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Bolivia’s water supplies threatened by global warming

What’s happening? The Tuni glacier in Bolivia is shrinking more quickly than previously estimated, which is likely to intensify the water shortages already being experienced in the capital, La Paz, according to scientists from the Universidad Mayor de San Andres. Mountain ice feeds rivers, which provide crop irrigation and 20% of La Paz’s water supply. The glacier, which had been expected to exist through to 2025, has now been reduced to 1 sq km and is set to disappear imminently, the scientists claim. Climate change has accelerated the glacier’s disappearance, according to the researchers.

Why does this matter? Glaciers across the world are shrinking at rapid rates, exacerbated by rising temperatures. The melting of glaciers and ice sheets carries substantial implications for rising sea levels and water availability to downstream communities.

Bolivia’s Tuni glacier has lost an estimated 23 billion tonnes of ice each year over the past 20 years, as the frequency and unpredictability of extreme weather such as drought and torrential rain in the region has risen. Glacier shrinkage also threatens much larger water supplies, such as the world’s major “water towers” – 78 mountainous regions that generate, store and release large amounts of water from ice in a controlled manner. The Indus basin, for instance, provides water to over 200 million people in countries such as China, Afghanistan and Pakistan. Due to pressures such as growing water demand, climate-induced supply issues and potential geopolitical tensions, around 20% of the global population – or 1.9 billion people – could be negatively affected by projected changes to these water tower systems.

Glacier ice loss rates, which have seen 28 trillion tonnes of ice disappear since 1994, are aligned with the Intergovernmental Panel on Climate Change’s worst-case scenario that suggests a potential one-metre sea level rise by 2100 – as well as further increased temperatures as Earth’s ability to reflect solar radiation is reduced. Extreme glacier loss is increasingly being linked to human activity.

From an ecological perspective, glacial rivers provide a surprising and crucial purpose aside from supplying water – the ability to remove CO2 from the atmosphere. Rivers made up of glacial meltwater from High Arctic Canadian glaciers were found to absorb atmospheric CO2 40 times more efficiently than rainforests in the Amazon due to chemical weathering, scientists recently discovered. As such, from a carbon sequestration standpoint, preserving glaciers will also keep more CO2 out of the atmosphere.

Some last-ditch approaches to tackle melting glacier ice include wrapping smaller glaciers in duvets to keep ice cooler and reflect solar radiation, which was piloted on China’s Dagu glacier by scientists at the Chinese Academy of Sciences. Elsewhere, scientists have explored ideas including using artificial snow to cover surfaces on the West Antarctic Ice Sheet, using wind turbines to power the pumping of seawater 1,500 meters to the surface to be frozen and prevent further collapses of the ice sheet.

Of course, global large-scale action to address climate change, by curbing greenhouse gas emissions, is required to provide a long-term solution.

Lateral thought from Curation – As the article above notes, glaciers also provide water used for large-scale irrigation of crops.

We’ve previously highlighted how disruption to the food supply can lead to social unrest. It is unlikely people will sit idly by if they find themselves without food and water. Increasing instances of protest and disturbances could rise in lock-step with climate change, presenting an additional risk to global governments.

Katie Chan

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