Journal Article

Impact of Rocket Launch and Space Debris Air Pollutant Emissions on Stratospheric Ozone and Global Climate

Eastham, Sebastian D., Ryan, Robert G., Balhatchet, Chloe J., Marais, Eloise A.

2022

Overview

Detailed examination of the impact of modern space launches on the Earth's atmosphere is crucial, given booming investment in the space industry and an anticipated space tourism era. We develop air pollutant emissions inventories for rocket launches and re‐entry of reusable components and debris in 2019 and for a speculative space tourism scenario based on the recent billionaire space race. This we include in the global GEOS‐Chem model coupled to a radiative transfer model to determine the influence on stratospheric ozone (O3) and climate. Due to recent surge in re‐entering debris and reusable components, nitrogen oxides from re‐entry heating and chlorine from solid fuels contribute equally to all stratospheric O3 depletion by contemporary rockets. Decline in global stratospheric O3 is small (0.01%), but reaches 0.15% in the upper stratosphere (∼5 hPa, 40 km) in spring at 60–90°N after a decade of sustained 5.6% a−1 growth in 2019 launches and re‐entries. This increases to 0.24% with a decade of emissions from space tourism rockets, undermining O3 recovery achieved with the Montreal Protocol. Rocket emissions of black carbon (BC) produce substantial global mean radiative forcing of 8 mW m−2 after just 3 years of routine space tourism launches. This is a much greater contribution to global radiative forcing (6%) than emissions (0.02%) of all other BC sources, as radiative forcing per unit mass emitted is ∼500 times more than surface and aviation sources. The O3 damage and climate effect we estimate should motivate regulation of an industry poised for rapid growth. Plain Language Summary It is imperative that we understand the current and future risks to Earth's atmosphere posed by pollution from rocket launches and re‐entry heating of reusable and discarded rocket parts and historical debris. Rockets, unlike other anthropogenic pollution sources, emit gaseous and solid chemicals directly into the upper atmosphere. We compile inventories of these chemicals from rocket launches in 2019 and projections of future growth and speculative space tourism activity. We incorporate these in a 3D atmospheric chemistry model to simulate the impact on climate and the protective stratospheric ozone layer. We find that loss of ozone due to current rockets is small, but that routine space tourism launches may undermine progress made by the Montreal Protocol in reversing ozone depletion in the Arctic springtime upper stratosphere. The BC (or soot) particles from rockets are also of great concern, as these are almost five hundred times more efficient at warming the atmosphere than all other sources of soot combined. These findings demonstrate an urgent need to develop environmental regulation to mitigate damage from this rapidly growing industry. Key Points Air pollutant emission inventory for current space sector and future tourism input to a coupled chemistry and radiative transfer model Upper stratospheric Arctic ozone loss from launch chlorine and re‐entry nitrogen oxide emissions undermines Montreal Protocol success Warming efficiency of space tourism (soot) emissions about 500‐times greater than surface and aircraft sources of soot

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc
• Subject: Air pollution / Analysis / Atmosphere / Atmospheric Composition and Structure / Aviation / Black carbon / Chlorine / Climate / Climate effects / Commercial space ventures / Depletion / Emission inventories / Emissions / Environmental aspects / GEOS‐Chem / Global climate / International aspects / Kerosene / Middle Atmosphere: Composition and Chemistry / Montreal Protocol / Nitrogen oxides / Ozone / ozone depletion / Ozone layer / Photochemicals / Pollutants / Radiation / Radiative forcing / Radiative transfer / Reusable components / Rocket launches / Rocket launching / Rockets / Solid fuels / Space debris / Space exploration / Space programs / Space tourism / Stratosphere / Tourism / Upper stratosphere