12 December 2025 |  ZEROGeoengineering.com | “…Here, we use new climate model simulations to assess how effective SAI could be if the altitude of release was lower, including at altitudes within the reach of existing large jets. These lower altitude strategies must also inject at more polar latitudes, since the stratosphere is lower in the polar regions. Our results suggest SAI could meaningfully cool the planet even if using only existing jets, if injection is in the high latitudes during spring and summer. However, this low-altitude strategy requires three times more injection than high-altitude SAI, and so would strongly increase side-effects such as acid rain.”

Duffey, A., Henry, M., Smith, W.,Tsamados, M., & Irvine, P. J. (2025).Low‐altitude high‐latitude stratospheric aerosol injection is feasible with existing aircraft. Earth’s Future, 13,e2024EF005567. https://doi.org/10.1029/2024EF005567

“In this study we have assessed how and why global mean AOD, forcing and estimated cooling vary with injection strategy for SAI deployment over a wide‐range of latitudes and altitudes, stretching to a low‐altitude high‐latitude limit which has been little assessed previously. Change in the total aerosol burden, which arises from both changes in lifetime of aerosols in the stratosphere and the changes in the fraction of SO2 converted to H2SO4, is the dominant factor in controlling the variation in efficiency between strategies…

…In UKESM1, low‐altitude SAI using seasonal high‐latitude injection, could achieve substantial cooling with existing jets, albeit with around a third of the efficiency, and thus greater side‐effects per °C cooling, compared to high‐altitude injection. If this is the case, the substantially reduced technical barriers to acquiring capable deployment aircraft could imply a reduced barrier to entry for SAI…”

Link To  Low‐Altitude High‐Latitude Stratospheric Aerosol Injection Is Feasible With Existing Aircraft