The meltdown is accelerating. The glaciers of western Canada are melting faster than expected, and will probably be largely gone by the end of the century. That is one finding of a study that, worryingly, suggests we are underestimating the future pace of mountain glacier melting around the world.

Shifting too fast for comfort (Image: Ron Erwin/All Canada Photos/Corbis)

The world has 200,000 glaciers, nearly a tenth of which are in British Columbia and Alberta in western Canada, where they cover an area of 27,000 square kilometres and have an average thickness of 112 metres. The glaciers in these two provinces are losing almost one per cent of their volume each year – among the fastest rates of mountain ice loss anywhere in the world.

Until now, estimates of mountain ice in western Canada have forecast that less than half of it would be lost by century’s end. Most of these studies, including those that the Intergovernmental Panel on Climate Change relies on, simply base their predictions on the difference between the amount of snow falling on the glacier at higher altitudes and the amount thawing lower down.


Garry Clarke of the University of British Columbia in Vancouver has made the first major assessment based on a detailed analysis of how glaciers are likely to move and change shape as they melt. He concludes this will substantially speed up melting.

Clarke predicts that, under conditions forecast in most climate change scenarios, the region’s inland glaciers – including those in the Rocky mountains – will lose more than 90 per cent of their ice by 2100. The rate of ice loss is expected to peak in the next 25 years.

Glaciers on the coast will fare better, losing just 70 per cent. “The coastal glaciers receive considerably more precipitation,” says Clarke. “As long as winter precipitation lands as snow rather than rain, they will be well nourished.”

Andreas Vieli of the University of Zurich, Switzerland, backs Clarke’s approach. As the glaciers break up, gravity will move what remains of the ice from high, cold areas to lower areas where it will melt more quickly, he says.

The big melt will increase river flows in western Canada. Clarke calculates that flows will peak between 2020 and 2040, and then begin to dwindle creating problems for hydroelectric dams – including the 240-metre-high Mica dam on the Columbia River in British Columbia – which are built to exploit a particular size of seasonal flow.

Similar peaks and declines in river flows are likely to be a feature of the last days of glaciers elsewhere, including the rivers of central Asia and South America, Clarke says. We should not be misled by the big flows, he warns. “They will be a farewell message from the glaciers, not a sign of abundance.”

Journal reference: Nature Geoscience, DOI: 10.1038/ngeo2407