Projected landscape-scale repercussions of global action for climate and biodiversity protection.

Land conservation and increased carbon uptake on land are fundamental to achieving the ambitious targets of the climate and biodiversity conventions. Yet, it remains largely unknown how such ambitions, along with an increasing demand for agricultural products, could drive landscape-scale changes and affect other key regulating nature's contributions to people (NCP) that sustain land productivity outside conservation priority areas. By using an integrated, globally consistent modelling approach, we show that ambitious carbon-focused land restoration action and the enlargement of protected areas alone may be insufficient to reverse negative trends in landscape heterogeneity, pollination supply, and soil loss. However, we also find that these actions could be combined with dedicated interventions that support critical NCP and biodiversity conservation outside of protected areas. In particular, our models indicate that conserving at least 20% semi-natural habitat within farmed landscapes could primarily be achieved by spatially relocating cropland outside conservation priority areas, without additional carbon losses from land-use change, primary land conversion or reductions in agricultural productivity.

Integrating degrowth and efficiency perspectives enables an emission-neutral food system by 2100.

Degrowth proponents advocate reducing ecologically destructive forms of production and resource throughput in wealthy economies to achieve environmental goals, while transforming production to focus on human well-being. Here we present a quantitative model to test degrowth principles in the food and land system. Our results confirm that reducing and redistributing income alone, within current development paradigms, leads to limited greenhouse gas (GHG) emission mitigation from agriculture and land-use change, as the nutrition transition towards unsustainable diets already occurs at relatively low income levels. Instead, we show that a structural, qualitative food system transformation can achieve a steady-state food system economy that is net GHG-neutral by 2100 while improving nutritional outcomes. This sustainable transformation reduces material throughput via a convergence towards a needs-based food system, is enabled by a more equitable income distribution and includes efficient resource allocation through the pricing of GHG emissions as a complementary strategy. It thereby integrates degrowth and efficiency perspectives.

Structural investigation of tailings flocculation and consolidation via quantitative 3D dual fluorescence/reflectance confocal microscopy.

HYPOTHESIS: Mechanistic understanding of particle-flocculant interactions and its link to the resulting floc structure is essential for developing tailings treatments with enhanced consolidation rates. A noninvasive, in-situ visualization of the floc formation and the consequent sediment microstructure via tri-dimensional laser scanning confocal microscopy (LSCM) can enable establishing the quantitative link between the flocculation conditions and bulk properties of the resulting sediment structures. EXPERIMENTS: A dual fluorescence/reflectance confocal imaging protocol is developed to non-invasively detect morphological changes in dense oil sands tailings during flocculation with an anionic polymer and the subsequent sediment compaction stages for three different polymer dosages. The image reconstruction is developed to quantify the organics/clay volume fractions in the sediment and the floc network characteristics through the pseudo fractal dimension which are related to the bulk rheological properties following a 5-day densification period. FINDINGS: In-situ imaging of the flocculation process gives insights into the variable floc density and size at different stages of mixing. The acquired 3D images of the flocculated sediment reveal that bitumen remains within the flocs. The increase in the polymer dosage results in the reduction of the sediment fractality and strength attributed to the possible formation of more swelled floc structures. Clay reflectance detection is validated using a model kaolinite clay dispersion. The developed methodology may ultimately be used as a guiding tool for standard screening of the new flocculants and flocculation protocols for various mineral tailings systems.