Thirteen thousand years ago, glaciers that formerly extended to the edge of the continental shelf had retreated to the positions shown here. Offshore, several islands existed, (shown as green), the largest of which was on the Grand Banks of Newfoundland. The islands disappeared 8000 years ago because of rising sea levels, except, of course, for Sable Island. When the ice melted about 10 000 years ago, climate reached its modern state; tundra was succeeded by forests of birch then spruce, pine, and maple and hemlock.

10 000 years of stability

Scientists now know that Earth's climate has been much more stable and far warmer during the last 10 000 years than at any other time in the last 100 000 years. This remarkable stability has allowed human society to flourish. Even so, there have been changes in climate over this period, with far-reaching effects.

Did you know?
Vikings settled Greenland during a warm period, when climate was much like it is today - the so-called 'Medieval Warm Period' between 1000 AD and 1200 AD. Climate cooled in the thirteenth and fourteenth centuries, forcing Vikings to abandon their Greenland settlements.

Global temperature change over 10000 years. (Source : Environment Canada, based on data from Mann et al.)

How can we be sure that the warming of the last two decades is not related to the natural rhythm of climate?

References

Folland, C.K., Karl, T.R., and Vinnikov, K.Ya. 1990: Observed climate variations and change; in Climate Change: the IPCC (Intergovernmental Panel on Climate Change) Scientific Assessment, Cambridge University Press, p. 195-238.

Mann, M.E., Bradley, R.S., and Hughes, M.K. 1999: Northern hemisphere temperatures during the past millennium: inferences, uncertainties, and limitations; Geophysical Research Letters, v. 26, no. 6, p. 759-762.