By the end of the century, the surface area of some lakes in the Qinghai-Tibet Plateau could increase by more than 50 per cent – while other lakes around the world shrink – a new study has found.
Endorheic lakes, also known as closed lakes, do not have an outlet to drain into.
While melting glaciers also contribute to this phenomenon, the researchers said the glaciers that remain have “limited storage”.
In the northern part of the Qinghai-Tibet Plateau , a twofold increase in total lake area is expected – the largest increase across the plateau.
Plus, as the lakes’ area expands, the team said there is a “growing concern about increased emissions of greenhouse gases , including carbon dioxide and methane, into the atmosphere”.
If these predictions are correct, the researchers said it could have a massive economic impact on China, running into the billions.
The water volume of the lakes in the plateau in southwest China is estimated to expand by more than 600 billion tonnes, largely due to increased rainfall caused by climate warming , as well as the melting of glaciers.
By the end of the century, the surface area of some lakes in the Qinghai-Tibet Plateau could increase by more than 50 per cent – while other lakes around the world shrink – a new study has found.
“Our results suggest that by 2100, even under a low-emissions scenario, the surface area of endorheic lakes on the Tibetan Plateau will increase by over 50 per cent (around 20,000 sq km [7,722 square miles]) and water levels will rise by around 10 metres [32 feet] relative to 2020,” the scientists wrote in a paper published in the peer-reviewed journal Nature Geoscience on May 27. Endorheic lakes, also known as closed lakes, do not have an outlet to drain into.
The 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.
If steps are not taken to mitigate this, “more than 1,000 km of roads, approximately 500 settlements and around 10,000 sq km of ecological components such as grasslands, wetlands and croplands,” will become submerged, the team said.
The Qinghai-Tibet Plateau, known as the “ Water Tower of Asia ”, is the highest and largest plateau in the world and is home to more than 1,000 lakes with large reserves of water in both liquid and ice form.
“[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 parts of the world have been experiencing a decline in water storage due to both rising temperatures and human activity, lakes in the plateau have actually been expanding in recent decades due to warmer and wetter conditions.
This has mostly been driven by increases in net precipitation. While melting glaciers also contribute to this phenomenon, the researchers said the glaciers that remain have “limited storage”.
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As part of the study, the team developed a simulation model for the period of 2021 to 2100 incorporating climate drivers with field surveys and remote sensing, all set to different socioeconomic scenarios to examine the future impact of increasing water storage in the plateau.
In the northern part of the Qinghai-Tibet Plateau , a twofold increase in total lake area is expected – the largest increase across the plateau. Lakes in the southeast, northwest and central parts of the plateau will also see significant expansion.
In fact, even though the southern part of the plateau used to see a shrinking trend in lake changes, it also began expanding in 2021, the team found.
The largest lake in the Tibet autonomous region, Selin Co (Siling Lake), could see an increase in water volume of around 66 billion tonnes – about an 800 sq km increase in lake area.
Despite the northern parts of the plateau being projected to experience the largest increase in water storage, roads in the northeast – where there is more human activity and infrastructure – will be the most vulnerable to inundation.
Looking at the researchers’ middle socioeconomic scenario, they estimated that inundated roads could directly lead to an economic loss of 20 billion yuan to 50 billion yuan (US$2.7 billion to US$6.9 billion) by the end of the century.
This “is a serious threat that should be considered in future rail and road planning,” the team said.
Many villages and livestock pens are located next to lakes in the plateau, and by the end of the century, 615 human settlements could be inundated by water.
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More than 500,000 livestock could also be disturbed, and the inundation of grassland could lead to less livestock production “severely affecting the livelihoods of local pastoralists and further exacerbating poverty levels,” the researchers wrote.
The team pointed to an incident in 2011 where a lake in the plateau’s Hoh Xil Nature Reserve “burst”, leading to a blockage of the migration route for Tibetan antelope
“Loss of cropland could disrupt food production, affecting both local food security and the regional agricultural economy,” the paper said.
The team found that several lakes are also expected to merge together as their area expands, which could also threaten infrastructure and ecology.
Plus, as the lakes’ area expands, the team said there is a “growing concern about increased emissions of greenhouse gases , including carbon dioxide and methane, into the atmosphere”.
This could create a feedback loop, as increased emissions would cause more warming, which would in turn cause further lake expansion in the plateau.
“The expanding lakes pose challenges to existing and planned infrastructure and communities and requires 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.”
