A climate-conditioned catastrophe risk model for UK flooding
A climate-conditioned catastrophe risk model for UK flooding
复制标题
DOI：
10.5194/nhess-23-891-2023
复制
发表时间：
2023-03
影响因子：
4.6
通讯作者：
P. Bates;J. Savage;O. Wing;Niall Quinn;C. Sampson;J. Neal;Andrew Smith
中科院分区：
文献类型：
--
作者：
P. Bates;J. Savage;O. Wing;Niall Quinn;C. Sampson;J. Neal;Andrew Smith
抽象。我们提出了一个透明的和验证的气候条件下的灾难性洪水模型为英国，模拟洪积，河流和沿海洪水的风险在1 arcsec的空间分辨率（20-25米）。使用英国气候预测2018（UKCP 18）气候模拟，在整个英国的历史，2020年，2030年，2050年和2070年条件下，产生了10个不同重现期的危险层。根据这些数据，计算了高于工业化前值的五个具体全球升温水平（0.6、1.1、1.8、2.5和3.3摄氏度）的货币损失。与以前的工作相比，该分析包含了更高层次的细节和细微差别，代表了我们目前对英国不断变化的洪水风险景观的最佳理解。验证对历史的国家重现期洪水图产生了关键的成功指数值为0.65和0.76，分别为英格兰和威尔士，和最高水位为卡莱尔2005年洪水复制的均方根误差（RMSE）为0.41米没有校准。这一技能水平类似于利用特定地点数据进行当地建模。预计2020年的年度损失为7.3亿英镑，与英国保险商协会报告的7.14亿英镑的观察值相比有所改善。之前基于政府数据的英国洪水损失估计值高出2.3倍，并且远远超出了我们模拟的损失分布，这可能是以观测为中心的。我们估计，在2020年的平均气候条件下，英国每年1%的洪水损失概率（变暖1.1摄氏度）比1990年（变暖0.6摄氏度）高出0.6%，如果所有国家的COP 26 2030碳减排承诺和“净零”承诺得到全面实施，这一增长可以保持在0.8%左右。仅执行COP 26承诺将使英国每年1%的洪水损失概率比1990年平均值增加23%，在碳减排目标未实现且气候敏感性高的“最坏情况”下可能增加37%。
Abstract. We present a transparent and validated climate-conditioned catastrophe flood model for the UK, that simulates pluvial, fluvial and coastal flood risks at 1 arcsec spatial resolution (∼ 20–25 m). Hazard layers for 10 different return periods are produced over the whole UK for historic, 2020, 2030, 2050 and 2070 conditions using the UK Climate Projections 2018 (UKCP18) climate simulations. From these, monetary losses are computed for five specific global warming levels above pre-industrial values (0.6, 1.1, 1.8, 2.5 and 3.3 ∘C). The analysis contains a greater level of detail and nuance compared to previous work, and represents our current best understanding of the UK's changing flood risk landscape. Validation against historical national return period flood maps yielded critical success index values of 0.65 and 0.76 for England and Wales, respectively, and maximum water levels for the Carlisle 2005 flood were replicated to a root mean square error (RMSE) of 0.41 m without calibration. This level of skill is similar to local modelling with site-specific data. Expected annual damage in 2020 was GBP 730 million, which compares favourably to the observed value of GBP 714 million reported by the Association of British Insurers. Previous UK flood loss estimates based on government data are ∼ 3× higher, and lie well outside our modelled loss distribution, which is plausibly centred on the observations. We estimate that UK 1 % annual probability flood losses were ∼ 6 % greater for the average climate conditions of 2020 (∼ 1.1 ∘C of warming) compared to those of 1990 (∼ 0.6 ∘C of warming), and this increase can be kept to around ∼ 8 % if all countries' COP26 2030 carbon emission reduction pledges and “net zero” commitments are implemented in full. Implementing only the COP26 pledges increases UK 1 % annual probability flood losses by 23 % above average 1990 values, and potentially 37 % in a “worst case” scenario where carbon reduction targets are missed and climate sensitivity is high.