Modelling the effects of climate and management on the distribution of deadwood in European forests.

Deadwood is a key old-growth element in European forests and a cornerstone of biodiversity conservation practices in the region, recognized as an important indicator of sustainable forest management. Despite its importance as a legacy element for biodiversity, uncertainties remain on the drivers of deadwood potentials, its spatial distribution in European forests and how it may change in the future due to management and climate change. To fill this gap, we combined a comprehensive deadwood dataset to fit a machine learning and a Bayesian hurdle-lognormal model against multiple environmental and socio-economic predictors. We deployed the models on the gridded predictors to forecast changes in deadwood volumes in Europe under alternative climate (RCP4.5 and RCP8.5) and management scenarios (biodiversity-oriented and production-oriented strategies). Our results show deadwood hotspots in montane forests of central Europe and unmanaged forests in Scandinavia. Future climate conditions may reduce deadwood potentials up to 13% under a mid-century climate, with regional losses amounting to up to 22% in Southern Europe. Nevertheless, changes in management towards more biodiversity-oriented strategies, including an increase in the share of mixed forests and extended rotation lengths, may mitigate this loss to a 4% reduction in deadwood potentials. We conclude that adaptive management can promote deadwood under changing environmental conditions and thereby support habitat maintenance and forest multifunctionality.

Enhanced agricultural carbon sinks provide benefits for farmers and the climate.

Carbon sequestration on agricultural land, albeit long-time neglected, offers substantial mitigation potential. Here we project, using an economic land-use model, that these options offer cumulative mitigation potentials comparable to afforestation by 2050 at 160 USD2022 tCO2 equivalent (tCO2e-1), with most of it located in the Global South. Carbon sequestration on agricultural land could provide producers around the world with additional revenues of up to 375 billion USD2022 at 160 USD2022 tCO2e-1 and allow achievement of net-zero emissions in the agriculture, forestry and other land-use sectors by 2050 already at economic costs of around 80-120 USD2022 tCO2e-1. This would, in turn, decrease economy-wide mitigation costs and increase gross domestic product (+0.6%) by the mid-century in 1.5 °C no-overshoot climate stabilization scenarios compared with mitigation scenarios that do not consider these options. Unlocking these potentials requires the deployment of highly efficient institutions and monitoring systems over the next 5 years across the whole world, including sub-Saharan Africa, where the largest mitigation potential exists.

Impact of modelling choices on setting the reference levels for the EU forest carbon sinks: how do different assumptions affect the country-specific forest reference levels?

BACKGROUND: In 2018, the European Union (EU) adopted Regulation 2018/841, which sets the accounting rules for the land use, land use change and forestry (LULUCF) sector for the period 2021-2030. This regulation is part of the EU's commitments to comply with the Paris Agreement. According to the new regulation, emissions and removals for managed forest land are to be accounted against a projected forest reference level (FRL) that is estimated by each EU Member State based on the continuation of forest management practices of the reference period 2000-2009. The aim of this study is to assess how different modelling assumptions possible under the regulation may influence the FRL estimates. Applying the interlinked G4M and WoodCarbonMonitor modelling frameworks, we estimate potential FRLs for each individual EU Member State following a set of conceptual scenarios, each reflecting different modelling assumptions that are consistent with the regulation and the technical guidance document published by the European Commission. RESULTS: The simulations of the conceptual scenarios show that differences in the underlying modelling assumptions may have a large impact on the projected FRL. Depending on the assumptions taken, the projected annual carbon sink on managed forest land in the EU varies from -319 MtCO2 to -397 MtCO2 during the first compliance period (2021-2025) and from -296 MtCO2 to -376 MtCO2 during the second compliance period (i.e. 2026-2030). These estimates can be compared with the 2017 national GHG inventories which estimated that the forest carbon sink for managed forest land was -373 MtCO2 in 2015. On an aggregated EU level, the assumptions related to climate change and the allocation of forest management practices have the largest impacts on the FRL estimates. On the other hand, assumptions concerning the starting year of the projection, stratification of managed forest land, and timing of individual management activities are found to have relatively small impacts on the FRL estimates. CONCLUSIONS: We provide a first assessment of the level of uncertainty associated with the different assumptions discussed in the technical guidance document and the LULUCF regulation, and the impact of these assumptions on the country-specific FRL. The results highlight the importance of transparent documentation by the EU Member States on how their FRL has been calculated, and on the underlying assumptions.

Assessing the INDCs' land use, land use change, and forest emission projections.

BACKGROUND: In preparation for the 2015 international climate negotiations in Paris, Parties submitted Intended Nationally Determined Contributions (INDCs) to the United Nations Framework Convention on Climate Change (UNFCCC) expressing each countries' respective post-2020 climate actions. In this paper we assess individual Parties' expected reduction of emissions/removals from land use, land use change, and forest (LULUCF) sector for reaching their INDC target, and the aggregate global effect on the INDCs on the future development of emission and removals from the LULUCF sector. This has been done through analysis Parties' official information concerning the role of LULUCF mitigation efforts for reaching INDC targets as presented in National Communications, Biennial Update Reports, and Additional file 1. RESULTS: On the aggregate global level, the Parties themselves perceive that net LULUCF emissions will increase over time. Overall, the net LULUCF emissions are estimated to increase by 0.6 Gt CO2e year-1 (range: 0.1-1.1) in 2020 and 1.3 Gt CO2e year-1 (range: 0.7-2.1) in 2030, both compared to 2010 levels. On the other hand, the full implementation of the INDCs is estimated to lead to a reduction of net LULUCF emissions in 2030 compared to 2010 levels. It is estimated that if all conditional and unconditional INDCs are implemented, net LULUCF emissions would decrease by 0.5 Gt CO2e year-1 (range: 0.2-0.8) by 2020 and 0.9 Gt CO2e year-1 (range: 0.5-1.3) by 2030, both compared to 2010 levels. The largest absolute reductions of net LULUCF emissions (compared to 2010 levels) are expected from Indonesia and Brazil, followed by China and Ethiopia. CONCLUSIONS: The results highlights that countries are expecting a significant contribution from the LULUCF sector to meet their INDC mitigation targets. At the global level, the LULUCF sector is expected to contribute to as much as 20% of the full mitigation potential of all the conditional and unconditional INDC targets. However, large uncertainties still surround how Parties estimate, project and account for emissions and removals from the LULUCF sector. While INDCs represent a new source of land-use information, further information and updates of the INDCs will be required to reduce uncertainty of the LULUCF projections.

On fair, effective and efficient REDD mechanism design.

The issues surrounding 'Reduced Emissions from Deforestation and Forest Degradation' (REDD) have become a major component of continuing negotiations under the United Nations Framework Convention on Climate Change (UNFCCC). This paper aims to address two key requirements of any potential REDD mechanism: first, the generation of measurable, reportable and verifiable (MRV) REDD credits; and secondly, the sustainable and efficient provision of emission reductions under a robust financing regime.To ensure the supply of MRV credits, we advocate the establishment of an 'International Emission Reference Scenario Coordination Centre' (IERSCC). The IERSCC would act as a global clearing house for harmonized data to be used in implementing reference level methodologies. It would be tasked with the collection, reporting and subsequent processing of earth observation, deforestation- and degradation driver information in a globally consistent manner. The IERSCC would also assist, coordinate and supervise the computation of national reference scenarios according to rules negotiated under the UNFCCC. To overcome the threats of "market flooding" on the one hand and insufficient economic incentives for REDD on the other hand, we suggest an 'International Investment Reserve' (IIR) as REDD financing framework. In order to distribute the resources of the IIR we propose adopting an auctioning mechanism. Auctioning not only reveals the true emission reduction costs, but might also allow for incentivizing the protection of biodiversity and socio-economic values. The introduced concepts will be vital to ensure robustness, environmental integrity and economic efficiency of the future REDD mechanism.