Defining national net zero goals is critical for food and land use policy

The identification of agriculture and land use configurations that achieve net zero (NZ) greenhouse gas emissions is critical to inform appropriate land use and food policy, yet national NZ targets lack consistent definitions. Here, 3000 randomised scenarios projecting future agricultural production and compatible land use combinations in Ireland were screened using ten NZ definitions. When aggregating carbon dioxide, methane, and nitrous oxide emissions using various methods, 1–85% of scenarios met NZ criteria. Despite considerable variation, common actions emerged across definitions, including high rates of afforestation, organic soil re-wetting, and cattle destocking. Ambitious technical abatement of agricultural emissions moderated, but could not substitute, these actions. With abatement, 95th percentile milk output varied from 11–91% of 2021 output, but was associated with reductions of up to 98% in suckler-beef production, and a 47–387% increase in forest cover. Achieving NZ will thus require transformation of Ireland’s land sector. Lagging land use change effects require urgent action, but sustaining a just transition will require visioning of future NZ land use combinations supporting a sustainable and resilient food system, alongside an expanding circular bioeconomy. We provide new insight into the sensitivity of such visioning to NZ definitions, pointing to an urgent need for international consensus on the accounting of methane emissions in NZ targets

A safe agricultural space for biodiversity

Agriculture is the main driver of the rapid collapse of biodiversity, upon which all life on Earth, including agricultural production, depends. As we face the challenge of feeding a growing human population under a changing climate regime, the pressure on biodiversity is expected to further intensify. While the potential to expand and improve natural habitats for biodiversity conservation has been widely explored in large-scale scenarios of agricultural systems, the critical role of agricultural landscapes’ management on halting the loss of biodiversity remains unexplored at this scale. We argue that, to achieve an effective conservation of biodiversity (both natural and agricultural), the combined multivariate effects of agriculture on biodiversity must be accounted for, including its surface area as well as its management. Based on a literature review, we identified the main biodiversity pressures stemming from agriculture: land-use change, contribution to climate change, water withdrawal, pesticide pollution, nutrient (nitrogen and phosphorus) pollution, and landscape and farm-scale simplification (of croplands and pastures). For each one, we proposed a critical boundary, based on reviews of studies covering a range of taxa, biodiversity metrics, and biomes, below or above which negative impacts on biodiversity are minimized or positive effects arise. Implemented simultaneously, the identified boundaries would integrate biodiversity conservation within and across farmlands and minimize agriculture’s far-reaching impacts on biodiversity. We present a framework called “agricultural boundaries for biodiversity” that will allow to explore the potential of developing agricultural systems that effectively reconcile food production and biodiversity conservation at large scales

Influence of nature values on environmental assessments in the ESGAP framework

Environmental metrics are used to describe the state of the environment in order to help actors responsible for implementing public policies for development and environmental protection to evaluate the effectiveness of their actions. To describe the state of the environment in Senegal, we use the ESGAP method, which consists of evaluating each dimension of the environment in biophysical units, in order to estimate at the national level, the capacity of natural capital to perform its environmental functions. The strong environmental sustainability (SES) index informs the gap between the current state of the environment and the environmental sustainability objectives. Four functions (the renewal of natural resources, the capacity of ecosystems to absorb pollution up to their critical load, the maintenance of biodiversity, and the impact of the environment on health and well-being) are measured by 33 indicators. The main challenge in Senegal is to understand the respective influences of the data quality supporting indicators, the choice of one indicator instead of another to inform one dimension of the environment and the weight of each environmental dimension on the aggregated SES index. For that, we performed a global sensitivity analysis (GSA). We found that the weights of dimensions with low uncertainty and extreme score (‘UNESCO sites’, ’Terrestrial ecosystems’ and ’Soil resources’) are highly influencing the aggregated SES index. They are responsible of 66 % of the SES index variability in the GSA. Then the choice between indicators with very different scores to inform one dimension of the environment was the second group of influential variables. For example, the choice between the ‘biodiversity intactness index’, the ‘red list index’ or the ‘mean species abundance’ to inform the ‘terrestrial ecosystem’ dimension is highly influencing the aggregated SES index because they give different scores (respectively 89, 94 and 51). Finally, the choices between databases given different results for the same indicators are the third influential group of variables. For example, the choice between two data sources to inform the soil resource in Senegal is responsible of significant part of the SES index variability in the GSA. We concluded that participatory approaches to introduce negotiated values in the evaluation of the state of the environment through weights between the dimensions of the environment was highly important, but only for well-informed indicators. Thus, the participatory process and the data gathering are complementary to evaluate a robust and relevant state of the environment

Persistence of Toscana virus in sugar and blood meals of phlebotomine sand flies: epidemiological and experimental consequences

International audienceAbstract Many virological studies have tested the persistence of enveloped RNA viruses in various environmental and laboratory conditions and shown their short-term persistence. In this article, we analyzed Toscana virus (TOSV) infectivity, a pathogenic sandfly-borne phlebovirus, in two different conditions: in the sugar meal and blood meal of sand flies. Our results showed that TOSV RNA was detectable up to 15 days in sugar solution at 26 °C and up to 6 h in blood at 37 °C. Moreover, TOSV remains infective for 7 days in sugar solution and for minimum 6 h in rabbit blood. TOSV has shown persistent infectivity/viability under different conditions, which may have important epidemiological consequences. These results strengthen new hypotheses about the TOSV natural cycle, such as the possibility of horizontal transmission between sand flies through infected sugar meal

Assessing the impact of increased legume production in Europe on global agricultural emissions

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Réduire de moitié l'utilisation de l'azote minéral dans l'agriculture européenne : Perspectives offertes par les modèles d'utilisation des sols à plusieurs échelles

International audienceThis paper explores the effects of a public policy that reduces by 50% the use of mineral nitrogen in European agriculture. Our results show that, for the European Union, halving mineral fertilizer use leads to: a decrease in agricultural production, a substantial increase in nitrogen use efficiency, lower use of organic fertilizer and a loss of agricultural competitiveness. At the global level, it leads to greater nitrogen consumption if no measure is taken on the demand side. Ultimately, our research highlights the critical importance of supply side adjustments, particularly in terms of cropland area expansion.Cet article explore les effets d'une politique publique qui réduit de 50 % l'utilisation de l'azote minéral dans l'agriculture européenne. Nos résultats montrent que, pour l'Union européenne, la réduction de moitié de l'utilisation d'engrais minéraux entraîne : une diminution de la production agricole, une augmentation substantielle de l'efficacité de l'utilisation de l'azote, une moindre utilisation d'engrais organiques et une perte de compétitivité de l'agriculture. Au niveau mondial, cela conduit à une plus grande consommation d'azote si aucune mesure n'est prise du côté de la demande. En fin de compte, notre recherche met en évidence l'importance cruciale des ajustements du côté de l'offre, en particulier en termes d'expansion des surfaces cultivées

The future of social-ecological systems at the crossroads of quantitative and qualitative methods

International audienceUrgent calls to transform societies toward more sustainability make the practice of anticipation more and more necessary. The progressive development of computational technologies has opened room for a growing use of quantitative methods to explore the future of social-ecological systems, in addition to qualitative methods. This warrants investigating issues of power relationships and discontinuities and unknowns that arise when mingling quantitative and qualitative anticipatory methods. We first reflected on the semantics attached to these methods. We then conducted a comparative analysis on the way the articulation of quantitative and qualitative methods was conducted, based on an in-depth analysis of a set of eleven anticipatory projects completed by several external case studies. We propose insights to classify projects according to the timing (successive, iterative or convergent) and the purpose of the articulation (imagination, refinement, assessment and awareness raising). We use these insights to explore methodological implications and power relationships and then discuss the ways to inform or frame anticipatory projects that seek to combine these methods

Combining mitigation strategies to increase co-benefits for biodiversity and food security

International audienceWorld agriculture needs to find the right balance to cope with the trilemma between feeding a growing population, reducing its impact on biodiversity and minimizing greenhouse gas (GHG) emissions. In this paper, we evaluate a broad range of scenarios that achieve 4.3 GtCO2,eq/year GHG mitigation in the Agriculture, Forestry and Other Land-Use (AFOLU) sector by 2100. Scenarios include varying mixes of three GHG mitigation policies: second-generation biofuel production, dietary change and reforestation of pasture. We find that focusing mitigation on a single policy can lead to positive results for a single indicator of food security or biodiversity conservation, but with significant negative side effects on others. A balanced portfolio of all three mitigation policies, while not optimal for any single criterion, minimizes trade-offs by avoiding large negative effects on food security and biodiversity conservation. At the regional scale, the trade-off seen globally between biodiversity and food security is nuanced by different regional contexts

Réduire de moitié l'utilisation de l'azote minéral dans l'agriculture européenne : aperçu des modèles multi-échelles d'utilisation des sols

In this paper, we explore the effects of a public policy that reduces by 50% the use of mineral nitrogen in European agriculture. We use two techno-economic models to investigate the impacts on agricultural production, prices, and land use changes at the EU and global levels. Results show that halving synthetic fertilizer use leads to a decrease in agricultural production, a substantial increase in nitrogen use efficiency, and lower use of organic fertilizer. More importantly, we show that the results will critically depend on the potential for supply side adjustment, particularly, regarding the expansion of cropland area.Dans cet article, nous explorons les effets d'une politique publique qui réduit de 50% l'utilisation de l'azote minéral dans l'agriculture européenne. Nous utilisons deux modèles technico-économiques pour étudier les impacts sur la production agricole, les prix et les changements d'utilisation des terres aux niveaux européen et mondial. Les résultats montrent que la réduction de moitié de l'utilisation des engrais synthétiques entraîne une diminution de la production agricole, une augmentation substantielle de l'efficacité de l'utilisation de l'azote et une utilisation moindre des engrais organiques. Plus important encore, nous montrons que les résultats dépendront de manière critique du potentiel d'ajustement de l'offre, notamment en ce qui concerne l'expansion des terres cultivées