Climate change silver lining? Retreating glaciers could create 6,000 km of Pacific salmon habitat

The melting of glaciers has resulted in the rising of sea levels and is contributing to the heating of the planet, but according to a new study, there may be one temporary benefit: melting glaciers could create new habits for Pacific salmon.

The study, published in the journal Nature Communications last week, looked at computer modelling of 46,000 glaciers between southern British Columbia and central Alaska and estimated that by the year 2100, the retreat of glaciers due to climate change could produce more than 6,000 kilometres of new habitat for Pacific salmon.

“On one hand, this amount of new salmon habitat will provide local opportunities for some salmon populations,” Kara Pitman, a spatial analyst with Simon Fraser University and the lead author on the study, said in a press release. “On the other hand, climate change and other human impacts continue to threaten salmon survival via warming rivers, changes in stream flows and poor ocean conditions.”

Pacific salmon have struggled under the pressure of climate change. Researchers with the University of British Columbia found just last summer that around 1,700 kilometres of streams once used by Pacific salmon are now dried up or inaccessible.

Fisheries and Oceans Canada also announced in June that nearly 60 per cent of commercial salmon fisheries were closing in a bid to combat the sharp decline of the species.

In this new study, which focused on glaciers, researchers ran five different models based on different climate change scenarios, spanning a 623,000-square-kilometre region.

They found that 315 of the glaciers they were looking at had the potential to provide streams ideal for salmon as they melted. Salmon, according to the release, require a steam connected to the ocean, which has a retreating glacier at its headwater and a “low-gradient slope of 10 per cent or less.”

If researchers accepted a 15 per cent stream gradient, 603 glaciers made the cut.

The 315 glaciers that were suitable for providing salmon habitats were also substantially larger than many of the other glaciers in the study, accounting for around 50 per cent of the overall glacier area in the study region.

The majority of the future salmon territory identified in the study was along the coast of Alaska and the very northern tip of B.C.

The regions in B.C. that could see new salmon habitats as glaciers retreats are likely to see them by 2050, according to the study, although the timing depends on the rate of climate change.

Although the creation of new salmon habitats appears to be a silver lining of the Earth’s warming, researchers cautioned that if the Earth continues warming at the same rate, these new habitats will also overheat and disappear the way existing salmon habitats are right now.

As glaciers retreat, salmon populations in southern regions of B.C. could also suffer as meltwater from glaciers diminishes.

“Climate change alters the shape and dynamics of stream ecosystems,” Diane Whited, a scientist with the University of Montana’s Flathead Lake Biological Station and an author on the study, said in the release. “This information is crucial for managing the future of salmon habitat and productivity.”