Results of the sensitivity analysis for nine key parameters used to model emissions from the land-use sector of Panama with the matrix model (Bucki et al 2012)
Figure 2. Results of the sensitivity analysis for nine key parameters used to model emissions from the land-use sector of Panama with the matrix model (Bucki et al 2012). Modelled annual CO2 emissions from the land-use sector (blue) and the difference with the reference emission level (REL) (red curve and %). Positive values for annual emissions indicate the sector is a source of CO2 and negative values a sink. Abbreviations: IFL and NIFL Stock: intact and non-intact forest carbon stock; IFL and NIFL Inc: intact and non-intact forest carbon increment; 'OL → IFL = 0': assumption that the entire reforested area resulting from the land-use change 'from other land to intact forest' should automatically be reclassified as non-intact forest for a duration ensuring that the forest recover its properties. 0 = assumption rejected, 1 = accepted; Edge: width of the buffer area surrounding intact forests along road, rivers, infrastructure and agriculture plots; 'Fallows=Forests': assumption that fallows are accounted as forests. 0: fallows = other land, 1: fallows = forests; Time interval: time between the two land-use maps; Map resolution: map pixel size.
The United Nations Framework Convention on Climate Change (UNFCCC) defined the technical and financial modalities of policy approaches and incentives to reduce emissions from deforestation and forest degradation in developing countries (REDD+). Substantial technical challenges hinder precise and accurate estimation of forest-related emissions and removals, as well as the setting and assessment of reference levels. These challenges could limit country participation in REDD+, especially if REDD+ emission reductions were to meet quality standards required to serve as compliance grade offsets for developed countries' emissions. Using Panama as a case study, we tested the matrix approach proposed by Bucki et al (2012 Environ. Res. Lett. 7 024005) to perform sensitivity and uncertainty analysis distinguishing between 'modelling sources' of uncertainty, which refers to model-specific parameters and assumptions, and 'recurring sources' of uncertainty, which refers to random and systematic errors in emission factors and activity data. The sensitivity analysis estimated differences in the resulting fluxes ranging from 4.2% to 262.2% of the reference emission level. The classification of fallows and the carbon stock increment or carbon accumulation of intact forest lands were the two key parameters showing the largest sensitivity. The highest error propagated using Monte Carlo simulations was caused by modelling sources of uncertainty, which calls for special attention to ensure consistency in REDD+ reporting which is essential for securing environmental integrity. Due to the role of these modelling sources of uncertainty, the adoption of strict rules for estimation and reporting would favour comparability of emission reductions between countries. We believe that a reduction of the bias in emission factors will arise, among other things, from a globally concerted effort to improve allometric equations for tropical forests. Public access to datasets and methodology used to evaluate reference level and emission reductions would strengthen the credibility of the system by promoting accountability and transparency. To secure conservativeness and deal with uncertainty, we consider the need for further research using real data available to developing countries to test the applicability of conservative discounts including the trend uncertainty and other possible options that would allow real incentives and stimulate improvements over time. Finally, we argue that REDD+ result-based actions assessed on the basis of a dashboard of performance indicators, not only in 'tonnes CO2 equ. per year' might provide a more holistic approach, at least until better accuracy and certainty of forest carbon stocks emission and removal estimates to support a REDD+ policy can be reached.