Picture the tundra. In all likelihood you're picturing a vast, frozen wasteland with snow everywhere and perhaps the occasional polar bear. There's actually more life in the tundra than you might realize, particularly during the summer when the long arctic days deliver a manic growing season. That he tundra is home to a variety of plants and animals is reason enough to call the tundra important, but this region of the world has other characteristics vital to life as we know it.
Perhaps the most famous feature of the tundra is its permafrost, referring to land that never thaws. While the surface layer of soil in the tundra does thaw during the summer, allowing plant and animal life to thrive, there is permanently frozen soil beneath this layer. This permafrost can vary in thickness from one to 1000 meters (that is, from roughly 3 to 3300 feet.) This frozen ground's proven vital to tracking climate change through the centuries, as any temperature change leaves its mark on the permafrost, and also alerted us to the rapid changes happening since the industrial revolution.
The rain-forest is often called the earth's lungs, because the extremely high plant density is responsible for converting a lot of the world's carbon dioxide into oxygen. A similar claim can be made about the tundra—it is the earth's carbon sink. Because a lot of otherwise fertile land is permafrost it contains a lot of carbon that would otherwise escape into the atmosphere. Scientists predict that if global temperatures continue to increase much of this carbon actually will be released, accelerating the increase in temperatures. Current climate models predict temperatures will rise to this point.
The tundra begins at the tree line. Imagine traveling north until you get to the point that there are no longer any trees at all—you've just passed the tree line. But just because there are no trees doesn't mean there are no plants at all; the tundra's long summer days mean a variety of plants that thrive during the summer. Typically tundras are teaming with grasses and wild flowers, and rocks are covered in lichen. Lichen is particularly common in the northern extreme of the tundra, where little else can grow. These plants all represent life thriving in one of the most extreme climates on earth.
The caribou and the reindeer, technically a single species, are spread across the entire tundra. Carbiou dwelling in North American and the reindeer on the Eurasian continent, though the creatures are different a few ways—caribou tend to be larger, for example. Also, reindeer are domesticated by northerners in the far north of Europe and Russia while the caribou is largely wild. Other creatures native to the tundra include doll sheep, brown and polar bears, and snow geese—all of which would lose their habitat were the tundra to disappear. Contrary to popular belief there are no penguins in the tundra; penguins live in Antarctica, the furthest place away from the tundra on the planet.
Unlike most ecosystems, development is not a threat to the tundra—scarcely anyone is itching to move to the frozen north. Oil and gas development, however, is widespread and without proper regulation can severely affect region's plants and animals. The biggest threat, however, is climate change, which could significantly alter the ecosystem in the tundra. This would not only harm the species native to the region but potentially the entire planet, as otherwise stored carbon is released into the atmosphere, speeding the process of climate change.