Increased flooding is predicted to occur in the Himalaya and Pamir regions of the world, known as the Third Pole, due to climate change. A study predicting the increased risk of flooding in the region dominated by high-altitude glaciers is published in the journal Nature Climate Change.
The risk of flooding comes largely from melting glaciers and the resulting lakes forming in the region. Researchers from the University of Geneva (UNIGE), Switzerland have demonstrated how these newly-formed lakes will transform the communities living within the Third Pole region into flood hotspots.
Using satellite imagery and topographic modeling, a team of Swiss and Chinese climatologists determined the risk resulting from 7,000 glacial lakes that are already present in the Third Pole. Many of these existing glacier lakes have already caused flooding, a fact that allowed the research team to extrapolate future flood risk.
Co-author Simon Allen, a researcher at the Institute of Environmental Sciences of the UNIGE, comments: "We compared our results with a catalogue of past glacial lake floods, which allowed us to validate our approaches. Once we confirmed that the approaches accurately identified current dangerous lakes, we could then apply these methods to future scenarios." With this method, Allen and his colleagues showed that one in six (1,203) of existing glacial lakes posed a high to very high risk to downstream communities, particularly in the eastern and central Himalayan regions of China, India, Nepal, and Bhutan.
"These regions have experienced glacial lake outburst floods before, but these events have tended to be repetitive and linked to advancing glaciers. Authorities and communities will be less familiar with the types of spontaneous events we consider here in a deglaciating landscape, so this calls for awareness-raising and education on the new challenges that will emerge," says Markus Stoffel, who is a Professor at the Institute for Environmental Sciences of the UNIGE.
According to their calculations, the flood risk could almost triple in the coming years. "The speed at which some of these new hazardous situations are developing surprised us," says Stoffel. "We are talking a few decades not centuries -- these are timeframes that demand the attention of authorities and decision-makers." These findings point toward the urgent need for long-term collaborative approaches that transcend political borders.