Feedbacks of Alpine Wetlands on the Tibetan Plateau to the Atmosphere

Abstract

The alpine wetlands of the Tibetan Plateau (TP) contribute 30%–40% of China’s natural wetlands, and they are experiencing changes in climate, i.e. warming of 0.26 °C 10 yr−1 (since the 1950s), as well as considerable human impacts. Consequently, alpine wetland extent show strong response to these impacts in most part, a reduction since the 1970s, followed by a recovery since the 2000s. In the eastern TP, they suffered stronger human regulations in Zoige mires, i.e. decades’ drainage and recent restoration. These alpine wetlands have long been considered as a vital CH4 source, while inventories and model simulations estimated these wetlands emit roughly 1 Tg CH4-C yr−1 and predicted an increase due to increased temperature and recovery of wetland extent. The alpine wetlands are generally a CO2 sink of roughly 15.8 Tg CO2 yr−1, mitigating half of their emitted CH4, and satellite-based observations of vegetation greening have observed that their plants took more CO2 from the atmosphere. Furthermore, the alpine wetlands provide a biophysical cooling effect, due to higher evaporative energy loss during early growing seasons. Variations in both climate changes and human influences have been well documented and indicate that these alpine wetlands provide vital feedbacks to the climate.