It is estimated that, globally, nearly 30% of the soil organic carbon is locked in tundra and boreal ecosystems. Since approximately 75% of Canada is comprised of these ecosystems, a significant portion of the world's carbon occurs in Canadian territory. As shown in Map 8, most, (88% or 232 Gt) of the organic carbon found in Canadian soils occurs at mid and high latitudes (northward from the southern limit of the boreal forest) where cryosolic and organic soils dominate. At lower latitudes Canada's agricultural lands contain substantial amounts of organic carbon (about 9.36 Gt) representing nearly 6% of total organic carbon in all agricultural soils worldwide.

Map 8 larger image [GIF, 122.7 kb, 705 X 531, notice]

It is predicted that, as a result of climate change, the greatest increase in temperature will occur in northern latitudes, which could trigger serious degradation of organic and cryosolic soils. It is likely that these soils, which now act as carbon sinks, will become a source of CO2 and methane, further increasing the greenhouse gases and, therefore, climate change. In all ecosystems, the soil organic carbon is highly dynamic and affected by land use (e.g., soil and crop management), forest fires and clear-cutting of forests.

Contact:

Charles Tarnocai and Barbara Lacelle
Eastern Cereal and Oilseed
Research Centre
Agriculture and Agri-Food Canada
960 Carling Avenue,
Ottawa, ON
K1A 0C6
613-759-1857
Email: tarnocaict@em.agr.ca