ICE ACROSS BIOMES

Status and Trends

rapid loss of ice and frozen ground across biomes

data limited for some ice types and permafrost, but trends are clear

ecosystem consequences of ice loss

Status and Trends legend

KEY FINDING 7. Declining extent and thickness of sea ice, warming and thawing of permafrost, accelerating loss of glacier mass, and shortening of lake-ice seasons are detected across Canada’s biomes. Impacts, apparent now in some areas and likely to spread, include effects on species and food webs.

This key finding is divided into five sections:

• Key finding overview (this page)
• Sea ice
• Glaciers
• Lake and river ice
• Permafrost

Ice is a defining feature of Canada’s ecosystems – permafrost (frozen ground) underlies almost half the country. Arctic sea ice (increasingly seasonal) extends across the North and along parts of the east coast and most Canadian lakes and many rivers are seasonally frozen. Outside of the huge ice sheets of Antarctica and Greenland, Canada has the largest area of glaciers in the world (200,000 km²), of which 75% is in the Arctic Archipelago.¹

Ice ecosystems are important because they provide critical habitat for species adapted to living in, under, and on top of ice – from tiny one-celled organisms that live in the network of pores and channels within ice to polar bears. Sea ice helps regulate ocean circulation and air temperatures. Timing and duration of ice cover on rivers, lakes, and the sea are important factors in the types of plant and animal communities that water bodies support. Glaciers store fresh water and feed many of Canada’s largest rivers. Permafrost stores carbon and influences the structure of the landscape and storage and flow of water.

Global Trends

Worldwide, ice has been decreasing over the past several decades. Glaciers, including mountain glaciers that feed major rivers of China and India, are shrinking in mass and some have disappeared. Arctic sea-ice extent has decreased since 1979; Antarctic sea ice, while changing in some regions, does not show significant trends overall. Permafrost temperatures have increased in the past 20 to 30 years in most parts of the Northern Hemisphere.^{2, 3}