Continental Drift
Continents drift very slowly around the world, shifting their positions. During our lifetime, the shape of the Earth's landmasses cannot be seen to change. This is because continental drift occurs at about the same speed as the growth of our fingernails. However, geologists have proved that millions of years ago, the Earth looked very different. In fact, 250 million years ago all the separate continents that we see today were joined together as one giant landmass.
Over millions of years the changing configuration of landmasses and oceans affects the way that heat is stored in the atmosphere and in the oceans. This affects the Earth's climate. During the age of the dinosaurs 100 million years ago, the Earth was much warmer than it is today, with an average temperature perhaps as high as 25°C, and little or no snow and ice even at the poles. Since that time, the separation of the continents has changed the flow of ocean currents and of winds, and has isolated Antarctica at the South Pole, causing a slow cooling down of the Earth's climate to that of today, with large ice sheets covering Antarctica and Greenland. The size of these ice sheets has regularly grown and shrunk during the last few million years, but this is not due to continental drift but to changes in the Earth's orbit around the Sun.
| Pangea |
| Ocean gateways |
| Last 50 million years |
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