Canada’s Glacial Coverage: A Journey Through Time
Canada’s Glacial Coverage: A Journey Through Time
During the last Ice Age, approximately 90% of Canada was covered by glaciers. This period, which peaked around 20,000 years ago, saw massive ice sheets, including the Laurentide Ice Sheet, dramatically transform the landscape and shape the geography of present-day Canada.
The Impact on Geography
The Laurentide Ice Sheet, one of the largest glacial formations, extended over much of Canada, particularly affecting regions such as Quebec, Ontario, the northern parts of the Prairie provinces, and the Yukon. This extensive coverage created striking features like the Great Lakes and various landforms such as moraines and drumlins. With the gradual warming of the climate, these glaciers began to retreat, leaving behind the landscape that can be observed today.
The Extent of Glacial Coverage
At the height of the most recent glaciation, ice completely covered Canada and extended a relatively short distance into the U.S., reaching further south in the interior of the continent, but not as far south on the coasts. The west coast saw less ice coverage compared to the east coast. The basins of the Great Lakes were carved out by the glacial movement, and the ice extended just short of the Ohio River. East of the Great Lakes, the ice extended as far south as New York City. Furthermore, west of the Great Lakes, the ice movement headed roughly diagonally up toward Canada, reaching close to the border by the Dakotas, then paralleling it to the Pacific.
Current Glacial Scenarios
Mark Ouellette's assertion is inaccurate. Indeed, Canada was covered by massive ice sheets during the peak of the last Ice Age about 20,000 years ago. However, it is important to note that we are currently in an inter-glacial period known as the Holocene, which falls within the larger Quaternary Ice Age. The Holocene began about 11,700 years ago and is characterized by generally warmer and more stable climate conditions.
Most of Canada has warm summers and cold, snowy winters, with a fairly short growing season. This climate is conducive to the formation of various types of glaciers, but it has little to do with the extensive ice cover seen during the last glacial period. Today, whereas almost all of Canada was covered by ice during the last glacial period, glaciers now cover only a small fraction of the country. This is due to natural climatic and geological processes, not direct human intervention in the climate.
Glacial Coverage During the Holocene Optimum
During the Holocene Optimum, a warmer period in the Holocene, glaciers in Canada were significantly less extensive than they are today. Studies have shown that at this time, Canada had fewer glaciers compared to today. The cryosphere and biological evidence indicate that glaciers were more reduced during the Holocene Optimum than they are at present. For instance, species such as the water chestnut and the pond turtle were north of their current European climatic limits, suggesting warmer conditions. Moreover, the treeline in Canada, as well as in other regions of the world, had not yet reached its maximum latitude or altitude during this period.
Future Prospects
Given that current temperatures are within the registered bounds for Holocene temperatures, we can conclude that the current glacial coverage in Canada is within the range of natural variability. Natural factors are responsible for the melting and formation of glaciers, and there is no evidence to suggest that the current melting is unusual. The glaciers in Canada are currently in a melting phase, but they are not down to the level of the Holocene Optimum.
However, it is undeniable that human activities, particularly the burning of fossil fuels and industrialization, contribute to rising global temperatures and may delay the next glacial period. Despite this, the Quaternary Ice Age is expected to continue for millions of years, as we are in a phase between glacial periods known as an inter-glacial period.
In summary, while the last Ice Age saw vast areas of Canada covered in ice, the current glacial coverage is a result of natural processes. Understanding these natural cycles is crucial for comprehending the impact of climate change and the resiliency of the environment.