Greenhouse gas emissions in natural and degraded tropical peatlands

High water table and anoxic conditions are the major drivers of the development of tropical peatlands. However, land-use change and degradation have severely disrupted their greenhouse gas exchange dynamics. Here, we synthesized published evidence to compare methane (CH₄), carbon dioxide (CO₂), and nitrous oxide (N₂O) fluxes between natural and degraded tropical peatlands and to evaluate their associations with hydrological, climatic, and soil variables. We found that degradation significantly reduced CH₄ emissions and increased N₂O emissions from peatlands. CO₂ emissions did not differ between natural and degraded from tropical peatlands. Water table emerged as an important factor regulating N₂O emission, while CH₄ and CO₂ emissions were significantly correlated with pH and soil carbon-to-nitrogen (C/N) ratio. These patterns represent synthesis-level associations, rather than direct mechanistic proof, because the datasets combine diverse land-use types and management histories. Our review highlights that greater attention should be directed toward the effect of drainage, fertilizer inputs, and fire events on tropical peatlands.