Adaptation response surfaces for managing wheat under perturbed climate and CO2 in a Mediterranean environment

Abstract

Adaptation of crops to climate change has to be addressed locally due to the variability of soil, climate and the specific socioeconomic settings influencing farm management decisions. Adaptation of rainfed cropping systems in the Mediterranean is especially challenging due to the projected decline in precipitation in the coming decades, which will increase the risk of droughts. Methods that can help explore uncertainties in climate projections and crop modelling, such as impact response surfaces (IRSs) and ensemble modelling, can then be valuable for identifying effective adaptations. Here, an ensemble of 17 crop models was used to simulate a total of 54 adaptation options for rainfed winter wheat (Triticum aestivum) at Lleida (NE Spain). To support the ensemble building, an ex post quality check of model simulations based on several criteria was performed. Those criteria were based on the "According to Our Current Knowledge" (AOCK) concept, which has been formalized here. Adaptations were based on changes in cultivars and management regarding phenology, vernalization, sowing date and irrigation. The effects of adaptation options under changed precipitation (P), temperature (T), [CO 2 ] and soil type were analysed by constructing response surfaces, which we termed, in accordance with their specific purpose, adaptation response surfaces (ARSs). These were created to assess the effect of adaptations through a range of plausible P, T and [CO 2 ] perturbations. The results indicated that impacts of altered climate were predominantly negative. No single adaptation was capable of overcoming the detrimental effect of the complex interactions imposed by the P, T and [CO 2 ] perturbations except for supplementary irrigation (sI), which reduced the potential impacts under most of the perturbations. Yet, a combination of adaptations for dealing with climate change demonstrated that effective adaptation is possible at Lleida. Combinations based on a cultivar without vernalization requirements showed good and wide adaptation potential. Few combined adaptation options

Global wheat production with 1.5 and 2.0°C above pre‐industrial warming

“…This conclusion is consistent with field observations in a range of growing environments (Kimball, ; O'Leary et al, ) and with a rate of 0.06% yield increase per ppm [CO 2 ] derived from a meta‐analysis of simulation results (Challinor, Martre, et al, ; Challinor, Watson, et al, ). The CO 2 fertilization effect is often found to dominate model‐based projections of future global wheat productivity (Rosenzweig et al, ; Ruiz‐Ramos et al, ; Wheeler & von Braun, ), but with substantial uncertainties and regional differences (Deryng et al, ; Kersebaum & Nendel, ; Müller et al, ).…”

Determining sectoral and regional sensitivity to climate and socio-economic change in Europe using impact response surfaces

“…The preceding discussion emphasises how the quantification of impact indicators using a single impact model may neglect important parameter and structural uncertainties that are increasingly being investigated using ensemble approaches (Warszawski et al 2014). In principle, information about the uncertainty of impact estimates can be addressed in IRS analysis, as has been demonstrated in single-sector and location-specific IRS studies that have employed ensembles of impact models (Fronzek et al 2011;Pirttioja et al 2015;Ruiz-Ramos et al 2018). Unfortunately, such ensembles were not available in this study.…”

Global Response Patterns of Major Rainfed Crops to Adaptation by Maintaining Current Growing Periods and Irrigation

“…Different agronomic management options have been proposed as adaptation strategies against temperature‐induced yield losses. Most commonly, these include a shift of sowing dates, choice of cultivars with adjusted phenology, and irrigation (Challinor et al, ; Olesen et al, ; Parent et al, ; Ruiz‐Ramos et al, ; Semenov et al, ; Tack et al, ). Sowing dates can be advanced or delayed to match the most favorable thermal conditions and to exploit a longer growing season (Olesen et al, ; Sacks et al, ; Waha et al, ).…”

“…Although some studies assessed these adaptation strategies at local to regional scales (Burke & Emerick, ; Parent et al, ; Ruiz‐Ramos et al, ; Semenov et al, ), their aggregated effects at the global scale remain an open question. Global projections of climate change impacts usually do not consider the adaptation potentials of agricultural system in response to climate change and might therefore overestimate impacts on crop yields and production.…”