A hand-drawn whiteboard animation showing the socio-environmental challenges of water insecurity in Peru’s glacier-fed Rio Santa catchment. A research project by SIGMA Peru research team. Principal Investigators: Dr Caroline Clason, University of Plymouth, UK
and Dr Sergio Morera, Instituto Geofísico del Perú, Peru

Assisted by the Newton Fund

Water security means reliable access to water of good quantity and quality, and is central to both sustainable development and human and ecosystem well-being.

Water is perhaps the most exploited of natural resources, with around 70% of freshwater extraction used for agriculture. However, climate change, shifting land use practises, and economic growth are placing increased pressures on our intertwined water, food, and energy security.

Glaciers and ice sheets cover 10% of Earth’s surface, but contain 70% of global freshwater. This meltwater feeds many of the world’s great rivers, and supports hundreds of millions of people living downstream of areas like the Andes and Himalayas. But with global heating, many of these glaciers are retreating, threatening that water security.

The Cordillera Blanca in Peru is the most glaciated mountain range in the tropics, containing 25% of all the tropical mountain glaciers on Earth. But the area covered by glaciers has decreased by around 35% in the last 40 years alone.

For the Rio Santa, meltwater from the Cordillera Blanca provides 10-20% of river flow, but this can be more than 40% during the dry season, and even 90% during droughts. Our project set out to understand the challenges posed by both retreating glaciers and land and water use in this catchment.

As a glacier retreats in response to rising temperatures, meltwater production increases until the glacier shrinks to a critical size, leading to a reduction in river flow downstream. This point is termed “peak water” and has probably already passed for many glaciers in Peru.