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

Certainty of shift: Demonstrated
Location: Arctic, sub-Arctic, Asia, Europe, America
System Type: Ecological
Regime Shift Category: 2a
Ecosystem Type
Spatial Scale
Type of Resource Use
Number of Possible Regimes
Ecosystem Service
Time Scale of Change
Not Applicable
Resource Users
Reversibility of Shift


Alternate Regimes

1. Climate-biosphere system in colder tundra state

2. Climate-biosphere system in warmer boreal forest state

Fast or Dependent Variable(s)
Albedo and temperature
Slow or Independent Variable(s)
Vegetation type
Disturbance or Threshold Trigger(s)
Initial distribution of vegetation or other factors such as fire disturbance regimes
External / Internal Trigger


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.

Jacqui Meyers


CSIRO Sustainable Ecosystems,
PO Box 284,
Canberra ACT 2601

Ecosystem Feedback Mechanism, empirical data, Physical/Climate


Bonan, G. B., D. Pollard, and S. L. Thompson. 1992. Effects of Boreal Forest Vegetation on Global Climate. Nature 359: 716-18. (E)

Higgins, P. A. T., M. D. Mastrandrea, and S. H. Schneider. 2002. Dynamics of Climate and Ecosystem Coupling: Abrupt Changes and Multiple Equilibria. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences 357: 647-55. (D)