1. Introduction

Our planet is experiencing climate warming at an unprecedented rate that can be attributed to increasing atmospheric greenhouse gas concentrations (IPCC 2013). Methane (CH4) is the second most abundant greenhouse gas in the atmosphere after carbon dioxide (CO2) and has a greenhouse warming potential 25 times higher than that of CO2. Earth’s atmospheric CH4 concentration has risen approximately 150% since 1750 and is largely attributed to human activities (UCAR 2012, Figure 1).

Figure 1. Plot showing CH4 mole fraction (Methane Flux) in parts per billion (ppb) over a 40 yr period (Figure from NOAA).

Wetlands are an important natural source of CH4 to the atmosphere (Saunois, 2020).  Methane flux is dependent on both hydrology and temperature. Hydrology is influenced by climate and land-use practices. Because CH4 flux depends on both temperature and hydrology, it is unknown if an increase in temperature only can lead to an increase in methane emissions.

1.1 Our Study Area:

Figure 2. Study area map of the PPR (red boundary) spanning 3 Canadian provinces and 5 U.S. states.

            The PPR, covering over an area of approximately 770,000  km2, consists of depressions created by activity from the last glaciation maximum, ending approximately 10,000 years ago (Perry et al., 2020). These depressions fill with water to create permanent to semi-permanent wetlands. This area extends into five U.S. states: Minnesota, Wisconsin, Iowa, North Dakota, and South Dakota as well as three Canadian provinces: Alberta, Saskatchewan, and Manitoba, as seen in Figure 2 The Prairie Pothole Region (PPR) is one of the largest wetlands systems in the world and is an important part of the regional and perhaps global ecosystem (Perry et al., 2020). There is critical importance in studying the PPR due to the region’s impact on geology, biology, and chemistry as well as the ecosystem services they offer (Perry et al., 2020).

1.2 Why is CH4 flux from the PPR important?