Tibet’s Climate Crisis: Unstoppable Lake Expansion

 

Climate change is a global issues that affects the entire planet. However its impact is particularly severe on the Tibetan Plateau. The Tibetan Plateau, often known as the world’s third pole, has been undergoing significant environmental changes due to climate change. One of the most striking manifestations of these changes is the expansion of lakes across the plateau. This phenomenon is reshaping the region’s hydrology, ecology, and human livelihoods, with far-reaching implications for Asia’s water resources.

The Tibetan Plateau, covering approximately 2.5 million square kilometers, is the source of many of Asia’s major rivers, including the Drichu (Yangtze), Machu (Yellow), Zachu (Mekong), Gyalmo Ngulchu (Salween), Senge Khabab (Indus), and Yarlung Tsangpo (Brahmaputra). Unlike other region, the plateau is warming up by 0.3 °C per decades, more than twice the global average. This rapid warming has led to increased glacial melt and permafrost thawing, contributing significantly to the expansion of lakes.

Over the last few years, many research and survey have documented a dramatic increase in the size and number of lakes due to climate change on the plateau. According to a research team led by the Institute of Atmospheric Physic (IAP) under the Chinese Academy of Sciences, there are around 1,400 lakes larger than one square kilometer on the plateau. With climate warming and wetting, the lakes there have experienced a dramatic expansion, which poses a flood risk to surrounding villages and roads. Satellite imagery reveals that the total lake area has expanded by over 30% in recent decades.

Another paper recently published in Nature Geoscience suggest that by 2100, the surface area of endorheic lakes (a closed basin) on the Tibetan plateau will increase by over 50% and water level rise by around 10m relative to 2020 due to increase in precipitation and glacier melt water. Notably, 12 lakes including Nam tso, Serling Tso, Tso Ngonpo (Qinghai Lake)  were identified as potentially more vulnerable to climate change. Without hazard mitigation measures, the expanding lake is expected to inundate crucial human infrastructure. This includes over 1,000 km of roads, approximately 500 settlements, and about 10,000 km² of ecological components such as grasslands, wetlands, and croplands.

 

Driver of lake expansion

These expansion is primarily driven by three factors: first, the glacial melt, Tibet with its vast amounts of glaciers are melting rapidly due increase in the mean surface temperature. The accelerated melting of glaciers feeds directly into the lakes, increasing their water volume. Most of the alpine lakes, which are dominantly fed by glaciers have expanded rapidly over the last 40 years. From 1970 to 2010, the total lake area on the Plateau increased by 34% with most of this expansion occurring on the central-northern Plateau and at a faster rate after 2000. With the expansion of these lakes, there will be more frequent mountain hazards, such as glacial lake outburst flood, landslides and mudslides.

Secondly, Permafrost Thaw, Thawing permafrost releases previously trapped water, further contributing to lake expansion. Over the last 50 years, Serling tso, in particular located within permafrost regions surrounded by glaciers, has exhibited the greatest increase in water storage.

Finally, Increased Precipitation, Climate change has altered precipitation patterns, with many parts of the plateau receiving more rainfall and snow. Some studies suggest that the increasing precipitation and decreasing evaporation have led to the expansion of lake in tibet. Since the mid-1990s, the plateau has been receiving more precipitation. A recent study involving the examination of impacts from projected Tibetan plateau lake expansion also showed that an increase in precipitation has sustain lake growth.

Impact of Climate change

Due to the impact of climate change, the Tibetan plateau which was once a dry and cold has changed into warm and wet. For the people living on the Tibetan Plateau, the increasing temperature and more precipitation has led to the overall improvement in the ecosystem with more vegetation coverage. However, the rise of the temperature has affected the stability of glaciers and permafrost in the region.  The melting of glaciers and permafrost led to the expansion of lakes which further led to increase in the frequency of geological disasters which pose a threat to infrastructure, such as roads and settlements, which are often situated close to existing water bodies. The displacement of communities and the loss of arable land due to lake expansion are growing concerns. The expansion of lakes also has profound ecological consequences. The changing hydrological landscape affects local biodiversity, particularly aquatic and bird species that rely on these habitats. For instance, the melting of glaciers and increasing influx of freshwater into the lake showed a widespread declines in water salinity, which has substantially impact the physical environment of lakes, altering the species richness, composition and the trophic structure of lake ecosystems.

The impact of the climate change is not restricted to the Tibetan plateau only but it has its consequences far beyond the border. Since the Tibetan Plateau acting as the Water Tower of Asia plays a crucial role in regional water security. The changes in its hydrology have downstream effects on the major rivers that support millions of people in South and East Asia. According to Yang Yong, director of the Hengduan Mountain Research Institute, over the past 12 years, the Chemayungdung glaciers (Jiemayangzong), the source of the Yarlung Tsangpo, have receded by 400 meters, with the melt water flowing into a glacial lake. The increased rates of snow and glacial melt are likely to increase summer flows for a few decades and accelerate glacial lake expansion. This variations in the river flow can impact agriculture, hydroelectric power generation, and freshwater water supplies in downstream countries like India and Bangladesh.

Conclusion

Lake expansion on the Tibetan Plateau serves as a stark reminder of the profound impacts of climate change on the world’s highest and the largest plateau. The future of lake expansion on the Tibetan Plateau depend on the trajectory of climate change. If current warming trends continue, it is likely that lakes will keep expanding, further altering the region’s hydrological, ecological dynamics as well as on the local pastoralists whose livelihood and communities are affected by the inundation of vast areas of grazing land.

It underscores the need to recognize the global ecological importance of the Tibetan plateau and make Tibet central to any discussion on global climate change, and need for comprehensive global climate action to protect these fragile environments and the source of water for millions of people who depend it. As the Roof of the World continues to transform, understanding and responding to these changes is more critical than ever for ensuring regional and global water security. It is also important consider the role of local ecological knowledge in climate change mitigation and adaptation strategy.