Burning of fossil fuels and land – use change, particularly deforestation, have resulted in a steady accumulation of CO 2 and other greenhouse gases in the atmosphere, which is the cause of global warming (IPCC, 2003) . The two major strategies to mitigate the potential negative effects of climate chang e are reducing the emission of greenhouse gases and the capture and storage of CO 2 from the atmosphere. Through the framework of the Clean Development Mechanism (CDM) under the Kyoto protocol, increasing terrestrial sinks through afforestation and reforest ation are the two accredited activities. Besides afforestation and reforestation, reducing Emissions from Deforestation and Forest Degradation (REDD) and enhancing carbon stocks thought sustainable land management (REDD+) are given due credit in mitigating climate change (Campbell, 2009) .
Tag: carbon sinks
Mapping of soil organic carbon stocks for spatially explicit assessments of climate change mitigation potential
Current methods for assessing soil organic carbon (SOC) stocks are generally not well suited for understanding variations in SOC stocks in landscapes. This is due to the tedious and time-consuming nature of the sampling methods most commonly used to collect bulk density cores, which limits repeatability across large areas, particularly where information is needed on the spatial dynamics of SOC stocks at scales relevant to management and for spatially explicit targeting of climate change mitigation options. In the current study, approaches were explored for (i) field-based estimates of SOC stocks and (ii) mapping of SOC stocks at moderate to high resolution on the basis of data from four widely contrasting ecosystems in East Africa. Estimated SOC stocks for 0–30 cm depth varied both within and between sites, with site averages ranging from 2 to 8 kg m2. The differences in SOC stocks were determined in part by rainfall, but more importantly by sand content. Results also indicate that managing soil erosion is a key strategy for reducing SOC loss and hence in mitigation of climate change in these landscapes. Further, maps were developed on the basis of satellite image reflectance data with multiple R-squared values of 0.65 for the independent validation data set, showing variations in SOC stocks across these landscapes. These maps allow for spatially explicit targeting of potential climate change mitigation efforts through soil carbon sequestration, which is one option for climate change mitigation and adaptation. Further, the maps can be used to monitor the impacts of such mitigation efforts over time.
Modeling the Impact of Canal Blocking on Water Table Dynamics and Carbon Emissions in Drained Peatlands
Peatlands are significant carbon sinks, storing vast amounts of organic carbon in their waterlogged soils However, when they are drained for agricultural or other land-use purposes, the natural hydrological balance is disrupted. This disruption allows the soil organic carbon to decompose, leading to peat subsidence and the release of carbon emissions into the atmosphere and waterways. Extensive drainage systems exacerbate this process, transforming peatlands from globally significant carbon sinks into one of the leading contributors of greenhouse gas emissions from the landbased sector.
Trees on smallholder farms and forest restoration are critical for Rwanda to achieve net zero emissions
Landscape restoration initiatives are mainly focusing on forest regeneration and agroforestry, especially in the Global South. However, due to a lack of monitoring tools, the carbon balance of restoration efforts remains poorly quantified. Here, we use satellite images from 2008 and 2019 to calculate carbon stocks for individual trees in Rwanda, a country which has been actively engaged in restoration activities over the past decade. We show that smallholder farmers on average planted about 3 trees per farm during 2008–2019, contributing about 50.4 million new trees at the national scale. The overall C sink of the new farmland trees was 0.13 Megagrams of Carbon per hectare per year, which is 6 times lower than gains observed from restoration of degraded forests (0.76 Megagrams of Carbon per hectare per year). If national greenhouse gas emissions remain at the level of 2019, agroforestry (~61% of national area coverage) and continued restoration of degraded natural forests (~0.5% of national area coverage) have the potential to offset about 80% of the national emissions before 2050. Our work monitors and quantifies progress and impact of landscape restoration projects and outlines a pathway to engage smallholder farmers with a limited number of on-farm trees into the expanding carbon market.
Effect of elevation and aspect on carbon stock of bamboo stands (Bambusa nutans subsp. Cupulata) outside the forest area in Eastern Nepal
Bamboo has emerged as a promising option for climate change mitigation due to its rapid growth, versatility, and renewability. However, in Nepal, there exists a substantial knowledge gap on carbon (C) stock and the influence of aspect and elevation on C stock of bamboo species, particularly in areas outside forests where bamboo is dominant. Therefore, this research was conducted to quantify C stock and aspect-elevation influence on the C stock of Bambusa nutans subsp. cupulata outside the forest area. For this study, three elevation zones (0–400 m, 400–800 m, 800–1200 m) and two aspects (East and West) were considered. A total of 30 square plots having a 100 m2 area were established utilizing purposive sampling due to the scattered distribution of bamboo. Non-destructive methods were applied to measure bamboo culm diameters, while composite soil samples were systematically collected from 30 cm depth using soil augers and core samplers. Clump density (400 ha⁻¹), culm density (42,480 ha⁻¹) and culm diameter (6.82 ± 0.41 cm) were highest at middle elevations (p 0.05). The total mean C stock potential of B. nutans was 148.73 ± 3.43 Mg ha⁻¹. Our results indicated a significant difference in C stock among elevation zones, with middle elevation zones (161.77 ± 6.74 Mg ha-1) exhibiting notably higher C stock compared to both lower (150.26 ± 2.69 Mg ha-1) and higher (134.17 ± 4.26 Mg ha-1) elevation zones. Furthermore, East aspect was found to have significantly (p < 0.05) higher soil organic C stock (18.52 ± 1.32 Mg ha-1) compared to West aspect (11.4 ± 1.01 Mg ha-1). Further research is needed to explore other complex environmental interactions with C stock potential for better climate change strategies. Incorporating bamboo C into Nepal's REDD+ initiative can be crucial for optimizing opportunities to earn C credits.
Central African biomass carbon losses and gains during 2010–2019
Disturbance, vegetation productivity, and recovery are crucial for aboveground biomass carbon (AGC) dynamics. Here, we use multiple satellite-based datasets to analyze the drivers of AGC dynamics in Central Africa. During 2010–2019, deforestation induced a gross AGC loss of 102.2 ± 17.1 Tg C year−1, which was counterbalanced by an AGC increase of 116.9 ± 41.1 Tg C year−1, leading to a net gain of 14.6 ± 3.8 Tg C year−1. Compared to anthropogenic and soil factors, changes in climate-related factors (e.g., radiation) are more important for the non-deforestation AGC changes. A large AGC increase was found in the northern savannas. In moist forests, strong biomass recovery and growth largely compensated the carbon loss from deforestation and degradation. Considering the increasing resource demand due to rapid population growth, reconciling natural conservation and economic development in Central Africa remains challenging and depends on climate changes and country-specific social-economic conditions.
Aligning international financial flows and the COMIFAC Convergence Plan
Central African forests, including those in the Congo Basin, play an essential role at the global level. They help to regulate the global climate, in part through the exchange of gases, which has led to them being designated the planet’s ‘second tropical forest lung’. The carbon stock held in their biomass and peatlands is estimated at 80 billion tons, equivalent to almost 10 years of global carbon dioxide emissions. Central Africa’s undisturbed forests now sequester more carbon than those in the Amazon (Dalimier et al. unpublished) and South-East Asia, and currently constitute the world’s largest tropical carbon sink. According to recent estimates by Global Forest Watch (GFW) researchers, forests in the Congo Basin sequester 600 million tons of CO2 more than they emit annually. On average, these forests emit 530 million tons of carbon each year – a figure that has remained stable – and remove 1.1 billion tons.
Regional Assessment for Latin America and the Caribbean
Regional Assessment for Asia
Analysis of the Ricinodendron heudelotii × Theobroma cacao L. Interaction in Traditional Agroforestry Systems in Côte d’Ivoire
The objective of this study was to improve cacao (Theobroma cacao) production through its association with a woody species, such as Ricinodendron heudelotii, in western Côte d’Ivoire. To do this, a design of two transects (10 m and 20 m) was installed around the species in 5 localities (Buyo, Duekoué, Guéyo, San-Pedro, and Soubré). The diameter at the breast height of the tree, the height, the number of fruits, the above biomass, and its carbon stock were measured. Results showed morphological variability of R. heudelotii according to the localities. The presence of the species within cacao trees reduces the rate of pod rot, stabilizes the rate of pods eaten away, and increases the biomass production and the carbon storage of cacao trees. The distance between the two species had no impact on the vigor and the yield of cacao trees. However, cacao density in the 10 m line was reduced compared to that of the 20 m. Therefore, the integration of R. heudelotii into cacao agroforestry systems could improve cacao production. That is why the reduction of cacao density, as well as the use of more suitable varieties of cacao, should be considered for the sustainability of this system.