The impacts of Stratospheric Aerosol Injection on Antarctic ice loss
depend on injection location
Abstract
Owing to increasing greenhouse gas emissions, the West Antarctic Ice
Sheet as well as a few subglacial basins in East Antarctica are
vulnerable to rapid ice loss in the upcoming decades and centuries,
respectively. This study examines the effectiveness of using
Stratospheric Aerosol Injection (SAI) that minimizes global mean
temperature (GMT) change to slow projected 21st century Antarctic ice
loss. We use eleven different SAI cases which vary by the latitudinal
location(s) and the amount(s) of the injection(s) to examine the
climatic response near Antarctica in each case as compared to the
reference climate at the turn of the last century. We demonstrate that
injecting at a single latitude in the northern hemisphere or at the
Equator increases Antarctic shelf ocean temperatures pertinent to ice
shelf basal melt, while injecting only in the southern hemisphere
minimizes this temperature change. We use these results to analyze the
results of more complex multi-latitude injection strategies that
maintain GMT at or below 1.5°C above the pre-industrial. All these cases
will slow Antarctic ice loss relative to the mid-to-late 21st century
SSP2-4.5 emissions pathway. Yet, to avoid a GMT threshold estimated by
previous studies pertaining to rapid West Antarctic ice loss
(~1.5°C above the pre-industrial), our study suggests
SAI would need to cool below this threshold and predominately inject at
low southern hemisphere latitudes. These results highlight the
complexity of factors impacting the Antarctic response to SAI and the
critical role of the injection strategy in preventing future ice loss.