Tibetan Plateau

The Tibetan Plateau, also known as the Qinghai–Tibet Plateau, Qingzang Plateau, or as the Himalayan Plateau, is a huge flat area high above sea level. It sits where Central, South, and East Asia meet. It is the world's highest and biggest plateau. It covers 2,500,000 square kilometres (970,000 sq mi). The plateau is very high, with an average height of over 4,500 metres (14,800 ft). People call it "the Roof of the World".

The plateau has the starting points of many important rivers. These include the three longest rivers in Asia: the Yellow, Yangtze, and Mekong. It also has many glaciers. These glaciers and other features store fresh water, like a "water tower". Because of this, the Tibetan Plateau is sometimes called the Third Pole. It holds the most fresh water in the world outside the polar regions.

Tall mountain ranges surround the plateau. These mountains include the world's two highest peaks, Mount Everest and K2. The plateau covers parts of Tibet Autonomous Region, Qinghai, Sichuan, Gansu, Xinjiang in Western China. It also reaches into Bhutan, India, Pakistan, Nepal, Tajikistan and Kyrgyzstan. Scientists watch how climate change impacts this important area.

Description

The Tibetan Plateau is a huge, high area surrounded by tall mountains in Asia. To the south, it is bordered by the inner Himalayan range, and to the north by the Kunlun Mountains, which separate it from the Tarim Basin. The Salween, Mekong, and Yangtze rivers flow from its eastern and southeastern edges, passing through Yunnan, Sichuan, and Qinghai. In the west, the Karakoram mountains frame the plateau near Kashmir, and the Indus River begins in the western part of the plateau near Lake Manasarovar.

The plateau has a dry, grassy landscape with many mountains and large salty lakes. Rain and hail are rare, falling only 100 to 300 millimetres each year. The southern and eastern parts can support some grass for animals, but frost covers the ground for six months. Further north and west, the land becomes even higher, colder, and drier, reaching the remote Changtang region. Here, temperatures can fall below −40 °C in winter, making it one of the least populated places in the world.

Geology and geological history

Main article: Geology of the Himalayas

The Tibetan Plateau formed when the Indo-Australian Plate crashed into the Eurasian Plate about 70 million years ago. This made the Himalayas, one of Earth's youngest mountain ranges. It also closed the old Tethys Ocean and pushed up layers of rock.

Over millions of years, the land that is now the Tibetan Plateau rose slowly from a lower, valley-like shape. Today, it continues to rise by about 5 mm each year. Wind and rain wear it down a little, too. Scientists are not sure why the plateau has gentle slopes. Some think it was once a flat plain pushed up. Others believe wind and water smoothed its shape over time.

Environment

The Tibetan Plateau has many kinds of plants and animals, even though it is very high and doesn’t get much rain. You can find grasslands, areas that look like tundra, and even some forests and shrublands. Animals that live here include wolves, snow leopards, wild yaks, and many types of birds like cranes and vultures. One special spider lives here that can jump even at very high altitudes.

The World Wide Fund for Nature has identified many different areas, called ecoregions, across the Tibetan Plateau. These include places like the Pamir alpine desert, the North Tibetan Plateau–Kunlun Mountains alpine desert, and the Central Tibetan Plateau alpine steppe. Other areas include the Qaidam Basin semi-desert, the Qilian Mountains subalpine meadows, and the Yarlung Tsangpo arid steppe. The southeastern parts of the plateau have shrub and meadow areas that get more rain, and there are also conifer forests in some mountain valleys.

Human history

Main article: History of Tibet

Long ago, ancient humans called Denisovans lived on the Tibetan Plateau. Today, many people on the plateau are nomads, moving with their animals instead of farming. These traditions are important to Tibetan culture. One famous ancient civilization that grew here was the Tibetan Empire, which thrived from the 7th to the 9th century AD. The northern area, known as the Changtang, is too cold and high for many people to live there permanently.

Impact on other regions

Role in monsoons

Main article: Monsoon

Monsoons happen because land and oceans heat up and cool down at different speeds. Water takes longer to heat up and cool down than land. This means that during warm months, land heats up faster than the ocean. The warm air over land rises, creating a low-pressure area that pulls in moist air from the ocean. This moist air leads to more rain.

In winter, the land cools down quickly, but the ocean stays warm longer. This creates a high-pressure area over the land and a low-pressure area over the ocean, which can cause dry conditions over the land. Monsoons are big seasonal winds that affect weather patterns over large areas, and the Tibetan Plateau helps create the strongest monsoons on Earth.

The monsoons are helped by mountains and other natural features that lift the air, causing it to cool and form rain. This process is very important for the weather in many parts of Asia.

Glaciers

The ice on the Tibetan Plateau helps scientists learn about Earth’s past. In 2015, researchers studied ice from the Guliya glacier and found tiny bits of old viruses trapped inside.

The Tibetan Plateau holds a lot of the world’s ice, the third-largest store after polar regions. Because Earth’s temperature is rising, these glaciers are melting faster. This melting can cause floods and may affect water supplies for rivers such as the Indus and the Ganges. Scientists watch these changes to learn more about our planet.

See also: Effects of climate change and Retreat of glaciers since 1850