## 3 Discussion  
In terms of their ecosystem functions, peatlands are a valuable element of the natural environment, so it seems essential that they are preserved in their natural, non-degraded form. Peatlands are responsible for retaining carbon, generating biomass, and storing water, and constitute extremely valuable natural habitats of flora and fauna [1; 102; 103; 104; 105]. Thus, it is important to continuously examine the state of the peatland environment repeatedly and systematically, which is facilitated by, inter alia, the application of RS methods. Trends in the development of existing peatlands cannot be forecast without investigating their history and determining their transformation rate. The evolution of peatlands can result from climate change and the natural 'ageing' of these ecological accumulation systems [106; 107; 108], as well as increasing anthropopressure [108; 109; 110; 111; 112]. Palaeecological research on peatland and lake sediments increasingly uses a multi-proxy approach [105; 113; 114; 115; 116; 117; 118; 119]. A comparison of results from multiple analyses (e.g., palynological, macrofossil, testate amoebae analysis, \({}^{14}\)C and \({}^{210}\)Pb dating) provides a broader view of events in the history of the ecosystem [114; 116; 118; 120; 121]. In studies on the past and the life cycle of peatlands, the authors used palaeobotanical, palaeozological and chronometric methods to learn about the history of the area and its past climatic state. In order to be able to conduct such research, it is necessary to identify the location and borders of peatland, which are facilitated by the application of RS methods. In their study, [PERSON] et al. (2012) [122] emphasise the importance of peatland research in terms of analysing the climatic past. However, the authors do not seem to acknowledge the applicability of remote sensing methods in the analysis of peatlands. The rapid acceleration of climate warming in recent decades necessitates the implementation of the systematic and global monitoring of peatlands, which function as a carbon storage system. Gross primary productivity and greenhouse gas emissions significantly influence climate change [27; 28; 29; 46; 66]. As demonstrated in our analysis, an increasing number of studies successfully employ remote sensing and advocate for the efficiency of this method in estimating carbon resources and CO\({}_{2}\) emissions in peatlands [27; 28; 29; 40; 46; 62; 66; 74]. In the case of peatland areas, the settling of peat correlates with peat thickness as peatlands dry up and are supplied with water [123; 124]. Estimates found in the available literature regarding the rate of CO\({}_{2}\) release caused by peat settling tend to vary considerably: 20 Mg CO\({}_{2}\) ha\({}^{-1}\) year\({}^{-1}\)[125], 58.4-74.5 Mg CO\({}_{2}\) ha\({}^{-1}\) year\({}^{-1}\)[126], 72.7 Mg CO\({}_{2}\) ha\({}^{-1}\) year\({}^{-1}\)[127], and up to 100 Mg CO\({}_{2}\) ha\({}^{-1}\) year\({}^{-1}\)[128]. In their study, [PERSON] and [PERSON] (2018) [129] noted that, in the case of subtropical peatlands, the rate of peat settling amounting to 4.7 cm year\({}^{-1}\) generated up to 121 Mg CO\({}_{2}\) ha\({}^{-1}\) year\({}^{-1}\). Hence, it seems that using remote sensing to gather repeated measurements of peatlands elevation [38; 39; 72; 75] may be a viable method for observing the degradation of these environments and, by extension, the monitoring of potential hazards related to the emission of greenhouse gasses from peatlands into the atmosphere. [PERSON] et al. (2019) [2] noted that the current global knowledge and mapping of peatlands is poor. Peatlands are fragmented, occupying a relatively small area (around 3% worldwide), and are often overlooked by large-scale soil surveys. This means that the results obtained using RS methods can be important in studying climate and GHG emissions. In the past, the basic methods for delimitating the spatial distribution of peatlands and temporal changes in the surface features of peatlands included analysing topographic maps.