Cross-scale drivers of greenhouse gas emissions and local solutions for climate change mitigation

Um das 1,5°C Ziel zu verhindern, müssen bis 2020 die globalen anthropogenen CO2 Emissionen Sektor-übergreifend ihren Spitzenwert erreichen und bis 2050 auf Netto-Null-Emissionen sinken. Der AFOLU Sektor hat einen Anteil von 23% an den globalen Treibhausgasemissionen (THGE). Neben der Möglichkeit THGE zu vermeiden, bietet die Implementierung von Klimaschutzmitigation auch Synergien um die Ernährungssicherheit, Nährstoff- und Wassereffizienz zu verbessern sowie Landdegradation umzukehren. Eine kritische Bedeutung hat die Abholzung von tropischen Waldflächen durch die mehr als ein Drittel der Emissionen im Bereich des AFOLU entsteht. Vor diesem Hintergrund werden vorliegend, mit Fokus auf die Abholzung in der tropischen Zone, die indirekten Auslöser der THGE innerhalb des AFOLU untersucht. Diese Auslöser werden zunächst auf einer globalen Skala analysiert, wobei die Rolle der Variabilität von Preisveränderungen international gehandelter Waren und weiterer sozio-ökonomischer Indikatoren auf regionale Waldumwandlungsprozesse betrachtet wird. Anschließend analysiert diese Arbeit den Aspekt des Waldverlustes im Zusammenhang mit politischer Instabilität und bewaffneten Konflikten. Zudem werden regionale Lösungen zur Mitigation in weiteren Sektoren adressiert. Insbesondere wird die Möglichkeit zur THGE-Einsparung in silvopastoralen Systemen untersucht um das Zusammenspiel zwischen intensiver Viehbewirtschaftung und der Kohlenstofffixierung besser zu verstehen. Darüber hinaus werden regionale Lösungen mit Hilfe von Basisorganisationen bzw. gemeindebasierten Initiativen (CBI) zur THGE-Einsparung in den Bereichen Energie, Nahrungsmittel, Transport und Abfall erforscht. Diese Arbeit liefert vielfältige Beiträge zum Verständnis der indirekten Auslöser von Abholzung und den damit verbundenen THGE innerhalb der tropischen Zone, sowie zur Förderung lokaler Lösungen für die sektorübergreifende THG-Minderung.Global anthropogenic CO2 emissions from different sectors must peak in 2020 and reach net zero by 2050 in order to reach the 1.5°C target. The AFOLU sector represents 23% of global greenhouse gas (GHG) emissions. In addition to its mitigation potential, the implementation of solutions in this sector also holds the synergistic potential of enhancing climate change adaptation, improving food security, nutrient and water efficiency, and reverting land degradation. Tropical deforestation is of particular importance within the AFOLU sector, representing over a third of its emissions. Against this backdrop, this thesis examines the underlying drivers of GHG emissions in the AFOLU sector, with a particular emphasis on tropical deforestation. These drivers are explored, firstly, at a global scale by addressing the role that changes in price of internationally-traded commodity products and other socio-economic variables exert on regional forest conversion. Secondly, this work examines the relationship between tree cover loss and a very under-researched driver of tropical deforestation, namely extreme political instability and armed conflict. Motivated by the urgency of climate change impacts, this thesis also explores local solutions for climate change mitigation across different sectors. In particular, the GHG mitigation role of silvopastoral systems, a type of agroforestry system, is examined to further understand the interplay between livestock intensification and carbon sequestration. In addition, more broad, local-scale solutions are examined across the energy, food, transport, and waste sectors by addressing the GHG mitigation potential of grassroots organizations, also known as community-based initiatives (CBIs). This thesis provides manifold contributions, not only to further understand some of the underlying drivers of deforestation and associated GHG emissions in the tropics, but also towards the advancement of local solutions for GHG mitigation across sectors

Reducing deforestation and improving livestock productivity: greenhouse gas mitigation potential of silvopastoral systems in Caquetá

Colombia's agriculture, forestry and other land use sector accounts for nearly half of its total greenhouse gas (GHG) emissions. The importance of smallholder deforestation is comparatively high in relation to its regional counterparts, and livestock agriculture represents the largest driver of primary forest depletion. Silvopastoral systems (SPSs) are presented as agroecological solutions that synergistically enhance livestock productivity, improve local farmers' livelihoods and hold the potential to reduce pressure on forest conversion. The department of Caquetá represents Colombia's most important deforestation hotspot. Targeting smallholder livestock farms through survey data, in this work we investigate the GHG mitigation potential of implementing SPSs for smallholder farms in this region. Specifically, we assess whether the carbon sequestration taking place in the soil and biomass of SPSs is sufficient to offset the per-hectare increase in livestock GHG emissions resulting from higher stocking rates. To address these questions we use data on livestock population characteristics and historic land cover changes reported from a survey covering 158 farms and model the carbon sequestration occurring in three different scenarios of progressively-increased SPS complexity using the CO2 fix model. We find that, even with moderate tree planting densities, the implementation of SPSs can reduce GHG emissions by 2.6 Mg CO2e ha−1 yr−1 in relation to current practices, while increasing agriculture productivity and contributing to the restoration of severely degraded landscapes

Land-based measures to mitigate climate change : potential and feasibility by country

Acknowledgements The design of this study and the data generated was guided by expert consultations and relied on the help of many. We thank all those who contributed: Sierra Gladfelter, Jo House, Mercedes Bustamante, Susan Cook-Patton, Sara Leavitt, Nick Wolff, and Thomas Worthington. We thank M.-J. Valentino at Imaginary Office for helping to design the first three figures. This work was supported by the authors’ institutions and funding sources, including the Climate and Land-use Alliance, the Dutch Ministry of Agriculture, Nature Management and Food Quality, and the EU H2020 projects VERIFY and ENGAGE (grant agreement no. 821471).Peer reviewedPublisher PD

Reducing deforestation and improving livestock productivity: greenhouse gas mitigation potential of silvopastoral systems in Caquetá.

Colombiaʼs agriculture, forestry and other land use sector accounts for nearly half of its total greenhouse gas (GHG) emissions. The importance of smallholder deforestation is comparatively high in relation to its regional counterparts, and livestock agriculture represents the largest driver of primary forest depletion. Silvopastoral systems (SPSs) are presented as agroecological solutions that synergistically enhance livestock productivity, improve local farmers’ livelihoods and hold the potential to reduce pressure on forest conversion. The department of Caquetá represents Colombia’s most important deforestation hotspot. Targeting smallholder livestock farms through survey data, in this work we investigate theGHGmitigation potential of implementing SPSs for smallholder farms in this region. Specifically, we assess whether the carbon sequestration taking place in the soil and biomass of SPSs is sufficient to offset the per-hectare increase in livestockGHGemissions resulting from higher stocking rates. To address these questions we use data on livestock population characteristics and historic land cover changes reported from a survey covering 158 farms and model the carbon sequestration occurring in three different scenarios of progressively-increased SPS complexity using theCO2 fix model.Wefind that, even with moderate tree planting densities, the implementation of SPSs can reduceGHGemissions by 2.6MgCO2e ha−1 yr−1 in relation to current practices, while increasing agriculture productivity and contributing to the restoration of severely degraded landscapes

Land-based measures to mitigate climate change: Potential and feasibility by country

Land-based climate mitigation measures have gained significant attention and importance in public and private sector climate policies. Building on previous studies, we refine and update the mitigation potentials for 20 land-based measures in >200 countries and five regions, comparing "bottom-up" sectoral estimates with integrated assessment models (IAMs). We also assess implementation feasibility at the country level. Cost-effective (available up to $100/tCO2 eq) land-based mitigation is 8-13.8 GtCO2 eq yr-1 between 2020 and 2050, with the bottom end of this range representing the IAM median and the upper end representing the sectoral estimate. The cost-effective sectoral estimate is about 40% of available technical potential and is in line with achieving a 1.5°C pathway in 2050. Compared to technical potentials, cost-effective estimates represent a more realistic and actionable target for policy. The cost-effective potential is approximately 50% from forests and other ecosystems, 35% from agriculture, and 15% from demand-side measures. The potential varies sixfold across the five regions assessed (0.75-4.8 GtCO2eq yr-1 ) and the top 15 countries account for about 60% of the global potential. Protection of forests and other ecosystems and demand-side measures present particularly high mitigation efficiency, high provision of co-benefits, and relatively lower costs. The feasibility assessment suggests that governance, economic investment, and socio-cultural conditions influence the likelihood that land-based mitigation potentials are realized. A substantial portion of potential (80%) is in developing countries and LDCs, where feasibility barriers are of greatest concern. Assisting countries to overcome barriers may result in significant quantities of near-term, low-cost mitigation while locally achieving important climate adaptation and development benefits. Opportunities among countries vary widely depending on types of land-based measures available, their potential co-benefits and risks, and their feasibility. Enhanced investments and country-specific plans that accommodate this complexity are urgently needed to realize the large global potential from improved land stewardship