Year 0
You take office. The river is quiet. The forecast is not.
Port Meridian is a fictional coastal river city of 85,000 people with a local economy (gross metropolitan product) of $5.8 billion — about $68,000 per resident, typical of mid-sized U.S. metros. Its total city budget of roughly $215 million a year (~$2,500 per resident) is calibrated to real peers: Asheville, NC (pop. ~94,000) adopted about $250 million for FY2025. You have just been appointed to lead its Office of Resilience & Capital Planning for the next 30 years, in six five-year terms.
You control the city's resilience capital allocation — about $24 million a year, a tenth of the budget — from which debt service on $300 million of outstanding municipal debt (~$3,500 per resident, also typical) must first be paid. You may issue bonds to move faster — but debt service compounds, the city's credit rating reacts to its balance sheet, and every resilience dollar competes with schools, transit, and public safety for political support. Hazards arrive at random; climate change makes them gradually more severe. A do-nothing twin city faces the identical sequence, so you can see exactly what your portfolio earned — and when your 30 years are up, you can replay the exact same 30 years with a different strategy to separate skill from luck.
Frequent and corrosive. Repetitive-loss neighborhoods sit in the floodplain; indirect business-interruption losses follow every event.
Rare but catastrophic — wind and surge together. A major landfall can erase a decade of growth and spike public debt.
The quiet killer: low property damage, high mortality among isolated residents, real productivity losses. Worsens fastest with climate change.
The wildland-urban interface at the city's dry eastern edge. Smoke and evacuation costs ripple beyond the burn.
1. Each term, allocate your budget across nine evidence-based investment levers drawn from the published benefit–cost literature. 2. Issue bonds if you want to move faster — and accept the debt service. 3. Advance five years and watch the event log. 4. After 30 years, your scorecard compares you against the do-nothing twin: avoided losses, GDP, debt, lives, and a portfolio-level benefit–cost ratio at the discount rate of your choosing.
Tip: the highest returns in the literature are slow (codes need building-stock turnover) or unglamorous (enforcement, maintenance). The fastest political wins are not always the best economics — and vice versa.
What is a discount rate? It is how much less a future dollar is worth than a dollar today. Benefits that arrive decades from now — exactly when resilience investments pay off most — are "discounted" back to present value at this annual rate: at 3%, $1 of avoided losses in year 25 counts as about 48¢ today; at 7%, about 18¢. The choice matters enormously: the resilience literature typically uses ~3%, while federal hazard-mitigation grant analysis currently requires 7% (it was briefly 3.1% in 2023–25 before OMB reverted to the older standard). The slider is preset at 5% as a middle ground — move it and watch the verdict on the same 30 years change.
For educational use only. This simulator was developed for CLMT 5015: Climate Change Adaptation at the Columbia Climate School. Port Meridian is a fictional community; all events, outcomes, and trajectories are synthetic. The benefit–cost ratios, return-on-investment estimates, and economic relationships embedded in the model are drawn from publicly available sources, peer-reviewed literature, and independent modeling. They are approximations and should not be treated as audited, verified, or precise financial projections.
Nothing in this tool constitutes financial, investment, legal, or professional advice. Avoided-loss and return-on-investment figures are counterfactual estimates by nature and involve inherent uncertainty. Simulated resilience-investment outcomes are not indicative of real-world results in any actual jurisdiction.
Organization and program names referenced in the evidence base are the property of their respective owners and are cited for educational attribution only; their appearance does not imply endorsement of this tool.
AI assistance disclosure. This simulator was developed with the assistance of Claude, an AI assistant developed by Anthropic. AI assistance was used in the design, drafting, and implementation of the model and interface. All embedded figures and relationships were drawn from the sources cited below and should be verified against primary sources prior to external use. Apply the same critical judgment to AI-assisted tools as to any other secondary source.
References (Vancouver style; numbering follows the companion unit briefing):