Flash floods have devastated Nepal. Climate change could make them routine

Powerful floods swept through mountain villages in Nepal and Tibet this week, killing more than 600 people and leaving nearly 2,000 others missing. Scientists believe a glacier — a massive, slow-moving sheet of ice — collapsed in the Himalayas and triggered the disaster. Experts are now warning that climate change is making dangerous events like this much more likely to happen in the future.

The floods destroyed roads, bridges, and homes in the mountain valleys below. Water levels at one monitoring station rose by as much as nine meters in just 30 minutes, giving people almost no time to escape. The speed of the flooding showed how little warning communities may have when a glacier breaks apart and releases a massive wall of water.

Scientists say that as the Earth gets warmer, glaciers in the Himalayas are melting faster and faster. David Simon, a professor at the University of London, said disasters like this flood are likely to keep happening as climate change makes summers hotter. He explained that key rivers of South Asia — including the Ganges, the Brahmaputra, and the Indus — have always depended on the slow, steady melting of mountain ice and snow.

As glaciers shrink, experts warn that up to 1.65 billion people could face serious water shortages in the future. Dr. Narelle van der Wel, a scientist at the World Meteorological Organization, explained that melting glaciers at first cause more flooding. But over time, as the ice disappears, there is less water stored in the mountains to feed rivers during dry seasons.

The problem is not only happening in Asia. In South America, glaciers in the Andes Mountains are also shrinking fast, and Peru has lost about 56 percent of its glacier ice over the last 60 years. Professor Bethan Davies of Newcastle University said rivers in that region are becoming drier and less reliable, making it very hard for local communities to get the water they need.

Professor Davies explained that melting ice also makes mountain slopes unstable and dangerous. When ice and frozen ground called permafrost melt, rocks and soil can break loose, leading to rockfalls, landslides, and avalanches. She said the Himalayan region is warming nearly twice as fast as the rest of the world, making the mountains more fragile and hazardous every year.

Professor Davies said communities in Nepal cannot be expected to simply adapt to floods this large on their own. She called for strong early warning systems so that people in danger have enough time to evacuate safely. She also pointed out that wealthier countries like the United Kingdom have produced far more greenhouse gas pollution than Nepal, yet Nepal is suffering the worst effects of climate change.

British Prime Minister Andy Burnham announced £5 million in aid for Nepal to help with the disaster. However, Nepal does not have enough monitoring equipment to detect floods before they strike. Officials admitted earlier this year that an early warning system in the Everest region had fallen apart, ten years after it was first installed.

Dr. van der Wel said that a good early warning system needs much more than just a weather forecast. It requires constant monitoring of glaciers, mountain lakes, and unstable slopes, fast sharing of data across borders, and clear plans to make sure warnings actually reach people in time. Scientists and experts agree that protecting vulnerable communities from climate change must become a priority for the world's wealthiest nations.