Quantifying water cycle feedbacks in engineered aerosol warming of Mars

Determine the nature, magnitude, and net sign of water cycle feedbacks in the climate of present-day Mars when warmed by near-surface release of engineered aerosol particles (graphene disks and aluminum nanorods), including potential effects from increased water vapor greenhouse forcing, water ice cloud radiative feedbacks, redistribution of ground ice under warming, and cloud-mediated scavenging of the engineered aerosols, to assess their impact on achieving and sustaining global warming targets.

Background

The paper models warming Mars using engineered aerosols (graphene disks and aluminum rods) and explicitly disables the water cycle in its 3D simulations to focus on radiative–dynamical feedbacks. The authors note several pathways by which the water cycle could interact with aerosol warming: water vapor greenhouse amplification, radiative impacts of water ice clouds, ground ice redistribution affecting melt timing, and the possibility that clouds could scavenge engineered particles acting as ice nuclei or cloud condensation nuclei.

Because these interactions were not included in the simulations, the overall effect of water cycle feedbacks on engineered-aerosol warming efficiency and stability remains uncertain. The authors therefore explicitly list water cycle feedbacks among the open questions that must be addressed to evaluate the viability and controllability of Mars warming using engineered aerosols.