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Abstract |
Adaptation to climate change calls for local responses. The impact of a 2020-30 climate scenario was assessed on a 54,000 ha Mediterranean district characterized by a variety of farming systems (FS), ranging from low-input rainfed (42% of the district area and 16% of the district net income) to high-input irrigated. Climate was generated with a Regional Atmospheric Modelling System nested into a full coupled atmosphere-ocean global simulation model, under the A1B emission scenario. Crop responses to climate were assessed using EPIC after calibration. The Temperature Humidity Index was used to assess the impact on dairy cow milk yield. Farmer choices were simulated on 13 representative FS by an hybrid model of supply, territory and farm. The adaptive choices were simulated through Discrete Stochastic Programming, fed by probability distribution functions output of crop and animal models. The expected decrease in spring rainfall (-33%) will affect hay-crop production and the net income (NI) of rainfed livestock farms (-5 to -12%). The increased summer temperature will affect dairy cows NI up to -5.9%. Rice production is expected to increase up to +10%. Overall, the NI of irrigated and rainfed farms will be -2.1% and -5.4% of the current NI respectively, with livestock FS being the most affected and rice and horticultural FS the most resilient. Results will provide an ideal mediating object for engaging policy makers and stakeholders in designing visionary adaptive strategies. No Label |
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Abstract |
Problems related to food security and sustainable development are complex (Ericksenet al., 2009) and require consideration of biophysical, economic, political, and social factors, as well as their interactions, at the level of farms, regions, nations, and globally. While the solution to such societal problems may be largely political, there is a growing recognition of the need for science to provide sound information to decision-makers (Meinke et al., 2009). Achieving this, particularly in light of largely uncertain future climate and socio-economic changes, will necessitate integrated assessment approaches and appropriate integrated assessment modeling (IAM) tools to perform them. Recent (Ewertet al., 2009; van Ittersumet al., 2008) and ongoing (Rosenzweiget al., 2013) studies have tried to advance the integrated use of biophysical and economic models to represent better the complex interactions in agricultural systems that largely determine food supply and sustainable resource use. Nonetheless, the challenges for model integration across disciplines are substantial and range from methodological and technical details to an often still-weak conceptual basis on which to ground model integration (Ewertet al., 2009; Janssenet al., 2011). New generations of integrated assessment models based on well-understood, general relationships that are applicable to different agricultural systems across the world are still to be developed. Initial efforts are underway towards this advancement (Nelsonet al., 2014; Rosenzweiget al., 2013). Together with economic and climate models, crop models constitute an essential model group in IAM for large-area cropping systems climate change impact assessments. However, in addition to challenges associated with model integration, inadequate representation of many crops and crop management systems, as well as a lack of data for model initialization and calibration, limit the integration of crop models with climate and economic models (Ewertet al., 2014). A particular obstacle is the mismatch between the temporal and spatial scale of input/output variables required and delivered by the various models in the IAM model chain. Crop models are typically developed, tested, and calibrated for field-scale application (Booteet al., 2013; see also Part 1, Chapter 4 in this volume) and short time-series limited to one or few seasons. Although crop models are increasingly used for larger areas and longer time-periods (Bondeauet al., 2007; Deryng et al., 2011; Elliottet al., 2014) rigorous evaluation of such applications is pending. Among the different sources of uncertainty related to climate and soil data, model parameters, and structure, the uncertainty from methods used to scale-up crop models has received little attention, though recent evaluations indicate that upscaling of crop models for climate change impact assessment and the resulting errors and uncertainties deserve attention in order to advance crop modeling for climate change assessment (Ewertet al., 2014; R¨ otteret al., 2011). This reality is now reflected in the scientific agendas of new international research projects and programs such as the Agricultural Model Intercomparison and Improvement Project (AgMIP; Rosenzweiget al., 2013) and MACSUR (MACSUR, 2014). In this chapter, progress in evaluation of scaling methods with their related uncertainties is reviewed. Specific emphasis is on examining the results of systematic studies recently established in AgMIP and MACSUR. Main features of the respective simulation studies are presented together with preliminary results. Insights from these studies are summarized and conclusions for further work are drawn. No Label |
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