> Global warming swamps major delta
Global warming swamps major delta
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Lance Lesack, 778.782.3326, 604.219.5788 (cell), llesack@sfu.ca, Langley resident
Carol Thorbes, PAMR, 778.782.3035, cthorbes@sfu.ca
Lance Lesack, 778.782.3326, 604.219.5788 (cell), llesack@sfu.ca, Langley resident
Carol Thorbes, PAMR, 778.782.3035, cthorbes@sfu.ca
April 2, 2008
A new study co-authored by Simon Fraser University geographer Lance Lesack indicates that rising water levels induced by global-warming in the Northwest Territories’ Mackenzie Delta is three times more severe than predicted.
The study, Effects of global change on Canada’s Mackenzie River Delta, also co-authored by Environment Canada scientist Philip Marsh, was featured in a recent issue of Geophysical Research Letters, an international geoscience publication. The study is part of an International Polar Year investigation that is looking at the Arctic hydrological (water) cycle and freshwater ecosystems.
Lesack and Marsh are worried that the faster-than-predicted changes in the Mackenzie Delta could wreak havoc on human and animal life and industry in the region. It is about a third the size of Switzerland. Reaching 200 kilometres inland, the delta sits at the end of Canada’s longest river and sustains 45,000 lakes.
Lesack’s and Marsh’s latest study set out to verify their 1997 prediction that global warming could cause a drying out of the lakes that are sustained by river flooding caused by ice jams. Such lakes cover 15 per cent of the delta.
The pair also predicted that sea-level rise in the Arctic Ocean would cause water levels to slowly rise in the delta's lowest elevation lakes. Such lakes cover 60 percent of the delta.
Both predictions were correct. But what Lesack and Marsh didn’t expect is a 30-centimetre rise over the past 30 years in the water levels of the delta’s lowest elevation lakes. That is three times higher than sea-level rise at the arctic coast over the same period. A possible explanation is that global warming is melting arctic sea ice that normally suppresses coastal storm surges caused by winds over the Arctic Ocean. Consequently, storm surges are bigger, last longer and flood into low-lying areas such as the Mackenzie Delta.
The delta is home to important native communities and oil and gas exploration sites, and is a biological hotspot in the circumpolar arctic with abundant and diverse aquatic birds, fish and mammals. “The changes in both high and low water levels could change the biodiversity of this important ecosystem,” warns Lesack. "First Nation communities have already noticed changes, and there is little time to find ways to mitigate the impact of proposed gas development projects."
Lesack notes: “What is happening in the Mackenzie Delta is of world importance. It is a harbinger of what is likely happening in other circumpolar arctic deltas, where little is known about the impact of global warming.”
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The study, Effects of global change on Canada’s Mackenzie River Delta, also co-authored by Environment Canada scientist Philip Marsh, was featured in a recent issue of Geophysical Research Letters, an international geoscience publication. The study is part of an International Polar Year investigation that is looking at the Arctic hydrological (water) cycle and freshwater ecosystems.
Lesack and Marsh are worried that the faster-than-predicted changes in the Mackenzie Delta could wreak havoc on human and animal life and industry in the region. It is about a third the size of Switzerland. Reaching 200 kilometres inland, the delta sits at the end of Canada’s longest river and sustains 45,000 lakes.
Lesack’s and Marsh’s latest study set out to verify their 1997 prediction that global warming could cause a drying out of the lakes that are sustained by river flooding caused by ice jams. Such lakes cover 15 per cent of the delta.
The pair also predicted that sea-level rise in the Arctic Ocean would cause water levels to slowly rise in the delta's lowest elevation lakes. Such lakes cover 60 percent of the delta.
Both predictions were correct. But what Lesack and Marsh didn’t expect is a 30-centimetre rise over the past 30 years in the water levels of the delta’s lowest elevation lakes. That is three times higher than sea-level rise at the arctic coast over the same period. A possible explanation is that global warming is melting arctic sea ice that normally suppresses coastal storm surges caused by winds over the Arctic Ocean. Consequently, storm surges are bigger, last longer and flood into low-lying areas such as the Mackenzie Delta.
The delta is home to important native communities and oil and gas exploration sites, and is a biological hotspot in the circumpolar arctic with abundant and diverse aquatic birds, fish and mammals. “The changes in both high and low water levels could change the biodiversity of this important ecosystem,” warns Lesack. "First Nation communities have already noticed changes, and there is little time to find ways to mitigate the impact of proposed gas development projects."
Lesack notes: “What is happening in the Mackenzie Delta is of world importance. It is a harbinger of what is likely happening in other circumpolar arctic deltas, where little is known about the impact of global warming.”
— 30 —