Towards a better assessment of hydrological natural variability as a key adaptation strategy to climate change

尽管就气候变化对水资源的影响进行了所有研究，但很少有利益攸关方愿意承诺在遥远和不确定的未来实施适应战略。决策者更愿意适应投资回报较短的战略(**因此，适应自然变化将是减少当前和未来气候脆弱性的有效途径。有了对自然变异性的充分了解，就可以制定强有力的、无怨无悔的适应战略。这些战略将更容易向利益攸关方推销，因为它们不会像气候变化影响研究那样充满不确定性。这项研究计划建议深入研究水文科学中的自然气候变异性，以及如何获取这些知识，以最终改进工程设计实践，并为气候变化提供强有力的适应策略。主要目标是：*更好地描述和理解加拿大流域关键水文变量的自然变异性；并*对比自然变异性和气候变化对当前和未来气候的水文脆弱性的相对贡献。*为了实现这些长期目标，提出了以下四个具体目标：*--使用现有最长的传统时间序列研究选定流域的自然气候变异性；*--利用20世纪再分析项目的输出数据和远程气象网格数据，结合水文模拟，扩展关键站点和流域的历史记录；*--利用气候模型的三个大集合，进一步了解自然变异性；和*-基于1980-2010年的参考期，对比自然变异性和气候变化对未来不同时间范围的影响。*这项研究计划将使利益相关者更好地了解我们对自然气候变异性的脆弱性。适应自然变化，而不是气候变化，可能会转化为决策者采取更迅速的行动，同时提供针对气候变化的重大保护。考虑到到2050年，加拿大的气候变化成本估计在每年210亿至430亿美元之间，任何成功的适应战略都将为加拿大经济带来巨大的节省。

Despite all the research done on the impacts of climate change on water resources, few stakeholders have been willing to commit to adaptation strategies for a distant and uncertain future. Decision makers are more prepared to adapt to strategies with a shorter return on investment (**Consequently, adaptation to natural variability would be an efficient way to reduce vulnerabilities in the current and future climate. With an adequate knowledge of natural variability, robust no-regrets adaptation strategies could be devised. These strategies would be easier to sell to stakeholders because they would not be as clouded with uncertainties as those derived from climate change impact studies. This research program proposes an in-depth look at natural climate variability in hydrological sciences and how to harvest this knowledge to eventually improve engineering design practices and provide robust adaptation strategies to climate change. The main objectives are to:****o Better describe and understand the natural variability of key hydrological variables over Canadian watersheds; and***o Contrast the relative contributions of natural variability and climate change to hydrological vulnerability in both current and future climates.******To move toward these long term goals, the following four specific objectives are proposed:****- Study the natural climate variability on selected watersheds using the longest available traditional time-series;***- Extend the historical record for key stations and watersheds using output data from the 20th century reanalysis project and long-range meteorological gridded data, combined with hydrological modelling;***- Further our understanding of natural variability using three large ensembles of climate model simulations; and***- Based on the 1980-2010 reference period, to contrast the impacts of natural variability and climate change for various future time horizons.******This research program will provide stakeholders with a better understanding of our vulnerabilities to natural climate variability. Adapting to natural variability, as opposed to climate change, is likely to translate into more rapid actions by decision makers, while affording a significant protection against climate change. Considering that the cost of climate change in Canada is evaluated at between 21 and 43 billion dollars per year by 2050, any successful adaptation strategy will result in a very large saving for the Canadian economy.**