Nature-based Climate Solutions and Tropical Peatlands: A Pathway to Achieving NDCs

Nature-based climate solutions are now central to discussions at international forums such as the United Nations Conference of the Parties, aimed at limiting global warming to below 1.5°C. Tropical peatlands in Southeast Asia represent significant sources of greenhouse gas (GHG) emissions within the regional land sector and are crucial to achieving national emissions reduction targets under Nationally Determined Contributions (NDCs). However, current estimates of GHG emissions from these peatlands vary widely and remain a topic of debate. Accurate assessments of contemporary GHG balances and their driving factors are therefore essential to understanding the global climate implications of these ecosystems. Since 2016, we have been measuring GHG fluxes over intact forests, degraded forests, and Acacia crassicarpa fiberwood plantations, within the same peat landscape in Sumatra, Indonesia. Using the eddy-covariance technique, we have quantified net exchanges of CO2 and methane, complemented by flux chamber measurements for soil nitrous oxide emissions. This comprehensive approach aims to refine emission factors and develop high-resolution (Tier 3) estimates while exploring their links to environmental variables. Surprisingly, we find that net CO₂ fluxes at different groundwater levels from eddy-covariance studies are substantially lower than those derived from previous flux chamber and subsidence studies. Contemporary emissions from Acacia plantation on peat are lower than what the IPCC and Indonesian's FREL report. Acacia plantations have lower GHG emissions than degraded sites with similar average groundwater levels. Thus, establishing plantation forests on degraded sites reduces long-term GHG emissions; further, using tree biomass for bioenergy avoids fossil fuel burning. Finally, our results confirm that the net avoidance of GHG emissions through the conservation of remaining intact peat swamp forests makes a significant contribution to Indonesia’s NDC.