The Consortium on Risk in the Environment: Diagnostics, Integration, Benchmarking, Learning and Elicitation (CREDIBLE)

自然灾害事件每年夺去数千人的生命，经济损失达数十亿美元。自然灾害事件造成财富损失的风险正在以超过财富创造速度的速度增加。因此，自然灾害风险管理人员有可能通过充分了解情况的行动，大大减少社会影响并保护经济资产。进一步说，环境科学通过为风险管理者的行动提供信息，可以将数百万美元的研究投资转化为数十亿美元的经常性社会和经济效益。然而，要真正有效地发挥这一作用，环境科学必须明确认识到风险评估中不确定性的存在及其影响。不确定性在自然灾害中无处不在，这既源于灾害事件本身固有的不可预测性，也源于这些事件与环境和人相互作用的复杂方式。它也非常复杂，具有空间和时间结构（例如风暴聚集），测量非常稀疏，特别是对于大震级事件，损失通常是危害级别的高度非线性函数。自然灾害科学家和风险管理人员（如保险公司的精算师）倾向于明确地评估“简单的”不确定性，并将其余部分分配给较大的误差范围。我们项目的第一个目标是引入统计技术，允许一些不确定性从误差范围中移出，并返回到明确的表示中，这将大大提高不确定性和风险评估的透明度和可防御性。最明显的候选者是根据先前事件的目录拟合的风险模型（我们可以引入关于模型参数和模型类别的不确定性），以及风险对环境的“足迹”模型的局限性，以及风险事件带来的损失。第二个目标是发展方法，使我们能够评估不确定性的较难量化的方面，例如与未来情景（如温室气体排放情景或人口增长预测）相关的概率。第三个目标是改善不确定性和风险的可视化和沟通，以促进行动之间选择的共同所有权，并缩小行动意图（例如，建造堤坝，或重新安置生活在高风险地区的一群人）与行动完成之间的差距。在自然灾害中，这一差距可能很大，因为行动的成本很高，许多人可能受到影响，而且行动可能需要几年时间才能完成。最终，每个人都能从更好的自然灾害风险管理中受益，尽管受益的性质取决于地理位置。例如，在英国，主要的危险是洪水，这是一个特别不确定的领域，因为降雨和沿海风暴潮很可能受到气候变化的影响。第二个危险是干旱，导致热应激和水资源短缺。我们的项目对内陆洪水、风暴和干旱有明确的研究方向。世界上其他地区更容易受到火山或地震的影响，我们的项目有火山灰、火山爆发时发现的泥石流（即火山泥流，雪崩类似）和地震。在未来，可能会出现新的危险，例如空间天气对通信的影响。我们项目的一个关键部分是开发一种通用的方法，可以跨越现有和新出现的危险。

Natural hazard events claim thousands of lives every year, and financial losses amount to billions of dollars. The risk of losing wealth through natural hazard events is now increasing at a rate that exceeds the rate of wealth creation. Therefore natural hazards risk managers have the potential, through well-informed actions, to significantly reduce social impacts and to conserve economic assets. By extension, environmental science, through informing the risk manager's actions, can leverage research investment in the low millions into recurring social and economic benefits measured in billions. However, to be truly effective in this role, environmental science must explicitly recognize the presence and implications of uncertainty in risk assessment.Uncertainty is ubiquitous in natural hazards, arising both from the inherent unpredictability of the hazard events themselves, and from the complex way in which these events interact with their environment, and with people. It is also very complicated, with structure in space and time (e.g. the clustering of storms), measurements that are sparse especially for large-magnitude events, and losses that are typically highly non-linear functions of hazard magnitude. The tendency among natural hazard scientists and risk managers (eg actuaries in insurance companies) is to assess the 'simple' uncertainty explicitly, and assign the rest to a large margin for error.The first objective of our project is to introduce statistical techniques that allow some of the uncertainty to be moved out of the margin for error and back into an explicit representation, which will substantially improve the transparency and defensibility of uncertainty and risk assessment. Obvious candidates for this are hazard models fitted on a catalogue of previous events (for which we can introduce uncertainty about model parameters, and about the model class), and limitations in the model of the 'footprint' of the hazard on the environment, and the losses that follow from a hazard event.The second objective is to develop methods that allow us to assess less quantifiable aspects of uncertainty, such as probabilities attached to future scenarios (eg greenhouse gas emissions scenarios, or population growth projections). The third objective is to improve the visualisation and communication of uncertainty and risk, in order to promote a shared ownership of choices between actions, and close the gap between the intention to act (eg, to build a levee, or relocate a group of people living in a high-risk zone) and the completion of the act. In natural hazards this gap can be large, because the cost of the act is high, many people may be affected, and the act may take several years to complete.Ultimately, everyone benefits from better risk management for natural hazards, although the nature of the benefits will depend on location. In the UK, for example, the primary hazard is flooding, and this is an area of particular uncertainty, as rainfall and coastal storm surges are likely to be affected by changes in the climate. A second hazard is drought, leading to heat stress and water shortages. Our project has explicit strands on inland flooding, wind-storms, and droughts. Other parts of the world are more affected by volcanoes or by earthquakes, and our project has strands on volcanic ash, debris flows as found in volcanic eruptions (ie lahars; avalanches are similar), and earthquakes. In the future, new hazards might emerge, such as the effect of space weather on communications. A key part of our project is to develop generic methods that work across hazards, both current and emerging.