Adaptation Pathways Planner 2D: Sea-Level Rise & Tipping Points

⚠ ADAPTATION TIPPING POINT — choose the next pathway

Hazard Scenario

Sea-level-rise rate 10 cm/decade

Acceleration (uncertainty) 0.40

Simulation speed 2.0 yr/s

Defense Pathway

Live State

Year

2026

Hazard level

0 cm

Headroom

30 cm

Switches made

Cumulative adaptation cost

$0M

How it works

This is a simplified Dynamic Adaptive Policy Pathways (DAPP) model — the planning method used by real coastal programs (e.g. the Netherlands' Delta Programme, London's Thames Estuary 2100) to sequence climate defenses instead of betting on one fixed design.

Hazard:  H(t) = R·t + A·t²
  R = base rate (cm/yr), A = acceleration (cm/yr²)

Adaptation Tipping Point (ATP) for strategy i:
  the year t* where H(t*) = C_i  (design capacity)

At t*, strategy i is no longer sufficient — the plan
must switch to a strategy with C_j > H(t*), paying a
one-off transition cost.

Sea-level-rise rate — the linear component R of the hazard curve.
Acceleration — the quadratic term A; higher values mean the hazard curve bends upward faster, pulling tipping points forward in time (this stands in for climate-model uncertainty).
Pathway lanes — Seawall → Beach Nourishment & Dunes → Hybrid Green-Gray Infrastructure → Managed Retreat, each with a higher capacity ceiling and a higher switching cost, mirroring real adaptation-option hierarchies (gray → green/hybrid → retreat).
The chart — time runs along x, hazard/capacity along y. Dashed lines are each pathway's design-capacity ceiling; the thick colored line is the pathway actually walked, and yellow dots mark past tipping points. Drag the chart to pan through time, scroll/pinch to zoom — the strip below is a lane ladder showing which pathway is currently active and how much headroom it has left.

Real-world relevance: waiting until a fixed design is overtopped is far costlier than pre-committing trigger points and switching pathways early — the core argument for adaptive management under deep climate uncertainty.

drag = pan · scroll = zoom

Realized pathway (hazard) Adaptation tipping point Capacity ceiling (per lane)