Glacial Retreat Calculator

The calculator applies a temperature multiplier of 1 + 0.5 × tempAnomaly, so a 1°C anomaly multiplies your base retreat rate by 1.5 and a 2°C anomaly by 2.0. This 50%-per-degree figure is a simplified empirical sensitivity meant to be broadly representative of mid-latitude glaciers rather than a universal physical constant — actual sensitivity varies a lot by glacier geometry, so if you have a locally calibrated sensitivity value, treat this as a rough placeholder rather than a fixed law.

The elevation factor is 1 − (elevation − 3000) / 10000, which reduces the retreat rate for glaciers above 3,000 m (higher, colder, thinner ice melts more slowly) and increases it for glaciers below 3,000 m. The formula floors that factor at 0.3 so even a very high, cold glacier is never modeled as retreating less than 30% of its unadjusted rate — reflecting the fact that essentially all glaciers are losing some mass under current conditions rather than staying static.

That figure divides current glacier length by the effective retreat rate, which assumes the retreat rate stays constant every year of the projection. Real glaciers accelerate as they retreat: thinning ice melts faster, exposed rock and debris absorb more heat, and floating or lake-terminating glaciers can suffer sudden calving collapses — none of which this straight-line model captures, so the true timeline is often shorter than shown here, especially under continued warming.

Length loss is a direct subtraction, but volume comes from the Bahr et al. (1997) scaling relationship, where ice volume scales with glacier length raised to the power of about 1.375. That's because a glacier isn't a uniform slab — it's typically thicker toward the middle and thinner near the terminus, so losing a given fraction of length doesn't remove the same fraction of volume. The calculator applies this scaling law to both the original and remaining lengths and reports the difference as volume lost.