The Variability of Air-sea O2 Flux in CMIP6: Implications for Estimating Terrestrial and Oceanic Carbon Sinks

The measurement of atmospheric O2 concentrations and related oxygen budget have been used to estimate terrestrial and oceanic carbon uptake. However, a discrepancy remains in assessments of O2 exchange between ocean and atmosphere (i.e. air-sea O2 flux), which is one of the major contributors to uncertainties in the O2-based estimations of the carbon uptake. Here, we explore the variability of air-sea O2 flux with the use of outputs from Coupled Model Intercomparison Project phase 6 (CMIP6). The simulated air-sea O2 flux exhibits an obvious warming-induced upward trend (∼1.49 Tmol yr−2) since the mid-1980s, accompanied by a strong decadal variability dominated by oceanic climate modes. We subsequently revise the O2-based carbon uptakes in response to this changing air-sea O2 flux. Our results show that, for the 1990–2000 period, the averaged net ocean and land sinks are 2.10±0.43 and 1.14±0.52 GtC yr−1 respectively, overall consistent with estimates derived by the Global Carbon Project (GCP). An enhanced carbon uptake is found in both land and ocean after year 2000, reflecting the modification of carbon cycle under human activities. Results derived from CMIP5 simulations also investigated in the study allow for comparisons from which we can see the vital importance of oxygen dataset on carbon uptake estimations.

Community, Forest Carbon & Indigeneity: A Case Study of the Loru Project in Espiritu Santo, Vanuatu

<p>Forest carbon farming offers customary landowners an alternative livelihood to socially and environmentally unsustainable logging, through the sale of carbon offset credits. REDD+, the global forest carbon scheme to address deforestation in developing countries, has attracted scholarly criticism for the risks it poses to communities. Critics warn that REDD+: (1) benefits may be captured by elites, (2) threatens forest-dependent livelihoods, (3) reduces local forest governance, and (4) a results-based payments mechanism can undermine conservation. Community-owned forest carbon farming may mitigate these risks by empowering communities to manage forest resources locally. The Loru project in Vanuatu is the first of its kind, and Indigenous landowners legally own the carbon rights and manage the carbon project. This thesis examines the community ownership and the social impact of the Loru project on its Indigenous project owners, the ni-Vanuatu Ser clan. The thesis uses a ‘semi’-mixed-methods approach, based primarily on interviews conducted in in Espiritu Santo, Vanuatu with Indigenous landowners and supplemented with quantitative data from a monitoring exercise conducted by the author. Grounded in social constructivism, the thesis makes a genuine attempt to decolonize the research process, adopting a self-reflexive approach. The research finds that the project is leading to positive social and economic impacts at the community level. Further, the Loru project is legitimately community-owned and driven, meaning it adapts effectively to the local context. Overall, the findings suggest that implementing REDD+ through a multi-scalar institutional network and building local capacity could mitigate the risks of REDD+ to forest communities.</p>

Community, Forest Carbon & Indigeneity: A Case Study of the Loru Project in Espiritu Santo, Vanuatu

<p>Forest carbon farming offers customary landowners an alternative livelihood to socially and environmentally unsustainable logging, through the sale of carbon offset credits. REDD+, the global forest carbon scheme to address deforestation in developing countries, has attracted scholarly criticism for the risks it poses to communities. Critics warn that REDD+: (1) benefits may be captured by elites, (2) threatens forest-dependent livelihoods, (3) reduces local forest governance, and (4) a results-based payments mechanism can undermine conservation. Community-owned forest carbon farming may mitigate these risks by empowering communities to manage forest resources locally. The Loru project in Vanuatu is the first of its kind, and Indigenous landowners legally own the carbon rights and manage the carbon project. This thesis examines the community ownership and the social impact of the Loru project on its Indigenous project owners, the ni-Vanuatu Ser clan. The thesis uses a ‘semi’-mixed-methods approach, based primarily on interviews conducted in in Espiritu Santo, Vanuatu with Indigenous landowners and supplemented with quantitative data from a monitoring exercise conducted by the author. Grounded in social constructivism, the thesis makes a genuine attempt to decolonize the research process, adopting a self-reflexive approach. The research finds that the project is leading to positive social and economic impacts at the community level. Further, the Loru project is legitimately community-owned and driven, meaning it adapts effectively to the local context. Overall, the findings suggest that implementing REDD+ through a multi-scalar institutional network and building local capacity could mitigate the risks of REDD+ to forest communities.</p>

Floristic, Structure, and Regeneration of Woody Species in Bola Wanche Forest of Humbo Carbon Project, Wolaita, Ethiopia

BackgroundThe forest resources of the Humbo Carbon Project have ecological and environmental problems such as soil degradation, soil erosion and alteration of natural resources are some of the negative effects resulting from the destruction of forests Our present study was carried out to investigate regeneration status and dynamics of populations of woody species in Bola Wanche forest of Humbo Carbon Project Wolaita zone, Ethiopia. Methods and ResultsThirty-two (20m x 20m) plots were laid at an interval of 100m to collect vegetation data. In each plot, five 1m 2 quadrats were laid to assess regeneration status. DBH (Diameter at Breast Height) of each woody species with DBH ≥2.5cm was measured. Altitude, aspect and slope of each plot were recorded. Among 61 woody species representing 56 genera and 35 families, Syzygium guineense and Dodonaea angustifolia were the most dominant. There was significant difference in the dominance (p < 0.0001) of species between plots. Inverted J-shape and bell-shape population distribution patterns were recognized. The regeneration phase was dominated by D. angustifolia. Only 36% of the species in matured vegetation was represented in seedling phase. Environmental factors considered in this study were not influenced abundance of species and individuals between plots. But when dominant species evaluated separately, altitude had significant influence on abundance of S. guineense and Combretum molle while aspect on C. molle and Terminalia schimperiana. But no factor had influenced abundance of D. angustifolia. ConclusionThe study concluded the abundance and dominance of few families and species, prevalence of small size populations and fair regeneration of forest. This may indicate that the forest is in its early secondary successional stage and need high intention of conservation and management.

Market Costs and Financing Options for Grassland Carbon Sequestration: Empirical and Modelling Evidence From Qinghai, China

Asia’s grasslands provide livelihoods for some of the region’s poorest people. Widespread grassland degradation reduces the resilience and returns to herding livelihoods. Reversing degradation and conserving grasslands could not only improve herders’ situation, but also make a huge contribution to mitigating climate change by sequestering carbon in soils. However, the means for reaching each of these objectives are not necessarily the same. To realize this potentially huge dual livelihood/climate change mitigation outcome from improved grassland management, it is necessary to have detailed understanding of the processes involved in securing better livelihoods and sequestering carbon. Based on household surveys on the Tibetan Plateau and modeling results, this study estimates economic and market costs of grassland carbon sequestration, and analyzes the implications of household and carbon project cash flows for the design of financing options. Five scenarios are modeled involving cultivation of grass on severely degraded grassland (all scenarios) and reduced grazing intensity on less degraded land, which requires destocking by 29, 38, 47, 56, and 65% in each scenario). Modeling results suggest that economic benefits for herders are positive at low levels of destocking, and negative at high levels of destocking, but initial investments and opportunity costs are significant barriers to adoption for households in all destocking scenarios. Existing rural finance products are not suitable for herders to finance the necessary investments. Market costs–the cost at which transactions between herders and carbon project developers are feasible–depend on the scale of project implementation but are high compared to recent carbon market prices. Large initial investments increase project developers’ financing costs and risk, so co-financing of initial investments by government would be necessary. Therefore, public policies to support grassland carbon sequestration should consider the potential roles of a range of financial instruments.

Gridded fossil CO2 emissions and related O2 combustion consistent with national inventories 1959–2018

Quantification of CO2 fluxes at the Earth’s surface is required to evaluate the causes and drivers of observed increases in atmospheric CO2 concentrations. Atmospheric inversion models disaggregate observed variations in atmospheric CO2 concentration to variability in CO2 emissions and sinks. They require prior constraints fossil CO2 emissions. Here we describe GCP-GridFED (version 2019.1), a gridded fossil emissions dataset that is consistent with the national CO2 emissions reported by the Global Carbon Project (GCP). GCP-GridFEDv2019.1 provides monthly fossil CO2 emissions estimates for the period 1959–2018 at a spatial resolution of 0.1°. Estimates are provided separately for oil, coal and natural gas, for mixed international bunker fuels, and for the calcination of limestone during cement production. GCP-GridFED also includes gridded estimates of O2 uptake based on oxidative ratios for oil, coal and natural gas. It will be updated annually and made available for atmospheric inversions contributing to GCP global carbon budget assessments, thus aligning the prior constraints on top-down fossil CO2 emissions with the bottom-up estimates compiled by the GCP.

PENGARUH GLOBALISASI KEPADATAN PENDUDUK DAN PERTUMBUHAN EKONOMI TERHADAP DEGRADASI LINGKUNGAN DI INDONESIA

: The study describes the effects on globalization population density andeconomic growth on environmental degradation in Indonesia. This research uses a timeseries data from year 1971 - 2017, with method Error Correction Model (ECM). Datasources from Global Carbon Project, KOF Swiss Economic Institute, and WorldBank. Research result explain that (1) Globalization in long term has a insignificantpositive effect on environmental degradation in Indonesia, but short term globalizationhas a insignificant negative effect on environmental degradation in Indonesia (2)Population density in long term has a significant positive , and short term has ainsignificant positive effect on environmental degradation in Indonesia (3) Economicgrowth in long and short term has a significant positive effect on environmentaldegradation in Indonesia.Keywords : Environmental Degradation, Globalization Population Density AndEconomic Growth.

Effects of Agroforestry and Other Sustainable Practices in the Kenya Agricultural Carbon Project (KACP)

With growing global demand for food, unsustainable farming practices and large greenhouse gas emissions, farming systems need to sequester more carbon than they emit, while also increasing productivity and food production. The Kenya Agricultural Carbon Project (KACP) recruited farmer groups committed to more Sustainable Agricultural Land Management (SALM) practices and provided these groups with initial advisory services on SALM, farm enterprise development and village savings and loan associations. Recommended SALM practices included agroforestry, cover crops, mulching, composting manure, terracing, reduced tillage and water harvesting. The effects of the KACP on the uptake of SALM practices, maize yield, perceived food self-sufficiency and savings during the initial four years were assessed comparing control and project farmers using interviews, field visits and measurements. Farmers participating in the KACP seemed to have increased uptake of most SALM practices and decreased the use of practices to be avoided under the KACP recommendations. Agroforestry and terraces showed positive effects on maize yield. During all four years, the KACP farms had higher maize yield than control farms, but yield differences were similar in 2009 and 2012 and there was no overall significant effect of the KACP. In 2012, the KACP farms had higher food self-sufficiency and tended to have higher monetary savings than control farms.

The Global Methane Budget 2000–2017

Understanding and quantifying the global methane (CH4) budget is important for assessing realistic pathways to mitigate climate change. Atmospheric emissions and concentrations of CH4 continue to increase, making CH4 the second most important human-influenced greenhouse gas in terms of climate forcing, after carbon dioxide (CO2). The relative importance of CH4 compared to CO2 depends on its shorter atmospheric lifetime, stronger warming potential, and variations in atmospheric growth rate over the past decade, the causes of which are still debated. Two major challenges in reducing uncertainties in the atmospheric growth rate arise from the variety of geographically overlapping CH4 sources and from the destruction of CH4 by short-lived hydroxyl radicals (OH). To address these challenges, we have established a consortium of multidisciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate new research aimed at improving and regularly updating the global methane budget. Following Saunois et al. (2016), we present here the second version of the living review paper dedicated to the decadal methane budget, integrating results of top-down studies (atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up estimates (including process-based models for estimating land surface emissions and atmospheric chemistry, inventories of anthropogenic emissions, and data-driven extrapolations). For the 2008–2017 decade, global methane emissions are estimated by atmospheric inversions (a top-down approach) to be 576 Tg CH4 yr−1 (range 550–594, corresponding to the minimum and maximum estimates of the model ensemble). Of this total, 359 Tg CH4 yr−1 or ∼ 60 % is attributed to anthropogenic sources, that is emissions caused by direct human activity (i.e. anthropogenic emissions; range 336–376 Tg CH4 yr−1 or 50 %–65 %). The mean annual total emission for the new decade (2008–2017) is 29 Tg CH4 yr−1 larger than our estimate for the previous decade (2000–2009), and 24 Tg CH4 yr−1 larger than the one reported in the previous budget for 2003–2012 (Saunois et al., 2016). Since 2012, global CH4 emissions have been tracking the warmest scenarios assessed by the Intergovernmental Panel on Climate Change. Bottom-up methods suggest almost 30 % larger global emissions (737 Tg CH4 yr−1, range 594–881) than top-down inversion methods. Indeed, bottom-up estimates for natural sources such as natural wetlands, other inland water systems, and geological sources are higher than top-down estimates. The atmospheric constraints on the top-down budget suggest that at least some of these bottom-up emissions are overestimated. The latitudinal distribution of atmospheric observation-based emissions indicates a predominance of tropical emissions (∼ 65 % of the global budget, < 30∘ N) compared to mid-latitudes (∼ 30 %, 30–60∘ N) and high northern latitudes (∼ 4 %, 60–90∘ N). The most important source of uncertainty in the methane budget is attributable to natural emissions, especially those from wetlands and other inland waters. Some of our global source estimates are smaller than those in previously published budgets (Saunois et al., 2016; Kirschke et al., 2013). In particular wetland emissions are about 35 Tg CH4 yr−1 lower due to improved partition wetlands and other inland waters. Emissions from geological sources and wild animals are also found to be smaller by 7 Tg CH4 yr−1 by 8 Tg CH4 yr−1, respectively. However, the overall discrepancy between bottom-up and top-down estimates has been reduced by only 5 % compared to Saunois et al. (2016), due to a higher estimate of emissions from inland waters, highlighting the need for more detailed research on emissions factors. Priorities for improving the methane budget include (i) a global, high-resolution map of water-saturated soils and inundated areas emitting methane based on a robust classification of different types of emitting habitats; (ii) further development of process-based models for inland-water emissions; (iii) intensification of methane observations at local scales (e.g., FLUXNET-CH4 measurements) and urban-scale monitoring to constrain bottom-up land surface models, and at regional scales (surface networks and satellites) to constrain atmospheric inversions; (iv) improvements of transport models and the representation of photochemical sinks in top-down inversions; and (v) development of a 3D variational inversion system using isotopic and/or co-emitted species such as ethane to improve source partitioning. The data presented here can be downloaded from https://doi.org/10.18160/GCP-CH4-2019 (Saunois et al., 2020) and from the Global Carbon Project.