By Tsering Dhundup
The surface area of numerous lakes on the Tibetan Plateau could increase by more than 50% by the end of the century due to global warming, while lakes around the world shrink, according to a new study titled “Widespread societal and ecological impacts from projected Tibetan Plateau lake expansion”.
The research team from China, Wales, Saudi Arabia, the United States and France said that this would correspond to a fourfold increase in water storage compared to what the area experienced over the last 50 years. The water volume of these lakes in Tibet is estimated to expand by over 600 billion tonnes due to increased rainfall from climate warming and glacier melt.
The researchers noted the potential negative economic impact on Tibet, running into billions. “It is one of the regions that is most vulnerable to climate change, acting as an early warning signal for the wider effects of global warming,” the researchers wrote.
While large lakes in other regions of the world have been losing water storage due to rising temperatures and human activity, lakes in the Tibetan plateau have been expanding in recent decades due to warmer and wetter conditions. This expansion is mainly driven by increases in net precipitation, with melting glaciers contributing but having limited storage.
The study published in the peer-reviewed journal Nature Geoscience last month involved a simulation model for 2021 to 2100, incorporating climate drivers with field surveys and remote sensing, under different socioeconomic scenarios to examine future impacts. The northern part of the plateau is expected to see a twofold increase in total lake area, the largest increase across the region. Lakes in the southeast, northwest, and central parts will also expand significantly. Even the southern part, which had a shrinking trend, began expanding in 2021.
The study revealed that the Siling Lake (Tibetan: Siling Tso), the largest lake in the so-called Tibet Autonomous Region (traditional Tibetan province of U-Tsang), could see a water volume increase of around 66 billion tonnes, with about an 800 sq. km increase in area. Despite the northern parts experiencing the largest increase in water storage, roads in the northeast, with more human activity and infrastructure, will be most vulnerable to floods. Under the socioeconomic scenario, inundated roads could lead to economic losses of 20 billion to 50 billion yuan (US$2.7 billion to US$6.9 billion) by the century’s end. This “is a serious threat that should be considered in future rail and road planning,” the team said.
The study further predicted that by the end of the century, 615 human settlements and over 500,000 livestock could be disturbed due to water inundation, severely affecting local pastoralist’s livelihoods and exacerbating poverty levels. The researchers cited an incident in 2011 where a lake burst in the Hoh Xil Nature Reserve in the traditional Tibetan province of Amdo which is now known as Qinghai Province, blocking the migration route for Tibetan antelopes.
“Loss of cropland could disrupt food production, affecting both local food security and the regional agricultural economy,” the paper said. Several lakes are expected to merge as they expand, threatening infrastructure and ecology. The team also expressed concern about increased greenhouse gas emissions from the expanding lakes, creating a feedback loop of further warming and lake expansion.
“The expanding lakes pose challenges to existing and planned infrastructure and communities and require urgent implementation of effective adaptation and sustainable management strategies to mitigate socioeconomic repercussions,” the team said. “Our study serves as a scientific guide for future planning and provides valuable insights to avoid the devastating consequences of the impending lake expansion.”
Dhondup Wangmo, research fellow at the Environment and Development Desk of the Tibet Policy Institute, shared her insights on the issue, stating, “Although scientific studies have suggested multiple factors to account for lake expansion, a consensus on the primary driver remains elusive. Scientific research has identified three common factors: the melting of glaciers, degradation of permafrost, and alterations in precipitation patterns. Whatever the factors are, this expansion vividly demonstrates how climate change manifests in Tibet. The increasing size of these lakes will jeopardize the water system, impact local pastoralists, and heighten the risk of water-related disasters such as glacier lake outbursts.”
