Drought due to reduced snowmelt (WFP, UNEP & NEPA - 2016)

Whereas drought in rainfed areas is primarily caused by lack of rainfall locally, drought in irrigated areas is in large part linked to climate conditions further upstream. Spring and summer water flows in all three of Afghanistan's main irrigation systems - rivers, karez and springs - depend to a large extent on the amount of snow that falls the preceding winter in the Hindu Kush mountains or the Central Highlands, where these systems originate. Lower snowfall in winter leads to lower snowmelt in the spring and summer, leading to reduced water flows in downstream irrigation systems. For example, an area which relies on karez irrigation could face drought in the summer—despite normal local rainfall conditions that year—due to lack of snow during the preceding winter at the catchment source in the mountains. To understand where drought risk has increased most in irrigated areas over the past few decades, we therefore looked at changes in winter snowfall in the mountains where the country’s five major river basins originate. For livelihood zones located in the Northern, Harirod-Murghab and Helmand basins, we looked at changes in snowfall in the Central Highlands. For the Kabul basin, we looked at changes in snow-fall in the Hindu Kush mountains, further north east. Finally, for the Amu Darya basin, which is part of a larger transboundary catchment originating outside of Afghanistan, we looked at changes in snowfall in the Pamir mountains, in the Wakhan corridor and in neighboring Tajikistan. Over the past thirty years, the risk of drought caused by reduced snow/ ice melt appears to have increased the most in north-east Afghanistan, due to reduced winter snowfall in the upper parts of the Hindu Kush/ Pamir mountains (in Tajikistan and Badakhshan).

Note that this map shows the drought risk related to changes in annual snowmelt in elevated areas, which have an immediate impact on river flows downstream. However, it does not capture the longer term drought risk associated with the gradual disappearance of permanent glaciers which also feed into rivers downstream.

Source: The map comes from a report "Climate Change in Afghanistan: What does it Mean for Rural Livelihoods and Food Security?", which was produced jointly by the World Food Programme (WFP), the United Nations Environment Programme (UNEP) and Afghanistan's National Environmental Protection Agency (NEPA). The map was produced based on the livelihood zones produced by FEWSNET.