Shrubs and grasses are springing up around Mount Everest and across the Himalayas, one of the most rapidly heating regions of the planet. The impact on water supplies of the small but significant increase in vegetation between the treeline and snowline is not yet known but could increase flooding in the vast Hindu Kush Himalayan region, which covers 4.2msq km(1.6m sq miles), feeds Asia’s 10 largest river systems and supplies 1.4 billion people with water.
Scientists used satellite data to identify increases in vegetation in the inaccessible subnival (the highest zone allowing plant growth) ecosystem, made up of grasses and dwarf shrubs with seasonal snow. This ecosystem is known but could play a crucial role in the region’s hydrology, covering between five and 15 times the area of permanent glaciers and snow in the region.
The melting of Himalayan glaciers has doubled since the turn of the century, with more than a quarter of all ice lost over the last four decades. That would be bad news for the Himalayas. The subnival zone is where seasonal snow is held and if it is warmer you will get flashy hydrology – quicker melt rates and an increased risk of flooding.
