Designing scenarios for upscaling climate-smart agriculture on a small tropical island

Climate smart agriculture (CSA) is proposed to meet the major challenges of feeding nine billion people by 2050, adapting systems to climate change and mitigating anthropogenic GHG emissions. These challenges are salient in tropical island regions that are particularly vulnerable. While many technical solutions based on agroecology and bioeconomy have been proposed to promote CSA, there is little work on the issue of barriers to the transition towards such systems, which remains slow. There is a need to develop methods to model possible futures to cope with the imposed constraints of climate change and to identify relevant agronomic and policy levers to achieve this goal. A methodological framework was proposed to design scenarios for upscaling CSA, which was applied in Guadeloupe. The multi-scale and transdisciplinary framework consists of five steps: farm typology building, diagnosis of farming systems from a survey on a sample of farms, design of a prototype of climate-smart farming system, field experimenting, and modeling scenarios to identify levers that can reach the CSA objectives at the regional level under future climate conditions. While new agricultural systems based on agroecology and bioeconomy have the potential to reduce the impacts of climate change, mitigate GHGs, and increase food autonomy, results revealed that many lock-in effects have to be relaxed, increasing workforce availability at the regional scale, reorientating public incentives towards agroecological systems, increasing profitability of CSA products, improving the work efficiency of farmers, and reducing their risk aversion. In the best scenario designed, the potential impact of climate hazards was reduced by 12.5%, the nutritional performance at the regional scale was tripled with 6.0 fed people/ha/yr, the GHG balance switched from net emissions to a sequestration of 0.7 tCO2eq/ha/yr, while the labor productivity rose to $26.5/h (+14%). Compared to that of the baseline situation, the public cost for mitigating 1 tCO2eq was $432. New ambitious policies targeting farmers' constraints are required to increase CSA. There is a need to develop more stakeholder platforms in which all issues and possible levers are discussed, and transition scenarios are co-designed. The approach proposed herein can be used to feed discussions on such platforms. Research must be continued in the “redesign” field to model transition in a dynamic way, given the uncertainty of many crucial aspects such as climate change scenarios, market evolution, technical progress in agroecology, and farmers' behavior.