Thresholds Database > Climate-biosphere system with vegetation type, Arctic and Sub-Arctic

Background

Alternate Regimes

1. Climate-biosphere system in colder tundra state

2. Climate-biosphere system in warmer boreal forest state

Mechanism

This study describes the boreal forest-tundra boundary in a positive feedback system. Boreal forest decreases albedo relative to tundra, thereby increasing total net surface radiation and temperature. The presence of trees masks the high reflectance of snow. Simulations suggest that boreal forests raise both winter and summer temperatures relative to tundra, leading to conditions more favourable for boreal forest. Tundra has a higher albedo, which decreases net radiation and temperature, thereby leading to conditions more favourable for tundra.

Management Decisions in Each Regime

Future changes to the distribution of boreal forest and tundra vegetation, such as from extensive logging or the influence of global warming, could alter the climate feedback mechanisms.