Title: Earth's Changing Climate  | National Geographic Society
Headings: Earth's Changing Climate
Earth's Changing Climate
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Earth’s Changing Climate
Natural Causes of Climate Change
Human Causes of Climate Change
Global Warming

Content: It has a dry climate. Because climates are mostly constant, living things can adapt to them. Polar bears have adapted to stay warm in polar climates, while cacti have evolved to hold onto water in dry climates. The enormous variety of life on Earth results in large part from the variety of climates that exist. Climates do change, however—they just change very slowly, over hundreds or even thousands of years. As climates change, organisms that live in the area must adapt, relocate, or risk going extinct . Earth’s Changing Climate
Earth’s climate has changed many times. For example, fossils from the Cretaceous period (144 to 65 million years ago) show that Earth was much warmer than it is today. Fossilized plants and animals that normally live in warm environments have been found at much higher latitudes than they could survive at today. For instance, breadfruit trees, now found on tropical islands, grew as far north as Greenland.