Increased System Vulnerability from the Downward Shift of the EDC

Narrowing Stability Margin from EDC Shift

Figure 8.30: Consequences of a Downward EDC Shift on System Stability

An ecological model describes the year-to-year extent of Arctic sea ice using a dynamic curve, which shows the relationship between the ice extent in one year and the extent in the following year. The model currently shows a stable equilibrium with high ice cover. Consider two scenarios:

Scenario 1: A single, unusually warm year causes a large amount of ice to melt, but long-term climate conditions remain unchanged. Scenario 2: A sustained, multi-decade trend of rising atmospheric and ocean temperatures occurs.

How would the model most accurately represent the distinct effects of these two scenarios on the sea ice system?

Modeling Long-Term Climate Impacts on Arctic Sea Ice

In a model of Arctic sea ice dynamics, a sustained increase in global average temperatures that makes each winter milder than the last is represented as a movement along a stable Environmental Dynamics Curve to a new, lower equilibrium point.

Analyzing a Shift in an Environmental System Model