On the Anthropogenic and Natural Injection of Matter into Earth's Atmosphere

TL;DR

This paper compares human-made and natural matter entering Earth's atmosphere, highlighting the increasing significance of anthropogenic debris due to satellite activities and potential impacts on atmospheric and terrestrial environments.

Contribution

It provides a detailed comparison of natural and anthropogenic mass fluxes into Earth's atmosphere, emphasizing future risks from satellite constellations.

Findings

Anthropogenic material currently accounts for about 2.8% of natural mass flux.

Future satellite constellations could raise anthropogenic contribution to nearly 40%.

Anthropogenic injection of metals and aerosols may significantly impact Earth's atmosphere.

Abstract

Every year, more and more objects are sent to space. While staying in orbit at high altitudes, objects at low altitudes reenter the atmosphere, mostly disintegrating and adding material to the upper atmosphere. The increasing number of countries with space programs, advancing commercialization, and ambitious satellite constellation projects raise concerns about space debris in the future and will continuously increase the mass flux into the atmosphere. In this study, we compare the mass influx of human-made (anthropogenic) objects to the natural mass flux into Earth's atmosphere due to meteoroids, originating from solar system objects like asteroids and comets. The current and near future significance of anthropogenic mass sources is evaluated, considering planned and already partially installed large satellite constellations. Detailed information about the mass, composition, and ablation of natural and anthropogenic material are given, reviewing the relevant literature. Today, anthropogenic material does make up about 2.8 % compared to the annual injected mass of natural origin, but future satellite constellations may increase this fraction to nearly 40 %. For this case, the anthropogenic injection of several metals prevails the injection by natural sources by far. Additionally, we find that the anthropogenic injection of aerosols into the atmosphere increases disproportionately. All this can have yet unknown effects on Earth's atmosphere and the terrestrial habitat.