Overview

• Researchers evaluated stratospheric aerosol injection, seabed-anchored sea curtains, sea‑ice management (pumping seawater or scattering glass microbeads), basal water removal beneath glaciers, and ocean fertilisation.
• The study reports no robust real‑world evidence for effectiveness, severe logistical barriers in polar conditions, and timelines too slow to meaningfully counter accelerating ice loss.
• Estimated costs start at at least US$10 billion per concept, with sea curtains projected at about US$80 billion over 10 years for an 80‑kilometre installation.
• Identified risks include potential ozone depletion and climate pattern shifts from SAI, habitat and migration disruption from sea curtains, ecosystem harms from microbeads or pumping, contamination of subglacial environments, and uncertain ocean chemistry impacts from fertilisation.
• Governance gaps persist for SAI and sea‑ice management, other ideas face Antarctic Treaty and UN marine pollution constraints, and the findings have intensified a split between calls to prioritise decarbonisation and proponents of limited trials such as the ARIA‑funded Arctic sea‑ice pumping test planned for this winter.