根据考古研究(英语:Archaeology of the Americas)及遗传学分析(英语:Genetic history of indigenous peoples of the Americas),至少在24,500年前育空北部即有人类活动,而南安大略的人类活动可以追溯到公元前7,500年。旧克罗平地(英语:Old
to natural forces or human activity, there is now substantial evidence to indicate that human activity – and specifically increased greenhouse gas (GHGs)