We know that climate tends to get cooler as we move away from the equator toward the poles. As the planet curves, the sun's rays cover more ground, and the sun's heat is diluted. See how the beam spreads over the slanting roof. At the equator, the sun's rays meet the planet straight on, like hitting the side of a house. The heat is more concentrated here. However, there is another way to experience climate change than going on a trip to the north or south. Temperatures also change with changes in altitude. The temperature of the atmosphere drops three degrees Fahrenheit for every 1000 feet in elevation rise.  We are pretty close to the equator here. Where the ocean meets the land there is heavy rain, and a beautiful tropical rain forest covers the ground. Next comes an area where the tropical rain forest blends into the deciduous forest. As we go up the mountain the vegetation types blend into each other, and before too long we are in a typical deciduous forest with trees that we would expect to see farther north. As the elevation continues to rise, the deciduous forest gives way to an evergreen coniferous forest. Here we find trees and bushes that we would normally see much farther north. These trees gradually become shorter and are spaced farther apart as the forest gives way to a grassy alpine biome. Here marmots whistle among the grasses and wild flowers. Eventually, grass gives way to rocks, stones, and snow. The wind is cold up here, and we are feeling the lack of oxygen in the thin air. I hope that the people in the balloon have some oxygen with them, or else are planning to come down soon. They are up where it is cold and hard to breathe! It is because of this change of temperature with altitude that high mountains are snow-capped even at the equator. © Elizabeth Anne Viau, 1999. All rights reserved. This material may be used freely for instructional purposes but not sold for a price beyond the cost of reproduction. Please inform the author if you use it at eviau@earthlink.net |
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