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The global climate warming caused by greenhouse gases poses a great threat to human living and biological ecosystems. To mitigate climate change, many measures have been taken to reduce carbon dioxide emissions. Among them, the forest carbon sink (FCS) is considered as one of the most economical and effective carbon sequestration methods to realize carbon emission reductions in next 30 to 50 years. FCS projects are being implemented in many countries to increase their carbon sequestration and thereby to realize carbon emission reductions. However, there are some issues associated with implementation with such policies. Firstly, these projects mainly have focused only on carbon sequestration and have ignored the comprehensive ecological effects to obtain their best economical benefits. Secondly, implementing these projects fails to establish a sustainable and healthy forest industry because they place too much reliance on preferential policies from governments. Finally, the projects lack systematic technological standards and legislation to guarantee their smooth implementation. This editorial briefly discusses these issues for the suitable implementation of the FCS projects. [ABSTRACT FROM AUTHOR]

Climate change mitigation requires, besides reductions in greenhouse gas emissions, actions to increase carbon sinks in terrestrial ecosystems. A key measurement method for quantifying such sinks and calibrating models is the eddy covariance technique, but it requires imputation, or gap-filling, of missing data for determination of annual carbon balances of ecosystems. Previous comparisons of gap-filling methods have concluded that commonly used methods, such as marginal distribution sampling (MDS), do not have a significant impact on the carbon balance estimate. By analyzing an extensive, global data set, we show that MDS causes significant carbon balance errors for northern (latitude > 60 ∘ ) sites. MDS systematically overestimates the carbon dioxide (CO 2 ) emissions of carbon sources and underestimates the CO 2 sequestration of carbon sinks. We also reveal reasons for these biases and show how a machine learning method called extreme gradient boosting or a modified implementation of MDS can be used to substantially reduce the northern site bias. [ABSTRACT FROM AUTHOR]

Mangrove forests are important carbon sinks, and this is especially true for Indonesia where about 24% of the world's mangroves exist. Unfortunately, vast expanses of these mangroves have been deforested, degraded or converted to other uses resulting in significant greenhouse gas emissions. The objective of this study was to quantify the climate change mitigation potential of mangrove conservation and restoration in Indonesia. We calculated the emission factors from the dominant land uses in mangroves, determined mangrove deforestation rates and quantified the total emissions and the potential emission reductions that could be achieved from mangrove conservation and restoration. Based on our analysis of the carbon stocks and emissions from land use in mangroves we found: (1) Indonesia's mangrove ecosystem carbon stocks are among the highest of any tropical forest type; (2) mangrove deforestation results in greenhouse gas emissions that far exceed that of upland tropical deforestation; (3) in the last decade the rates of deforestation in Indonesian mangroves have remained high; and (4) conservation and restoration of mangroves promise to sequester significant quantities of carbon. While mangroves comprise only ≈2.6% of Indonesia's total forest area, their degradation and deforestation accounted for ≈10% of total greenhouse gas emissions arising from the forestry sector. The large source of greenhouse gas emissions from a relatively small proportion of the forest area underscores the value for inclusion of mangroves as a natural climate solution. Mangrove conservation is far more effective than mangrove restoration in carbon emissions reductions and an efficient pathway to achieve Indonesia's nationally determined contribution (NDC) targets. The potential emission reduction from halting deforestation of primary and secondary mangroves coupled with restoration activities could result in an emission reduction equivalent to 8% of Indonesia's 2030 NDC emission reduction targets from the forestry sector. [ABSTRACT FROM AUTHOR]

The forest sector can play a significant role in climate change mitigation. We evaluated forest sector carbon trends and potential mitigation scenarios in Vermont using a systems‐based modeling framework that accounts for net emissions from all forest sector components. These components comprise (1) the forest ecosystem, including land‐use change, (2) harvested wood products (HWP), and (3) substitution effects associated with using renewable wood‐based products and fuels in place of more emission‐intensive materials and fossil fuel‐based energy. We assessed baseline carbon trends from 1995 through 2050 using a business as usual (BAU) scenario. Emission reductions associated with different forest management and HWP scenarios were evaluated relative to the BAU scenario from 2020 to 2050. We estimated uncertainty for each forest sector component and used a Monte Carlo approach to estimate the distribution of cumulative total mitigation for each scenario relative to baseline. Our analysis indicates that the strength of the forest sector carbon sink in Vermont has been declining and will continue to decline over coming decades under the BAU scenario. However, several scenarios evaluated here could be effective in reducing emissions and enhancing carbon uptake. Shifting HWP to longer‐lived commodities resulted in a 14% reduction in net cumulative emissions by 2050, the largest reduction of all scenarios. A scenario that combined extending harvest rotations, utilizing additional harvest residues for bioenergy, and increasing forest productivity resulted in a 12% reduction in net cumulative emissions. Shifting commodities from pulp and paper to bioenergy showed a 7.3% reduction in emissions. In contrast, shortening rotations to increase harvests for bioenergy use resulted in a 5.5% increase in emissions. In summary, model simulations suggest that net emissions could be reduced by up to 14% relative to BAU, depending on the management and HWP‐use scenario. Combining multiple scenarios could further enhance reductions. However, realizing the full climate mitigation potential of these forests may be challenging due to socioeconomic barriers to implementation, as well as alternative management objectives that must be considered along with carbon sequestration. [ABSTRACT FROM AUTHOR]

Scenarios avoiding global warming greater than 1.5 or 2 ∘ C, as stipulated in the Paris Agreement, may require the combined mitigation of anthropogenic greenhouse gas emissions alongside enhancing negative emissions through approaches such as afforestation–reforestation (AR) and biomass energy with carbon capture and storage (BECCS). We use the JULES land surface model coupled to an inverted form of the IMOGEN climate emulator to investigate mitigation scenarios that achieve the 1.5 or 2 ∘ C warming targets of the Paris Agreement. Specifically, within this IMOGEN-JULES framework, we focus on and characterise the global and regional effectiveness of land-based (BECCS and/or AR) and anthropogenic methane (CH4) emission mitigation, separately and in combination, on the anthropogenic fossil fuel carbon dioxide (CO2) emission budgets (AFFEBs) to 2100. We use consistent data and socio-economic assumptions from the IMAGE integrated assessment model for the second Shared Socioeconomic Pathway (SSP2). The analysis includes the effects of the methane and carbon–climate feedbacks from wetlands and permafrost thaw, which we have shown previously to be significant constraints on the AFFEBs. Globally, mitigation of anthropogenic CH4 emissions has large impacts on the anthropogenic fossil fuel emission budgets, potentially offsetting (i.e. allowing extra) carbon dioxide emissions of 188–212 Gt C. This is because of (a) the reduction in the direct and indirect radiative forcing of methane in response to the lower emissions and hence atmospheric concentration of methane and (b) carbon-cycle changes leading to increased uptake by the land and ocean by CO2 -based fertilisation. Methane mitigation is beneficial everywhere, particularly for the major CH4 -emitting regions of India, the USA, and China. Land-based mitigation has the potential to offset 51–100 Gt C globally, the large range reflecting assumptions and uncertainties associated with BECCS. The ranges for CH4 reduction and BECCS implementation are valid for both the 1.5 and 2 ∘ C warming targets. That is the mitigation potential of the CH4 and of the land-based scenarios is similar for regardless of which of the final stabilised warming levels society aims for. Further, both the effectiveness and the preferred land management strategy (i.e. AR or BECCS) have strong regional dependencies. Additional analysis shows extensive BECCS could adversely affect water security for several regions. Although the primary requirement remains mitigation of fossil fuel emissions, our results highlight the potential for the mitigation of CH4 emissions to make the Paris climate targets more achievable. [ABSTRACT FROM AUTHOR]

Transferring carbon from the atmosphere into terrestrial sinks through carbon sequestration practices (so-called ‘carbon farming’) has been proposed as an important component in Australia’s efforts to mitigate greenhouse gas emissions. We use a Best–worst scaling survey to determine which carbon sequestration practices farmers would be most and least likely to adopt, and what factors were most important in any potential adoption decision. The survey was distributed to dryland cropping and mixed crop-livestock farmers in Western Australia. Farmers ranked improved soil quality and reduced soil erosion as the most important potential co-benefits of carbon farming. Factors discouraging farmers from participating in carbon farming contracts were policy and carbon price uncertainty and the uncertain impact of carbon farming practices on productivity and profitability. Farmers had strong preferences for stubble retention and no-till cropping practices as carbon farming strategies. The practices that farmers preferred least were applying biochar and planting trees. Farm and farmer characteristics, including (lack of) awareness of carbon farming policies and opinions about climate change, influence the potential willingness to adopt different carbon farming practices. Given recent policy uncertainty and farmer preferences revealed in this study, it is important to communicate potential co-benefits (rather than opportunities to earn compensation or carbon credits) to increase farmers’ engagement in carbon sequestration activities. [ABSTRACT FROM AUTHOR]