, they said, Earth’s temperature was much warmer. But because CO2 levels were lowering, it got cooler and cooler. And the drop was caused by some particular factor: Plants and Mountain building. When they started to evolve and flourish, that was the time when CO2 levels began to fall. Second, they noticed that the ice sheets would never accumulate if the snow of winter melts the following summer. But there are summers much cooler than the others. A cool summer will not melt all the snow, some will accumulate. So the formation of these ice sheets must’ve been from successions of cool summers. And how summers become cool or warm depends on the way that the Earth orbits the sun. Our planet circles the sun with its axis tilted. The tilt gives us our seasons. But over thousands of years, the precise orbit and the tilt of the Earth varies slightly thus making some of our summers warmer or cooler than the others. Scientists have also discovered that there were rapid flips in the climate before during glacial period. And they...
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