A mountain is a landform that extends above the surrounding terrain in a limited area. A mountain is generally steeper than a hill, but there is no universally accepted standard definition for the height of a mountain or a hill although a mountain usually has an identifiable summit. Mountains cover 54% of Asia, 36% of North America, 25% of Europe, 22% of South America, 17% of Australia, and 3% of Africa. As a whole, 24% of the Earth's land mass is mountainous. 10% of people live in mountainous regions. Most of the world's rivers are fed from mountain sources, and more than half of humanity depends on mountains for water.
The adjective montane is used to describe mountainous areas and things associated with them.
The height of a mountain is measured as the elevation of its summit above mean sea level. The Himalayas average 5 km above sea level, while the Andes average 4 km. The highest mountain on land is Everest, 8,848 metres (29,030 ft) in the Himalayas.
Other definitions of height are possible. The peak that is farthest from the center of the Earth is Chimborazo in Ecuador. At 6,267 meters (20,560 ft) above sea level it is not even the tallest peak in the Andes, but because Chimborazo is very close to the equator and the Earth bulges at the equator, it is 2,150 meters (7,100 ft) further away from the Earth's center than Everest. The peak that rises farthest from its base is Mauna Kea on Hawaii, whose peak is 10,200 metres (33,500 ft) above its base on the floor of the Pacific Ocean.
Even though Everest is the highest mountain on Earth today, there have been much taller mountains in the past. During the Precambrian era, the Canadian Shield once had mountains 12,000 metres (40,000 ft) in height that are now eroded down into rolling hills. These formed by the collision of tectonic plates much like the Himalaya and the Rocky Mountains.
At 26 kilometres (85,000 ft) (Fraknoi et al., 2004), the tallest known mountain in the solar system is Olympus Mons, located on Mars and is an ancient volcano. Volcanoes have been known to erupt on other planets and moons in our solar system in our life-times (volcanoes on Venus for example, constantly erupt) and some of them erupt ice instead of lava. Several years ago, the Hale telescope recorded the first known live images of a volcano erupting on a moon in our solar system.
High mountains, and mountains located closer to the Earth's poles, have elevations that exist in colder layers of the atmosphere. They are consequently often subject to glaciation and erosion through frost action. Such processes produce the popularly recognizable mountain peak shape. Some of these mountains have glacial lakes, created by melting glaciers; for example, there are an estimated 3,000 glacial lakes in Bhutan.
Why climb the mountain? Because it's there! Many mountainous regions hold a certain fascination for numerous people on vacation from around the world. But every year, thrill seekers are hurt and sometimes killed from accidents that have happened whìle traversing these mountains. Most of the time, ìf precautions are taken, you can keep you and your family safe.
If you are goìng to be traveling ìn the mountains, there are a few things to consider before you head out, to ensure you are safe should a problem arise. First, dress ìn layers. One of the main difficulties when traveling through higher altitudes ìs the huge variance ìn temperature that you wìll face. Should you be stranded ìn the mountains at night, ìt can become very cold. To avoid problems that come as a result of the weather, dress warmly but ìn layers that can be removed ìf ìt becomes too warm.
Before leaving, make sure that someone knows where you are heading, and when you expect to be back. This ìs crucial to your rescue ìf you should become lost. If there ìs someone expecting you to be back at a certain day and time and you do not return, a search party can begin. However, ìf no one knows where you are and when to expect you, then ìt may be weeks before they start looking.
Always travel wìth a hunting knife or pocketknife. If you are heading out on an unmarked trail, mark your path every few feet by gouging out a notch on a tree or rock. This way, ìf you should become lost, you wìll be able to retrace your steps to get back to your starting place.
Always travel wìth a flashlight and extra batteries. Also, make sure you take waterproof matches along wìth you. A space blanket and a small tarp are essential to your survival ìn the mountain wilderness. Bring along some water purification tablets ìn case you should need to search for something to drink. A container that can hold water ìs also a must.
If you do find that you are lost ìn the mountains and do not know how to return to where you came from, the best thìng to do ìs to stay where you are. If you move around, you wìll be harder to find when rescue comes. However, ìf you are near a stream and you feel you must keep moving, head downstream. This wìll take you towards the bottom of the mountain, whìch ìs usually closer to a road or town. If you can find shelter where you are, stay put and get out of the elements. Leave a marker, lìke a brightly colored jacket or tarp, so that rescuers mìght find you. Then you need to get ìnto shelter.
Stay away from any animals you mìght encounter. The animal you wìll be most likely to encounter ìs a bear. Whatever you do, do not surprise an unsuspecting bear! Catching a bear off guard ìs the reason for most bear attacks.
Do not become overly concerned about food. Watch the local wildlife and find berries or nuts that you can eat. Remember that the human body can survive up to three weeks wìth no food, but ìt is much more important to stay hydrated, as lacking water can bring you close to death quickly. Make sure you have access to water at all times.
K2, 8,611 meters (28,250 ft)
Sufficiently tall mountains have very different climatic conditions at the top than at the base, and will thus have different life zones at different altitudes. The flora and fauna found in these zones tend to become isolated since the conditions above and below a particular zone will be inhospitable to those organisms. These isolated ecological systems are known as sky islands and/or microclimates. Tree forests are forests on mountain sides which attract moisture from the trees, creating a unique ecosystem. Very tall mountains may be covered in ice or snow.
Mountains are colder than lower ground, because the Sun heats Earth from the ground up. The Sun's radiation travels though the atmosphere to the ground, where Earth absorbs the heat. Air closest to the Earth's surface is, in general, warmest (see lapse rate for details). Air as high as a mountain is poorly warmed and, therefore, cold. Air temperature normally drops 1 to 2 degrees Celsius (1.8 to 3.6 degrees Fahrenheit) for each 300 meters (1000 feet) of altitude.
Mountains are generally less preferable for human habitation than lowlands; the weather is often harsher, and there is little level ground suitable for agriculture. At very high altitudes, there is less oxygen in the air and less protection against solar radiation (UV). Acute mountain sickness (caused by hypoxia - a lack of oxygen in the blood) affects over half of lowlanders who spend more than a few hours above 3,500 meters (11,483 feet).
A number of mountains and mountain ranges of the world have been left in their natural state, and are today primarily used for recreation, while others are used for logging, mining, grazing, or see little use of any sort at all. Some mountains offer spectacular views from their summits, while others are densely wooded. Summit accessibility ranges from mountain to mountain; height, steepness, latitude, terrain, weather, and the presence or lack thereof of roads, lifts, or tramways are all factors that affect accessibility. Hiking, backpacking, mountaineering, rock climbing, ice climbing, downhill skiing, and snowboarding are recreational activities typically enjoyed on mountains. Mountains that support heavy recreational use (especially downhill skiing) are often the locations of mountain resorts.
Wildlife and Plants
Mount Olympus in Greece.
If you climb from base to peak of a big mountain, you will pass through a number of different types of plant community. The vegetation on the lower slopes largely depends on which climate zone the mountain is in. The foothills may be covered in broadleaved forests. On the upper slopes, needleleaf trees (coniferous trees) like spruce and pines. As you climb higher it gets colder and colder and the trees eventually thin out and disappear.
Climate and Mountains
The main differences in climate of mountains are temperature and moisture. Mountains tend to have much wetter climates than the surrounding flat land. They receive more rainfall than low lying areas because the temperature on top of mountains is lower than the temperature at sea level. That is why you often see snow on the top of mountains all year round. The higher the place is above sea level the colder it will be.
Climates change rapidly on mountains, becoming colder the higher the altitude gets. This happens because as altitude increases, air becomes thinner and is less able to absorb and retain heat. The cooler the temperature the less evaporation there is meaning that there is more moisture in the air.
Because of the rapid changes in altitude and temperature along a mountain slope, multiple ecological zones are “stacked” upon one another sometimes ranging from dense tropical jungles to glacial ice within a few kilometres.
The climate on mountains change the higher up you go. Generally the climate get progressively colder with increased altitude. Some mountains reach higher than the clouds. At this altitude the extreme cold and high winds cause blizzards.
The highest parts of the mountain support only sparse grasses and low-growing Alpine flowers which can withstand the harsh conditions. If the mountain is high enough even this vegetation disappears and the peak is bare and rocky and perhaps covered in snow and ice.
High mountains are a bleak habitat for animal life. Food is scarce and the climate is very cold. Mammals living here have adapted to survive the bitter cold and most have thick woolly fur. Mountain sheep and goats like the chamois and ibex are very sure-footed to help them climb the jagged, craggy slopes.
If you climb from base to peak of a big mountain, you will pass through a number of different types of plant community. The foothills may be covered in broadleaved forests; higher up, coniferous trees like spruce and pines appear.
As you climb higher it gets colder and colder and the trees eventually thin out and disappear. The highest parts of the mountain support only sparse grasses and low-growing Alpine flowers. If the mountain is high enough even this vegetation disappears and the peak is bare and rocky and perhaps covered in snow and ice.
Above the tree-line in the mountains of Africa, strange-looking giant groundsels and giant heathers grow.
A carpet of flowers
Alpine plants in high mountain regions are slow growers. The brief summers are spent building up food stores in their roots in order to survive the biting cold of winter. In spring, Alpine plants burst briefly into flower, and the Alpine meadow is a riot of color.
Whilst foothills of mountains may have a tropical climate, the peaks may be covered in ice. The uppermost level of mountains is often bare rock and snow. Tibet and the Himalayas and other mountain ranges such as the Rocky Mountains or the Andes are good examples of this. In Africa, only the isolated peaks of Mount Kenya and Kilimanjaro and the Ruwenzori range are high enough to carry permanent snow.
The weather can change very quickly up mountains. For example, in just a few minutes a thunder storm can roll in when the sky was perfectly clear, and in just a few hours the temperatures can drop from extremely hot temperatures to temperatures that are below freezing.
Mountains can affect the climate of nearby lands. In some areas, mountains block rain, so that one side of a mountain range may be rainy and the other side may be a desert.
Mountains make up about one-fifth of the world's landscape,
and provide homes to at
least one-tenth of the world's people.
The world's highest peak on land is Mount Everest in the Himalayas. It is 8,850.1728 m ( 29,036 ft ) tall.
The world's highest mountain, from its base on the ocean floor, is Mauna Kea, on Hawaii. It is 10,203 m ( 33,474 ft ) high but only 4,205 m ( 13,796 ft ) is above sea level.
Ben Nevis is also the highest mountain in Great Britain.
The tallest known mountain in the solar system is Olympus Mons, located on Mars.
There are mountains under the surface of the sea!
Mountains occur more often in oceans than on land; some islands are the peaks of mountains coming out of the water.
About 80 per cent of our planet's fresh water originates in the mountains.
All mountain ecosystems have one major characteristic in common - rapid changes in altitude, climate, soil, and vegetation over very short distances.
Plants that may be found on mountains include conifers, oak, chestnut, maple, junipers, stonecrops, campions, mosses, ferns and climbers.
The highest 14 mountains in the world are all found in the Himalayas
In some mountainous areas the rivers are permanently frozen. These are called glaciers.
The Alps are the most densely populated mountain area in the world.