what were a few of these major ages?
At least five major ones - the Huronian, Cryogenian, Andean-Saharan, late Paleozoic, and the latest Quaternary Ice Age
Ice age
There have been at least five major ice ages in the Earth's history (the Huronian, Cryogenian, Andean-Saharan, late Paleozoic, and the latest Quaternary Ice Age). 
the climate of canada can best be described as __ UNANSWERABLE what is climate? It is the long-term average of weather, typically averaged over a period of 30 years. are there models to represent this ? Yes, these models use quantitative methods to simulate the interactions of the atmosphere, oceans, land surface and ice. is this changing? Yes, the Earth has undergone periodic climate shifts in the past, including four major ice ages. how can these ages be defined? This is a long period of reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers.
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Ice age [SEP] Major ice ages
There have been at least five major ice ages in the Earth's history (the Huronian, Cryogenian, Andean-Saharan, late Paleozoic, and the latest Quaternary Ice Age). Outside these ages, the Earth seems to have been ice free even in high latitudes; such periods are known as greenhouse periods. Rocks from the earliest well established ice age, called the Huronian, formed around 2.4 to 2.1 Ga (billion years) ago during the early Proterozoic Eon. Several hundreds of km of the Huronian Supergroup are exposed 10–100 km north of the north shore of Lake Huron extending from near Sault Ste. Marie to Sudbury, northeast of Lake Huron, with giant layers of now-lithified till beds, dropstones, varves, outwash, and scoured basement rocks.