Library Index » Science Encyclopedia » Global Climate Change - Climate Change In Earth History, Global Warming—the Result Of Human Activity, Effects Of A Warming Climate

Global Climate Change - Climate Change In Earth History

periods lasting cold cycles

Over hundreds of millions of years, geological and astronomical forces have changed Earth's environment from hot to cold, wet to dry, and back again. Studies have shown that the climate has fluctuated between long periods of cold lasting 50,000 to 80,000 years and shorter periods of warmth lasting about 10,000 years. The Earth is in the midst of one of those warm periods now. These climate cycles are caused by tiny irregularities (known as Milankovitch Cycles) in the Earth's orbit around the sun. The climate of the past 10,000 years, during which human civilization developed, is a mere blip in a much larger history of climate change. However, human influences on the climate are significant, and effects are already being seen on species worldwide.

Global Climate Change - Global Warming—the Result Of Human Activity [next]

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