CH4 and N2O may contribute more to greenhouse effect than CO2 emission from the SCS

Abstract

The South China Sea (SCS) is the largest marginal sea in the world. It is now apparent that in summer tropical seas, such as the SCS, are either close to neutral or are a small source of CO2 to the atmosphere. Methane (CH4) and nitrous oxide (N2O), however, are clearly much more supersaturated in the SCS. In the case of the SCS, the CH4 and N2O released from the surface waters contribute about three times as much to the greenhouse effect as CO2 does. In addition, abnormally high subsurface CH4 concentrations were found on the continental slopes in the northern SCS, as CH4 have been released from sediments and/or may have originated in CH4 gas hydrates. CH4 gas hydrates might become an important source of energy in the future. However, will the buried CH4 be released either due to the warming of the seawater, the internal waves, tropical storms or other disturbances? It may compound the severity of global warming