Abstract
The Sanjiang Plain has been experienced significant wetland loss due to expanded agricultural activities, and will be potentially restored by the China National Wetland Conservation Action Plan (NWCP) in future. The objective of this study is to evaluate the impact of future climate warming and wetland restoration on wetland CH4 emissions in northeast China. We used an atmosphere-vegetation interaction model (AVIM2) to drive a modified biogeophysical model (CH4MODwetland), and projected CH4 flux variations from the Sanjiang Plain wetlands under different Representative Concentration Pathway scenarios throughout the 21st century. Model validation showed that the regressions between the observed and simulated CH4 fluxes by the modified model produced an R2 of 0.49 with a slope of 0.87 (p<0.001, n = 237). According to the AVIM2 simulation, the net primary productivity of the Sanjiang Plain wetlands will increase by 38.2 g m-2 yr-1, 116.6 g m-2 yr-1 and 250.4 g m-2 yr-1 under RCP 2.6, RCP 4.5 and RCP 8.5, respectively, by the end of this century. For RCP 2.6, 4.5 and 8.5 scenarios, the CH4 fluxes will increase by 5.7 g m-2 yr-1, 57.5 g m-2 yr-1 and 112.2 g m-2 yr-1. Combined with the wetland restoration, the regional emissions will increase by 0.18‒1.52 Tg. The CH4 emissions will be stimulated by climate change and wetland restoration. Regional wetland restoration planning should be directed against different climate scenarios in order to suppress methane emissions.
Highlights
Methane (CH4) is a very efficient greenhouse gas, with a Global Warming Potential of 25 on a 100-year time horizon, and is currently the second anthropogenic greenhouse gas after CO2 [1]
The wetland area is mainly vegetated with Deyeuxia angustifolia and Carex lasiocarpa plants, which account for about 20% and 80% of the vegetation in the Sanjiang Plain, respectively [55]
This study indicated that the net primary productivity (NPP) would increase by 7%, 28% and 63% under representative concentration pathways (RCPs) 2.6, RCP 4.5 and RCP 8.5 scenarios by 2100
Summary
Methane (CH4) is a very efficient greenhouse gas, with a Global Warming Potential of 25 on a 100-year time horizon, and is currently the second anthropogenic greenhouse gas after CO2 [1]. The radiative forcing of CH4 has been modified from 0.48 W m-2 [1] to 0.97 W m-2 [2, 3] when its indirect global warming effect was incorporated. Natural wetlands are the largest natural source in the present-day global CH4 budgets. They have emitted 100–231 Tg CH4 yr-1, PLOS ONE | DOI:10.1371/journal.pone.0158872. Prediction CH4 in Northeastern China technology special funds, (LTT, Data collection), CCSF201604, http://www.cma.gov.cn/en2014/, the Climate Change Special Foundation of China Meterological Administration, (LTT, Data collection). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
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