Atmospheric and Climate Effects of Rocket Emissions

Scientific Background and Motivation

The environmental impact of emissions from space launches is currently receiving much attention (Dallas et al., 2020) due to the space industry being one of the fastest growing global economic sectors (Ryan et al., 2021). Since the first assessment of the impact of rocket emissions by Cicerone and Stedman (1974), there have been many developments in rockets and modelling. Rocket emissions can inject significant quantities of gases and particles into the atmosphere (including chlorine compounds HCl, H₂O, CO₂, NO_x, H₂, Al₂O₃ and black carbon), potentially affecting ozone depletion, the dynamics of the atmosphere, and climate change (e.g., Prather et al., 1990; Ross et al., 2009; Ross and Toohey, 2010; Larson et al., 2017; Maloney et al., 2022). Recently Feng et al. (2023) have investigated stratospheric ozone depletion due to the presence of small satellites (e.g., CubeSats) with an iodine propulsion system to keep them in orbit. They have shown that an increase in the number of small satellite launches could cause substantial ozone depletion in the Antarctic.

The extent of stratospheric ozone depletion will depend on the amount and nature of emissions into the atmosphere. However, in contrast to the Montreal Protocol, there is no regulation to control and limit the space launches to protect the atmosphere. Brown et al. (2023) have recently provided estimates of the global emissions from the four principal rocket propellants currently in use. Therefore, there is now a need to assess the impacts of the growing number of rocket launches using state-of-the-art models.

This PhD project will use a global chemistry-climate model (UKESM) to explore how rocket emissions affect the stratospheric ozone layer and climate once the gases and particulates from the rocket launches are injected into the atmosphere. The model includes dynamics, transport, aerosol microphysics, photochemistry, radiation, emissions, and their influences on stratospheric ozone depletion (Chipperfield et al., 2018; Feng et al., 2011, 2021). Thus the project will be able to assess the atmospheric changes induced by rocket emissions under historical and future scenarios (Figure 2).

 

Objectives:

The goal of this project is to answer a number key questions: How to estimate gas and particulate emissions from the rocket launches? How to evaluate the accuracy and uncertainties of the reported rocket emissions? How do rocket emissions affect stratosphere aerosol (ozone) layer and chemistry, and thus climate change under different scenarios (histoical and future) and for different types of fuel (solid, liquid kerosene etc)? Which important processes are missing in the current whole atmosphere models when Al₂O₃ emission is considered?

The student will work with scientists at Leeds and UK Met Office to apply a global earth system model (UKESM) with new capability for inclusion of rocket emissions and updated chemistry, and then evaluate the new models compared to available measurements.

Specific objectives will include:

1. Develop and improve UKESM by including a treatment of rocket emissions. Necessary updates include the chemistry and aerosol schemes for the black carbon and Al2O3 rocket emissions;
2. Validate the developed UKESM with available observations including satellite data, station observations etc;
3. Perform long-term simulations to investigate the impact of rocket emissions on stratospheric composition (chemistry and aerosol) as well as other climate variables (temperature, radiation etc) under different conditions from historic period to the future scenario;
4. Quantify the potential risks for rocket emissions on atmosphere and climate and provide suggestions for policy makers.

 

Potential for high impact outcome:

This project addresses the potential effects of various rocket emissions on atmosphere and climate change by developing UK Earth System Model (UKESM) to better understand the anthropogenic emissions, chemistry and physical processes that control atmospheric composition and aerosol in the whole atmosphere. The project is therefore likely to have significant impacts in a number of fields, including global atmospheric modelling, chemistry and aerosols.

 

Training:

The student will work principally under the supervision of Professor Martyn Chipperfield, Dr Wuhu Feng and Professor John Plane. This project will provide a high level of specialist scientific training in: (i) the application of a world-leading atmospheric chemistry-climate models; (ii) analysis and synthesis of large datasets; (iii) use of advanced High Performance Computing facilities (e.g. the UK national supercomputer archer.ac.uk, and the Leeds Advance Computing arc.leeds.ac.uk). The successful applicant will have an opportunity to visit UK Met Office for the model development, as well as attend training organised by the Doctoral Training Programme, the National Centre for Atmospheric Science, and attendance at national/international conferences.

 

References:

Brown T.F.M., M.T. Bannister and L.E. Revell (2023) Envisioning a sustainable future for space launches: A review of current research and policy, Journal of the Royal Society of New Zealand, https://doi.org/10.1029/2021EF002612.

Chipperfield, M. P., Dhomse, S., Hossaini, R., Feng, W., Santee, M. L., Weber, M., et al. (2018). On the cause of recent variations in lower stratospheric ozone. Geophys. Res. Lett., 45, 5718– 5726. https://doi.org/10.1029/2018GL078071.

Cicerone, R. J., and D. H. Stealman (1974). The Space Shuttle and other atmospheric chlorine sources, paper presented at the 6th Conference on Aerospace and Aeronautical Meteorology, Am. Meteorol. Soc., E1 Paso Tex., Nov. 12-15, 1974.

Dallas, J.A., Raval, S., Alvarez Gaitan, J.P., Saydam, S., Dempster, A.G., (2020). The environmental impact of emissions from space launches: A comprehensive review, Journal of Cleaner Production, 255, 2020, doi:10.1016/j.jclepro.2020.120209.

Feng, W., Dhomse, S. S., Arosio, C., Weber, M., Burrows, J. P., Santee, M. L., and Chipperfield, M. P. (2021). Arctic ozone depletion in 2019/20: Roles of chemistry, dynamics and the Montreal Protocol, Geophys. Res. Lett., 48, e2020GL091911, doi:10.1029/2020GL091911.

Feng, W., Plane, J. M. C., Chipperfield, M. P., Saiz-Lopez, A., & Booth, J.-P. (2023). Potential stratospheric ozone depletion due to iodine injection from small satellites. Geophys. Res. Lett., 50, e2022GL102300, doi:10.1029/2022GL102300.

Larson, E.J.L., Portmann, R.W., Rosenlof, K.H., Fahey, D.W., Daniel, J.S. and Ross, M.N. (2017). Global atmospheric response to emissions from a proposed reusable space launch system, Earth’s Future, 5: 37-48. doi:10.1002/2016EF000399.

Maloney, C. M., Portmann, R. W., Ross, M. N., and Rosenlof, K. H. (2022). The climate and ozone impacts of black carbon emissions from global rocket launches, J. Geophys. Res., 127, e2021JD036373. doi:10.1029/2021JD036373.

Prather, M. J., García, M. M., Douglass, A. R., Jackman, C. H., Ko, M. K. W., and Sze, N. D. (1990). The space shuttle’s impact on the stratosphere, J. Geophys. Res., 95, 18583–18590, doi:10.1029/JD095iD11p18583.

Ross, M., Mills, M., & Toohey, D. (2010). Potential climate impact of black carbon emitted by rockets, Geophys. Res. Lett., 37, L24810. doi:10.1029/2010GL044548.

Ross, M., Toohey, D., Peinemann, M. and Ross, P. (2009). Limits on the Space Launch Market Related to Stratospheric Ozone Depletion, Astropolitics, 7:1, 50-82, doi:10.1080/14777620902768867.

Ryan, R. G., Marais, E. A., Balhatchet, C. J., and Eastham, S. D. (2022). Impact of rocket launch and space debris air pollutant emissions on stratospheric ozone and global climate, Earth’s Future, 10, e2021EF002612, https://doi.org/10.1029/2021EF002612.

Shutler, J.D., Yan, X., Cnossen, I. et al. (2022). Atmospheric impacts of the space industry require oversight, Nat. Geosci., 15, 598–600, doi:10.1038/s41561-022-01001-5.