2024 January Newsletter

A Closer Look #236

Spain's Sierra Nevada with a water stream rushing down a mountainside.

Sierra to Sea: A high mountain stream in Spain’s Sierra Nevada, the southernmost glacial mountain range in Europe. Mountain headwaters and their downstream watersheds are threatened by changing snowfall and rainfall trends and increasing human impact. About half of humanity depends on mountain water towers (MWTs) for its water resources.

World’s Vanishing Mountain Water Resources are a Vital Loss to Humanity’s Reserves

Freshwater resources, and the myriad of ecosystem services they provide, are becoming increasingly critical under the combined assault of anthropogenic and climate change impacts. Such impacts are most visible for mountain water resources that are the source of most of the world’s streams, lakes, wetlands, and major rivers – the natural mountain water towers (MWT) of the world. Mountains, which cover about a quarter of Earth’s surface, provide more than half of the world’s freshwater resources. Mountain habitats also harbor over 80% of the world’s species of amphibians, birds, and mammals – many of which are exclusive to these regions. Mountain lakes, streams and rivers also sustain numerous fragile ecosystems such as riparian forests and biodiverse wetlands in their watersheds. MWTs play a vital role because of their world-wide distribution, coupled with an immense capacity for intercepting, capturing, and storing precipitation, and distributing it to lowlands over time. Rightfully called Earth’s Third Pole, Mountains that are glaciated and periglaciated (subterranean ice reserves), even out wet and dry periods by holding water in reserve in winter and releasing it during subsequent dry and hot summer months. However, because MWTs are particularly sensitive to intensifying anthropogenic impacts and ongoing climate change – high altitude ecosystems are warming faster than the global average and experiencing unprecedented ice loss – both mountain ecosystems and downstream communities face increasing water-related uncertainties.

A new peer-reviewed opinion piece in the September 2023 issue of Eos published by the American Geophysical Union addresses the subject of protecting the water resources of Spain’s Sierra Nevada Mountain range that is threatened by increasing anthropogenic land use and changing climate-driven precipitation patterns over the Mediterranean. It is part of the collaborative research AWRI’s Bopi Biddanda carried out as a Fulbright Senior Fellow at the University of Granada in Spain during 2022. In Spain, two University of Granada-led citizen-science projects involving the public and school children address the issue of safe-guarding the water resources of the Sierra Nevada. In the 74 High Mountain Glacial Lakes project, public report the status of the lakes to a common repository that creates maps of their health. The Rios de Vida program involves school children and their teachers in inventorying mountain streams and rivers in their neighborhoods, resulting in ecosystem assessments and timely public policy recommendations. Similar projects in other regions should help bring awareness to the plight of MWTs and help conserve MWT resources.

MWTs across the world such as the Rockies, Andes, Alps and Himalayas are similarly endangered. Their mountain-based glacial lakes, streams and rivers support a vast ecosystem of life in downstream all along their watersheds. However, the world’s MWTs, are projected to disappear by the end of the century and endanger the attainment of UN sustainable development goal of Clean Water and Sanitation, which aims to provide universal and equitable access to safe and affordable drinking water, sanitation, and hygiene by 2030. Thus, civilization is sleepwalking into this impending crisis of loss of freshwater availability in mountain-fed watersheds across the world. Furthermore, the loss of albedo (reflectivity) from the lack of snow and ice cover on world’s glaciers is expected to lead to a ramped-up positive loop of ever greater climate warming and accelerating glacier melt. We all live on a watershed. Even the Laurentian Great Lakes flow from the highlands around the upper lakes to the lower lakes in the lowlands, and eventually empty into the Atlantic Ocean via the St. Lawrence River. Society needs to become urgently aware of the factors driving the vanishing mountain water resources and its world-wide consequences from the sierras to the sea – and adopt timely mitigation and adaptation strategies.

Source Literature:

Biddanda, B. A., M. Villar-Argaiz and J. M. Medina-Sanchez (2023). Protecting the Mountain Water Towers of Spain’s Sierra Nevada. Eos, American Geophysical Union. 104 (9), 18-21. https://eos.org/wpcontent/uploads/2023/08/Sept23.pdf
https://eos.org/opinions/protecting-the-mountain-water-towers-of-spains-sierra-nevada



Page last modified February 22, 2024