We measured CO2, CH4, and N2O gas fluxes from a pool of ultra-basic water discharging from serpentinized rock in Winterhouse Canyon, Gros Morne, Newfoundland. The flux of CH4 released and CO2 sequestered were calculated to be 4.6 × 10−7 and 1.9 × 10−5 mol/(m2·min), respectively, whereas N2O concentrations showed little change. The net radiative forcing owing to the changing concentrations of CO2 and CH4 during the sampling period was –0.21, suggesting that the ultra-basic pool in Winterhouse Canyon has a net cooling effect on the atmosphere. Similarly, the net global warming potential over a time horizon of 100 years was –7, also suggesting a small cooling of the atmosphere. Overall this study was the first to consider the impact of CO2 sequestration and CH4 emissions from an ultra-basic pool above serpentinized rock and demonstrated the need for more research on the net global impacts of serpentinization.