The changing climate makes it more difficult to manage water resources and food production sustainably. Various adaptation measures have been proposed to moderate the negative impacts of climate change; however, implementation of these measures may be hampered by other factors even if the benefits are acknowledged—a situation termed “soft adaptation limits” by the IPCC. We hypothesized that societal rules can be a potential barrier to adaptive action if they are too fixed, because such rules have coevolved with the interactions between the past climate and human activities. To test this hypothesis, we present a framework based on the assumption that associated societal rules of Japan's matured irrigation systems are potential barriers to adaptation. The framework consisted of two process-based models, one to evaluate the water deficit risk and one to evaluate the benefits of optimizing rice yield and quality. We applied each model to an experiment in which we shifted the current transplantation date by 1 week for up to 5 weeks before and after the current date under the historical (1981–2000) and RCP 2.6 and 8.5 (2011–2030 and 2031–2050) scenarios. We revealed two contrasting development pathways in the study watershed. Soft adaptation limits imposed by water availability will occur by 2030 if farmers optimize for quality, whereas mutual benefits to farmers and river administrators will be achieved if farmers seek yield. We argue that more participatory research with stakeholder engagement, as well as policy discussions about these possible developments, is needed to ensure successful adaptation.

中文翻译：

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日本水稻耦合系统适应性行动的潜在障碍：预测软适应极限的框架

气候变化使得可持续管理水资源和粮食生产变得更加困难。已提出各种适应措施来减轻气候变化的负面影响；然而，即使这些措施的好处得到承认，这些措施的实施也可能会受到其他因素的阻碍——这种情况被IPCC称为“软适应限制”。我们假设，如果社会规则过于固定，则可能成为适应性行动的潜在障碍，因为这些规则是与过去气候和人类活动之间的相互作用共同演化的。为了检验这一假设，我们提出了一个基于日本成熟灌溉系统的相关社会规则是适应的潜在障碍这一假设的框架。该框架由两种基于过程的模型组成，一种用于评估缺水风险，另一种用于评估优化水稻产量和质量的效益。我们将每个模型应用于一项实验，其中在历史（1981-2000）和 RCP 2.6 和 8.5（2011-2030 和 2031-2050）下，将当前移植日期移动 1 周，持续当前日期前后最多 5 周。 ）场景。我们揭示了研究分水岭中两种截然不同的发展路径。如果农民优化质量，到 2030 年，水资源供应所施加的软适应限制将出现，而如果农民追求产量，农民和河流管理者将实现互惠互利。我们认为，需要利益相关者参与更多的参与性研究，以及关于这些可能的发展的政策讨论，以确保成功的适应。