Century-Scale Effect of Climate Change on Meteorite Falls

TL;DR

This study models how climate change-induced atmospheric density changes over a century could affect meteorite fireballs and meteorite survival, finding only minor impacts on their brightness and mass.

Contribution

It provides the first simulation-based assessment of climate change effects on meteorite entry dynamics and survival over a century.

Findings

Catastrophic fragmentation occurs 300 m lower in future conditions.

Luminous flight terminates 190 m higher with minimal brightness change.

Meteorite survival mass decreases by only 0.1 g.

Abstract

Climate change is inducing a global atmospheric contraction above the tropopause (~10 km), leading to systematic decrease in neutral air density. The impact of climate change on small meteoroids has already been observed over the last two decades, with documented shifts in their ablation altitudes in the mesosphere (~50-85 km) and lower thermosphere (~85-120 km). This study evaluates the potential effect of these changes on meteorite-dropping fireballs, which typically penetrate the stratosphere (~10-50 km). As a case study, we simulate the atmospheric entry of the fragile Winchcombe carbonaceous chondrite under projected atmospheric conditions for the year 2100 assuming a moderate future emission scenario. Using a semi-empirical fragmentation and ablation model, we compare the meteoroid's light curve and deceleration under present and future atmospheric density profiles. The results indicate a modest variation of the ablation heights, with the catastrophic fragmentation occurring 300 m lower and the luminous flight terminating 190 m higher. The absolute magnitude peak remains unchanged, but the fireball would appear 0.5 dimmer above ~120 km. The surviving meteorite mass is reduced by only 0.1 g. Our findings indicate that century-scale variations in atmospheric density caused by climate change moderately influence bright fireballs and have a minimal impact on meteorite survival.