Extreme weather events in Northern British Columbia are accelerating glacier melt at an all-time rate according to a recently published study.
According to the research led by University of Northern British Columbia (UNBC) researcher Dr. Brian Menounos, glaciers in western Canada and Switzerland experienced the largest mass losses on record over the past four years, due to early-season heat waves, prolonged dry conditions, low winter snow accumulation and surface darkening.
The findings were published in the peer-reviewed journal Geophysical Research Letters and revealed an acceleration in glacier melt rates in the regions between 2021 and 2024 that doubled the pace observed during the previous decade. Approximately 22.2 gigatonnes of ice per year were lost in western Canada and neighbouring American regions over the four-year period, which resulted in a 12 per cent decline in total ice volumes since 2020.
Switzerland lost 1.5 gigatonnes annually and has seen a 13 per cent decline in total ice volumes in the same period.
The total ice volume loss in North America would have enough meltwater to submerge the entire Toronto metropolitan area under 35 metres of water each year, according to the study.
鈥淓ven against the backdrop of rapid glacier loss since the start of this century, what we鈥檙e witnessing now is unprecedented,鈥� Menounos said.
鈥淭he melt rates over the last four years far exceed anything we鈥檝e observed in the past six decades, posing serious implications for freshwater availability, increased geohazard risks and the loss of cultural and tourism values tied to mountain landscapes.鈥�
Klinaklini Glacier, located on the central coast of B.C., is the largest glacier in western North America outside Alaska and is melting rapidly, losing about one gigaton of water each year. A weather station and camera were installed above the 470-square kilometre glacier by the Hakai Institute, providing data in near real time to scientists and operational users.
Menounos worked with scientists from the institute, Natural Resources Canada (Geological Survey of Canada), Environment and Climate Change Canada, the United States Geological Survey and researchers from Europe with funding from the Tula Foundation and the National Science and Engineering Research Council of Canada. They used airborne laser altimetry data from the Hakai Airborne Coastal Observatory, as well as other modelling and datasets, to calculate the loss of glacier mass reported in the study.
鈥淲e鈥檙e seeing the effects of meteorological events compounding one another 鈥� these conditions rapidly depleted snowpacks, exposing darker glacier ice and firn 鈥� multiyear snow 鈥� which can absorb more energy from sunlight and further accelerate melting,鈥� Menounos said. 鈥淲e believe these firn and ice surfaces are becoming darker from deposition of ash in Western North America and Saharan dust in Europe."
Menounos added that the darkening provides unhelpful feedback in a warming climate that will allow high melt rates to continue.
Other glaciers and icefields around the province that are areas of concern include Lloyd George Icefield west of Fort Nelson, Castle Creek Glacier near McBride, Tiedemann glaciers in the Coast Mountains, and glaciers in the Columbia River Basin. Meteorological measurements such as air temperature, wind speed, precipitation and humidity are being taken to better understand the controls of glacier nourishment and melt.
Researchers also measure changes in thickness, extent, volume and movement of hundreds of glaciers throughout the mountain ranges of western Canada, which requires analysis of thousands of aerial photos.
Based on projected rates of glacier mass loss until 2060, the study is consistent with previous research that suggested the period of peak runoff, when contributions of meltwater to rivers are at their highest, has likely already occurred and glacier streamflow will decline over the next few decades.
Menounos and other researchers are advocating for improved and advanced models that fully represent the response of glaciers to extreme weather events, as well as processes such as surface impurity deposition from dust and wildfires.
鈥淐urrent global models of glacier change do not include ways to track physical processes which lead to glacier darkening鈥�, he said. 鈥淚f we鈥檙e going to plan for the future, we need to improve our physical models to include [this] critical feedback."
