LONDON, Sept. 18, 2017 – Glaciers cover one-tenth of the planet’s land surface – but not for much longer.
Glaciers worldwide are in retreat, and losing mass. They are shrinking and melting, and that will create problems almost everywhere, according to new research.
Between 2003 and 2009, glaciers melted on a gargantuan scale, with an estimated 1,350 cubic kilometres of meltwater streamed from what had once been vast streams of slowly flowing ice.
Ice has been in retreat in the Gulf of Alaska, the Canadian Arctic, Greenland and Antarctica. In the European Alps summers have become measurably warmer during the last 30 years, snowfall has diminished and 54% of the ice cover in the mountains has disappeared since 1850. By 2100, Alpine summits may have lost around nine-tenths of the ice that still covered them in 2003. In South America, the glaciers of Bolivia lost almost 50% of their mass in the last 50 years. In western Canada, somewhere between 60% and 80% of the ice measured in 2005 will have disappeared, and flowed into the sea to raise sea levels everywhere.
And, says an international team of scientists, in the Proceedings of the National Academy of Sciences, the loss of mountain ice creates problems for the people who live downstream.
“We don’t believe that the sheer enormity
of the impact of glacial shrinkage on our downstream
ecosystems has been fully integrated to date”
Glaciers in the basins of the Ganges, Brahmaputra and Indus rivers are right now losing 24 billion metric tons of ice a year: between 2003 and 2009, that added up to about a tenth of all the glacial ice lost everywhere in the world. Ice loss upstream means changes in the timing, magnitude and frequency of the flows downstream, and that in turn affects the levels of sediment, and the nutrients, both for the human populations who depend on the farmland in the valleys and plains below, but also for the natural ecosystems in the rivers, lakes and coastal zones.
It is time, the scientists argue, for some serious thinking: glacier loss cannot be separated from complexities such as changes in natural hazards such as flooding and drought, in agriculture, tourism, hydropower, cultural life and political economy.
“We don’t believe that the sheer enormity of the impact of glacial shrinkage on our downstream ecosystems has been fully integrated to date. From biodiversity to tourism, from hydropower to clean water supply, the breadth of risk to our current way of life is vast. The first step must be a realignment in how we view glacial shrinkage, and a research agenda that acknowledges the risk to regions likely to be most affected,” says Alexander Milner, professor of river ecosystems at the University of Birmingham in the United Kingdom, who led the study.
He and colleagues, from Alaska, Switzerland, Norway, Austria, France, Iceland, Denmark, Italy and other UK universities, want the global science community to think about four big things.
They want new technologies to map the details of ice loss with greater precision. They want better global monitoring of the nutrients and contaminants that are now trickling at ever greater rates from glaciers into downstream waterways.They want to see better understanding of the impact of what scientists like to call “ecosystem services” delivered by glaciers – and that includes what happens to salmon habitats and sports fisheries. And they would like to see management plans for change in the most sensitive glacier regions, and that could include international legislation to protect what they call “strategic glacier-derived water resources”.
They have firmly linked glacial loss to global warming driven by profligate human fossil fuel combustion and they have warned that such loss risks social change and potential catastrophe for millions.
So the latest study is a kind of summary of the research so far, and an attempt to identify what glaciologists, geographers, hydrologists and social scientists should do to understand the problems ahead, and identify steps to ameliorate some of the worst impacts. They see potential for conflict over access to dwindling water supplies downstream from what had once been great glacier systems.
And, they warn, there is even a religious dimension.
“For example, thousands of pilgrims annually traverse the Gangotri Glacier in India, considering it a sacred spot, and in Peru and the Yukon Territory of Canada, indigenous people consider glaciers as gods. In Peru, the loss of ice and snow from mountain peaks is thus associated with the god’s departure and the end of the world. On the Tibetan Plateau, residents consider the glacierised Yulong Snow Mountain their spiritual home, but already 65% have recognised the necessity to potentially migrate to adapt to climate change and achieve a sustainable livelihood,” they write.
“These social upheavals would clearly lead to implications across the wider array of services that human populations use from glacier-fed rivers.”