Tibetan Plateau

The Tibetan Plateau, also known as the Qinghai–Tibet Plateau, Qingzang Plateau, or as the Himalayan Plateau, is a vast elevated plateau located at the intersection of Central, South, and East Asia. It is the world's highest and largest plateau above sea level, with an area of 2,500,000 square kilometres (970,000 sq mi). With an average elevation exceeding 4,500 metres (14,800 ft), it is often called "the Roof of the World".

The plateau contains the headwaters of many important rivers, including the three longest rivers in Asia: the Yellow, Yangtze, and Mekong. Its many glaciers and other features act like a "water tower", storing fresh water and helping rivers flow. Because of this, the Tibetan Plateau is sometimes called the Third Pole, as it holds the largest reserve of fresh water outside the polar regions.

The Tibetan Plateau is surrounded by tall mountain ranges that include the world's two highest peaks, Mount Everest and K2. It covers parts of Tibet Autonomous Region, Qinghai, Sichuan, Gansu, Xinjiang in Western China, as well as areas in Bhutan, India, Pakistan, Nepal, Tajikistan and Kyrgyzstan. Scientists study how climate change affects this important region.

Description

The Tibetan Plateau is a vast, high area surrounded by tall mountain ranges 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 features 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's history is linked to the formation of the Himalayas. These mountains are among the youngest on Earth, created when the Indo-Australian Plate crashed into the Eurasian Plate about 70 million years ago. This crash closed the old Tethys Ocean and pushed up layers of rock to form towering mountains.

Over millions of years, the land that is now the Tibetan Plateau rose slowly. It started lower and more valley-like but gradually lifted higher. Today, the plateau continues to rise by about 5 mm each year, though wind and rain wear it down a little too. Scientists debate why the plateau has such gentle slopes, with some thinking it was once a flat plain pushed up, and others believing wind and water smoothed out its shape over time.

Environment

The Tibetan Plateau is home to many different 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 from around 200,000 to 40,000 years ago. Today, many people on the plateau are nomads, moving with their animals instead of farming. These nomadic traditions are important to Tibetan culture, especially in the western, southern, and eastern parts of the plateau. 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 because it can hold more heat. 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 like big seasonal winds that affect weather patterns over large areas, and the Tibetan Plateau plays a major role in creating 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. These viruses had infected plants or tiny organisms many thousands of years ago.

The Tibetan Plateau holds a huge amount of the world’s ice, the third-largest store after polar regions. Because Earth’s temperature is rising, these glaciers are melting faster than anywhere else. This melting can cause floods and may one day affect water supplies for rivers such as the Indus and the Ganges. Scientists watch these changes closely to understand how our planet is shifting.

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