Mountains of the World: Formation and Importance

Mountains cover about a quarter of the Earth's land surface and are home to about a tenth of its people, while providing water, timber, minerals and recreation to many more. The highest ranges are young fold mountains, formed by plate collision: the Himalayas in Asia, the Andes in South America, the Rockies in North America, the Alps in Europe and the Atlas in North Africa. Older, worn-down ranges, such as the Appalachians in North America and the Urals between Europe and Asia, are lower and rounder, having been eroded over hundreds of millions of years. Block mountains form where faulting lifts a block of crust, as in the Vosges in Europe, and volcanic mountains, such as Mount Fuji in Japan and Mount Kilimanjaro in Tanzania, are built by eruptions.

The Andes, running along South America's west coast, are the world's longest mountain range on land, at about 7,000 kilometres, and the site of the world's highest peaks outside Asia, including Aconcagua in Argentina, at about 6,961 metres, the highest peak outside Asia. The Himalayas contain all fourteen of the world's peaks above 8,000 metres, including Everest at 8,848.86 metres. The Rockies and the Alps are younger than the Appalachians but older than the Himalayas in geological terms, and each range has its own pattern of valleys, passes and glaciers shaped by ice, water and tectonic forces.

Mountains matter far beyond their scenery. They are water towers: snow and glaciers store water and release it in the dry season, feeding rivers that support billions of people downstream, from the Indus and Ganga to the Rhine and the Colorado. They create their own climates, forcing moist air to rise and rain on the windward side while leaving a rain shadow on the leeward side. They shelter distinctive plants, animals and cultures, and they provide minerals, hydropower, tourism and strategic depth. At the same time, mountain communities often face isolation, poor infrastructure, landslides and limited access to services.

For civil studies, mountains connect geology, climate, water and development. A road, dam or mine in the mountains has larger downstream effects than a similar project on a plain, because it can alter water, trigger landslides or cut through fragile ecosystems. Mountain policy therefore needs special rules: building codes for earthquakes and landslides, protection for watersheds, and investment in connectivity, health and education that recognises distance and altitude rather than treating mountain districts as ordinary districts with fewer people.