Methodology

This is a model, not a forecast. It exists to make the shape of the problem visible — how the pressures compound, how long the lag is between exposure and illness, and how much of the damage stops being reversible. Every number on the simulator traces back to the inputs below.

Starting state, 2026

These are plausible published-order figures for Lebanon, held in a single file so they can be replaced with verified national data without touching the model.

The seven pressures

How the model runs

• Air. The pressures set an equilibrium PM2.5 level; measured air drifts toward it by about 28% per year. Lost forest cover raises that equilibrium further, because thinning woodland stops scrubbing particulates.
• Land. Forest cover loses a share of itself each year to burning, loses a fixed amount to quarrying and construction, and regains ground only in proportion to how far fire pressure is reduced.
• Water and coast. Untreated discharge degrades drinking-water access and the shoreline index each year; treatment recovers them far more slowly than pollution destroys them. That asymmetry is deliberate and is the single most important feature of the model.
• Health. Respiratory illness and childhood asthma track air quality with a multi-year lag. Cancer incidence follows cumulative exposure, so it keeps climbing for years after the air improves. Premature deaths combine an air-pollution dose-response curve with water-borne mortality.
• Irreversibility. A ratchet. It rises with forest loss, coastal collapse, aquifer damage and cumulative exposure, and it never falls — pulling every slider to zero in 2040 does not give back what was already lost.

What this cannot tell you

It carries no regional resolution beyond illustrative city markers, no economics, no climate feedback from outside Lebanon, and no uncertainty bands. Treat the direction and the relative weight of each factor as the message; treat any single figure as indicative only.