## 1 Introduction  
The natural wetland ecosystem currently stores approximately one-fifth of the global soil carbon in the carbon cycle [1, 2]. Therefore, the natural wetlands are considered a long-term sink of carbon in cold regions [3]. For the Canadian wetlands, the carbon accumulation rate has been estimated at an average rate of 18-35 gm\({}^{-2}\) yr\({}^{-1}\). Therefore, a significant amount of carbon has accumulated in the wetlands in cold regions of Canada due to low rates of biomass production, while decomposition was inhibited by anaerobic respiration and low temperatures combined with higher groundwater levels [4]. The wetlands also have a great capacity to absorb carbon dioxide (CO\({}_{2}\)) via photosynthesis by the surface vegetation. Photosynthesis is higher than the decomposition and respiration rates where low temperatures enhance more biomass production than peat decomposition [5, 6]. However, climate change can increase CO\({}_{2}\) emission through peat decomposition and respiration in the wetland ecosystem. Increasing warming and drying conditions have a great impact on the balance between soil respiration and primary production, which in turn affect the CO\({}_{2}\) emission. This can lead to increased CO\({}_{2}\) emissions from wetlands and contributes to increased CO\({}_{2}\) emissions to the atmosphere in the global warming. Therefore, due to their increasing importance in the context of global warming, it is necessary to investigate the CO\({}_{2}\) emissions of wetlands in the cold region. Different models have been tested and applied to estimate greenhouse gas emissions (GHGs) in the aquatic and terrestrial ecosystems [7; 8]. The existing numerical models such as Daycent [9; 10], DENLEFWAT [11; 12], DNDC [13; 14], and ECOSYS [15; 16] have been applied to estimate GHGs emissions. These models are point-based models resulting in uncertainties while representing wetland processes at the watershed scale. Hydrological processes could be major factors influencing GHGs in wetlands. [PERSON] et al. [17] indicated that the carbon and water budgets of wetlands are interlinked. The Soil and Water Assessment Tool (SWAT) was used in predicting watershed processes for sustainable ecosystem management in a changing climate [18; 19; 20]. Recent research showed the SWAT has been modified for predicting nitrous oxide (N\({}_{2}\)O) released into the atmosphere [21] and for CO\({}_{2}\) emissions using microbially mediate soil organic matter (SOM) decomposition [22]. Although a simplified model of the wetland is included in the SWAT, the modeling of wetland processes is more sensitive to the impacts of climate change on GHGs due to drainage, snowmelt, wildfire, permafrost, and water table changes in cold climate regions [19; 23]. When the groundwater table decreases beyond a certain level, the decomposition rate increases, which enhances the wetlands as a source of CO\({}_{2}\) rather than a sink. The lowering of the groundwater table could change the wetlands to a large source of CO\({}_{2}\) and expose wetlands to aerobic conditions, leading to more decomposition rates [24; 25; 26]. [PERSON] et al. [27] reported that changes in snowmelt and glacial retreat due to climate change can substantially affect stream flows and freshwater resources. [PERSON] et al. [28] indicated the impacts of climate change on stream temperature and the aquatic ecosystem. [PERSON] and [PERSON] [29] simulated the dynamics of the groundwater table using the SWAT model to make predictions in Alberta, Canada. They [19] also estimated the effects of snowpack and soil temperature on CO\({}_{2}\) emissions in wetlands. Permanfrost in the cold regions exposes an immense amount of carbon and nitrogen stocks for decomposition. The wetland ecosystems, due to permafrost thawing and the freezing cycle, contribute significantly to CO\({}_{2}\) emissions [30; 31]. Furthermore, the land cover of the Athabasca Oil Sands Region (AOSR) is dominated by wetlands (\(\sim\)54% of total land cover).