(TibetanReview.net, Nov12’22) – It is not just the quantity of water flowing from the Tibetan Plateau but also, perhaps more seriously, the quality of water which is being ominously affected as a result of global warming. Chinese scientists believe that global warming is slowly turning one of the world’s most important sources of fresh water into toxic mud, and they do not yet know how bad the problem is, reported the scmp.com Nov 11.
The report noted that the source, the Tibetan Plateau and its surrounding mountain regions, known in environmental circles as the “Asian water tower”, is the source of Asia’s 10 major rivers, delivering water to almost 2 billion people – about a quarter of the world’s population.
The Chinese researchers were reported to have called for urgent action to improve the water quality in both the upstream and downstream areas of the region, which they believe will rapidly deteriorate as global temperatures rise.
Publishing their research in the journal Nature Reviews Earth & Environment on Oct 11, researchers from the Chinese Academy of Sciences have said climate change would accelerate glacier melt, increasing upstream flows of sediments and other contaminants that will compromise water quality downstream.
They have suggested better monitoring of the problem by creating a research network based on water quality data, as well as joint actions by upstream and downstream countries to mitigate the issue.
The report noted that the Asian water tower, which is home to most glaciers outside the Arctic and Antarctica, is highly sensitive to climate change.
While most studies of the region so far have focused on water quantity, water quality assessments are becoming increasingly important for local and downstream livelihoods, the researchers have said.
Their study was cited as saying that global warming has caused glacier melt and permafrost thawing in the region. As a result, sediment fluxes (the flows caused by melting) in the headwaters have increased during the past six decades.
An earlier study, published in Science in Oct 2021, was cited as saying the total sediment flux in the Asian water tower is projected to more than double by 2050 under an extreme climate change scenario.
The authors were stated to have noted that along with changes in water volume, upstream water brings chemicals, including arsenic, calcium and magnesium, to downstream rivers.
As a result, downstream water quality will not only be increasingly impacted by human activities and climate change, but also by the changes in upstream water quality.
“There are relatively few monitoring sites in the Tibetan Plateau region and most of them are observing the hydrology. We don’t have systemic and long-term monitoring on the water quality,” a researcher, who requested anonymity because he was not authorized to talk to the media, was quoted as saying.
The study was stated to have concluded: “We advocate for the creation of a research network that collects and stores basin-scale, cross-border, standardized data of surface and groundwater quality, glacier run-off geochemistry, permafrost degradation, and pollutant release.”