Suchergebnisse

Human intervention in forested ecosystems is hoped to perform a fundamental shift within the next decade by reverting current forest loss—a major source of CO2 emissions—to net forest gain taking up carbon and thus aiding climate change mitigation. The demanded extensive establishment of forests will change the local surface energy fluxes, and with it the local climate, in addition to competing with food and fiber production for land and water. Scenario building models encompass this competition for resources but have turned a blind eye to the biogeophysical (BGP) local surface energy flux disturbance so far. We combine the benefit of CO2 sequestration of afforestation/reforestation (A/R) with the additional incentive or penalty of local BGP induced cooling or warming by translating the local BGP induced temperature change to a CO2 equivalent. We then include this new aspect in the land-use model Model for Agricultural Production and their Impact on the Environment (MAgPIE) via modifying the application of the price on greenhouse gases (GHGs). This enables us to use MAgPIE to produce A/R scenarios that are optimized for both their potential CO2 sequestration and the CO2 equivalent local BGP effect, as well as the socio-economic trade-offs of A/R. Here we show that optimal A/R patterns are substantially altered by taking the local BGP effects into account. Considering local cooling benefits of establishing forests triples (+203.4%) the viable global A/R area in 2100 from 116 to 351 Mha under the conditions of the shared socioeconomic pathway 2 (SSP2) scenario driven by the same GHG price. Three quarters (76.0%, +179 Mha) of the additionally forested area is established in tropical climates alone. Therefore, a further neglect of BGP effects in scenario building models undervalues the benefit of tropical forests while simultaneously running the risk of proposing counterproductive measures at high latitudes. However, the induced focus on tropical forestation intensifies the competition with food production where forests contribute most to mitigation. A/R related trade-offs need to be considered alongside their climate benefit to inhibit unintentional harm of mitigation efforts. ; AXIS ; ERANET ; Federal Ministry of Education and Research (BMBF) ; German Aerospace Center (DLR) ; European Union ; Peer Reviewed

The project "Global greenhouse gas emission pathways until 2050" (2015-2017) aimed to develop transformation scenarios and strategies that both limit global warming to 2°C and take into account a number of environmental and sustainability criteria, such as food security, air quality, protection of aquatic and terrestrial ecosystems as well as socio-economic targets. This report presents the main findings of this work. The report opens with an assessment of the requirements for limiting future global temperature rise to less than 2°C. It then explores to what extend current climate policies, and especially the Nationally Determined Contributions (NDCs) support or endanger the achievement of the non-climate specific UN sustainable development goals (SDGs) and from here specifically looks at the sustainability im pacts of two main climate protection measures, i.e. biomass production and electricity generation from renewables. The report concludes with an assessment of sustainability-oriented strategies using an integrated energy-economy-climate and land-use modelling framework and highlights the potential of comprehensive climate policy approaches that align climate protection with sustainable development goals.