<p>Amazonian peat swamp forests remove large amounts of carbon dioxide (CO₂) but anaerobic decomposition of the peat produces methane (CH₄). Drought or cultivation cuts down on the CH₄ production but may increase the CO₂ emission. Varying oxygen content in nitrogen-rich peat produces nitrous oxide (N₂O). Despite the potentially tremendous changes, greenhouse gas emissions from peatlands under various land uses and environmental conditions have rarely been compared in the Amazon. We measured CO₂, CH₄ and N₂O emissions from the soil surface with manual opaque chambers, and environmental characteristics in three sites around Iquitos, Peru from September 2019 to March 2020: a pristine peat swamp forest, a young forest and a slash-and-burn manioc field. The manioc field showed moderate peat respiration and N₂O emission. The swamp forests under slight water table drawdown emitted large amounts of CO₂ and N₂O while retaining their high CH₄ emissions. Most noticeably, a heavy shower after the water-table drawdown in the pristine swamp forest created a hot moment of N₂O. Nitrifier denitrification was the likely source mechanism, as we rule out nitrification and heterotrophic denitrification. We base the judgement on the lack of nitrate and oxygen, and the suppressed denitrification potential in the topsoil. Overall, our study shows that even moderate drying in Peruvian palm swamps may create a devastating feedback on climate change through CO₂ and N₂O emissions.</p>