Oceans and Glaciers
Global warming, accelerated by our high greenhouse gas (GHG) emissions, is causing the recession of glaciers and the melting of permafrost, which will lead to higher sea levels and change major ocean currents (1). Irreversible changes will be made to our planet if climate change is left uncontrolled.
Glaciers and ice sheets are important to the planet in many ways. Glaciers in Canada exist in the Canadian Arctic Archipelago, northern Labrador, and west of the Rocky Mountains. The Canada’s Changing Climate Report acknowledges their importance in offering fresh water for humans to use during snow and ice melt periods, impacting offshore and shipping systems, aiding transportation and extraction of resources in the north, and allowing for winter activities to be enjoyed (1). Under a medium emissions scenario, it is projected that glaciers across the mountains of western Canada will lose 74% to 96% of their volume by the late 21st century (1). Second, a major factor in the greenhouse effect is the ability of the Earth’s surface to reflect the sun’s radiation back into space rather than absorbing it– snow and ice are key factors in reflecting these rays (2). If surface ice melts, less of Earth’s surface will be reflective and more heat will be absorbed into the surface of the planet; warming the Earth further (3).
Third, glaciers are important as they store immense amounts of water. Water stored in glaciers and sea ice does not contribute to sea levels, but as temperatures rise, melting ice will release huge amounts of previously stored water into the oceans – something that will have major impacts on Canada and the rest of the world (1,4). Changes in sea levels are of major concern to people all over the world, due to the drastic effects it may have on the lives of millions of people. Estimates suggest that sea levels could rise by as much as five metres this century due to climate change, an amount which would put the majority of coastal cities underwater, including Vancouver, Tuktoyaktuk, and St. John’s, by 2100 (5). In addition to the drowning of many places, in other coastal cities, such as Halifax, devastating flooding will become more common (5). Warming will also cause severe flooding to occur in non-coastal cities more often. Recent flooding emergencies in Ottawa and Quebec are proof that the effects of climate change can already be seen in Canada (6). The Executive Summary of Canada’s Changing Climate Report 2019 discusses the issue of rising sea levels clearly: “Coastal flooding is expected to increase in many areas of Canada due to local sea-level rise” while “changes in local sea level are a combination of global sea-level rise and local land subsidence” or the lowering of the land from lack of underground support (7). Coastal cities are also vulnerable to the loss of sea ice in the Arctic and Atlantic Canada due to an increase in large storms and waves (7). A sudden addition of cold water to the ocean has the potential to interrupt vital ocean currents (8,9). The movement of a crucial circulation loop in the North Atlantic has slowed almost 15% in the past 50 years, and a 2019 study in the Journal of Climate shows that melting Arctic ice sheets are partially to blame for this phenomenon (8,9).
As well as melting sea ice and glaciers, global warming is capable of thawing permafrost soils (10). This can be disastrous to both people living in permafrost areas, and the natural environment surrounding them. A lot of the human infrastructure built in Arctic regions relies on permafrost to keep the ground stable; and, as it thaws, northern communities experience creeping disruption to daily life, including damage to building foundations, destabilization of roads, and increased risk of landslides (11). Further, there is potential for large amounts of methane to be released into the atmosphere as the permafrost thaws. As the ground heats up, large amounts of carbon dioxide and methane previously frozen in the soil are freed and released into the atmosphere, further contributing to warming - a detrimental positive feedback cycle (10). This risk is made worse by the large amount of northern forest fires.
The melting of glaciers and sea ice, thawing of permafrost, and the warming of the climate will worsen the warming effect through both absorption of energy by the earth and increased GHG emissions. This will force significant lifestyle changes for those in coastal or permafrost regions and damage necessary natural ocean circulation loops. As a northern country, Canada must be constantly aware of these effects and be prepared to create solutions.