Australian vegetated coastal ecosystems as global hotspots for climate change mitigation

TLDR

Policies aiming to preserve vegetated coastal ecosystems to mitigate greenhouse gas emissions require national assessments of blue carbon resources. The study aims to present organic carbon storage in Australian vegetated coastal ecosystems and estimate the potential annual CO₂ emission benefits of conserving and restoring these habitats. This was achieved by assessing organic carbon storage across Australian climate regions and estimating the potential annual CO₂ emission benefits of VCE conservation and restoration. Australia holds 5–11 % of global VCE carbon stocks (70–185 Tg C in aboveground biomass and 1,055–1,540 Tg C in the upper 1 m of soils), and current VCE losses could emit 2.1–3.1 Tg CO₂‑eq yr⁻¹, raising land‑use‑change CO₂ emissions by 12–21 %, underscoring the potential of VCE conservation and restoration to support national greenhouse‑gas mitigation policy.

Abstract

Abstract Policies aiming to preserve vegetated coastal ecosystems (VCE; tidal marshes, mangroves and seagrasses) to mitigate greenhouse gas emissions require national assessments of blue carbon resources. Here, we present organic carbon (C) storage in VCE across Australian climate regions and estimate potential annual CO 2 emission benefits of VCE conservation and restoration. Australia contributes 5–11% of the C stored in VCE globally (70–185 Tg C in aboveground biomass, and 1,055–1,540 Tg C in the upper 1 m of soils). Potential CO 2 emissions from current VCE losses are estimated at 2.1–3.1 Tg CO 2 -e yr -1 , increasing annual CO 2 emissions from land use change in Australia by 12–21%. This assessment, the most comprehensive for any nation to-date, demonstrates the potential of conservation and restoration of VCE to underpin national policy development for reducing greenhouse gas emissions.