Why is it possible for tundra to occur in the Andes mountain range of South America and the Himalayas of central Asia?
Most of the tundra on Earth is found in the Arctic. However, tundra is also found in the Andes mountain range of South America and the Himalayas of central Asia. These regions are far from the Arctic Circle, so how is this possible. Please help!!
Good question! Most of the tundras of the world ARE in the artic circle, but as you noted, they do occur in the Andes Mountains and the Himalayas, which are both very high mountain ranges. The reason for this is because as you go up in altitude the temperature gets colder. Air pressure also decreases as altitude increases. (So not only do you get colder the farther you hike up the mountain, the air gets thinner too!) These two things are connected. As the air gets thinner, the molecules spread out, which cools them. Now we have a bunch of REALLY cold air on top of the mountain, now to deal with the little precipitation part.
When you have a mountain, sometimes you have what's called a "rain shadow effect." Basically, you have a wet area that a prevailing wind travels over and picks up moisture from. The prevailing wind, now loaded with moisture, blows across the land till it comes to the mountain, then blows upwards. As the altitude increases, the air gets colder. Cold air can hold much less moisture than warm air. So, the air cools and cools, until finally it can not hold the moisture any longer so it rains on one side of the mountain. Then the now- dry air continues it's way up and over the mountain. One side of the mountain gets rain, the other side is very dry. If the mountain range is very tall, as in the case of the Andes and Himalayas, it rains before the air gets to the top of the mountain. There is a figure on wikipedia I have included a link for that expains it better with a picture. Hope this helps!
The reason this is possible is because a biome does not get to be tundra based on its latitude. Instead, what makes tundra possible is temperature.
The most important basic defining features of tundra are 1) cold temperature and 2) little biodiversity. These two things are determined by temperature and not by latitude.
Most tundra is up in the Arctic because it's cold there. But high mountain regions also get to be very cold. If a mountain region can get to be just as cold as the Arctic, it can have tundra even if it's far from the Arctic Circle.
You are correct. They are not part of the tundra based on location, but based on elevation. Elevations in excess of 5,000 ft above sea level will affect temperature. That is why Flagstaff, AZ has a continental temperature pattern, while Phoenix, AZ bakes during the summer months.