Build in prevention and preparedness to improve climate resilience in coastal cities: Lessons from China’s GBA

Worldwide, a cocktail of climate change, urbanization, and population growth is increasing the vulnerability coastal communities to flood risk. Recent experience in urban management from China’s Greater Bay Area shows that building “prevention” “preparedness” into development plans essential for adaptation resilience. frequency cities has doubled since 2000 projected increase at least 5-fold by 2050.1NOAAThe State High Tide Flooding Annual Outlook.https://tidesandcurrents.noaa.gov/HighTideFlooding_AnnualOutlook.htmlDate: 2021Google Scholar Climate change accelerate rising sea level2Warrick R.A. Le Provost C. Meier M.F. Oerlemans J. Woodworth P.L. Changes level.in: Houghton J.T. Meira Filho L.G. Callander B.A. Harris N. Kattenberg A. Maskell K. Change 1995: The Science Change: Contribution Working Group 1 Second Assessment Report Intergovernmental Panel on Change. Cambridge University Press, 1996: 359-406Google severity extreme events including surges, storms, typhoons, hurricanes, etc.,3Aumann H.H. Ruzmaikin Teixeira Frequency severe storms global warming.Geophys. Res. Lett. 2008; https://doi.org/10.1029/2008GL034562Crossref PubMed Scopus (24) Google compounding situation. It anticipated present-day extreme-but-rare flooding will become commonplace within next few decades.4Taherkhani M. Vitousek S. Barnard Frazer Anderson T.R. Fletcher C.H. Sea-level rise exponentially increases frequency.Sci. Rep. 2020; 10: 6466https://doi.org/10.1038/s41598-020-62188-4Crossref (64) Over 40% lives 100 km coast, density flood-prone 25% toward 2050. Coastal are among most populous world are, many cases, economic (manufacturing, technology, trade, finance) centers where extensive activities agglomerated. Facing an flooding, economy risk, markedly more than inland counterparts (Figure 1). In last decade alone, average loss impact across globe estimated USD 6 billion 52 per year, respectively.4Taherkhani Flood risk exacerbated rapid urbanization. Conversion green blue-green spaces impervious surfaces disrupts natural water balance, reduces infiltration, surface runoff, exerts pressure often outdated dilapidated drainage systems.5O’Donnell E.C. Thorne C.R. Drivers future risk.Philos. Trans. A Math. Phys. Eng. Sci. 378: 20190216https://doi.org/10.1098/rsta.2019.0216Crossref (36) Where systems place, they generally designed withstand low-medium recurrence events.6Mariani Blacka M.J. Cox Coghlan I.R. Carley Wave overtopping structures. Physical model versus desktop predictions.J. Coast. 2009; 1: 534-538Google Unfortunately, changing these frequencies thus defense now insufficient protect communities. response risks, number have significantly improved their public infrastructure enhance adaptability resilience, such as retrofitting obsolete remove stormwater soon possible, introducing maintain cycles, seawalls/revetments armor coast. Yet despite investments, recent floods resulted huge damages losses—the Storm Ida September 2021 United States 95 billion7Stevens P. Hurricane Ida’s damage tally could top $95 billion, making it 7th costliest hurricane 2000. CNBC, 2021https://www.cnbc.com/2021/09/08/hurricane-idas-damage-tally-could-top-95-billion-making-it-7th-costliest-hurricane-since-2000-.htmlGoogle Scholar—suggesting some key components still missing practices pertinent There lacks consensus stakeholders urgency addressing until occur, reflected Europe.8Kim S.K. Bennett M.M. van Gevelt T. Joosse Urban agglomeration worsens spatial disparities adaptation.Sci. 2021; 11: 8446https://doi.org/10.1038/s41598-021-87739-1Crossref (2) Commonly, readiness given lower priority political agenda, investment insufficient. Undoubtedly, there urgent need improve prevalence significance, yet even critical developing countries.9Hallegatte Green Nicholls R.J. Corfee-Morlot Future losses major cities.Nat. Clim. Chang. 2013; 3: 802-806https://doi.org/10.1038/nclimate1979Crossref (1170) countries, China, Bangladesh, Vietnam, urbanization soil sealing continue apace. More people residing unprotected areas subject frequent defenses less developed, countries lack knowledge, social awareness adapt change. (GBA) represents one vulnerable regions,10Kulp S.A. Strauss B.H. New elevation data triple estimates sea-level flooding.Nat. Commun. 2019; 4844https://doi.org/10.1038/s41467-019-12808-zCrossref (385) covering 11 Hong Kong Macao nine mainland China namely Guangzhou, Shenzhen, Zhuhai, Foshan, Zhongshan, Dongguan, Huizhou, Jiangmen, Zhaoqing. GBA been prime region development, its GDP accounting 11.3% total national 2020. Located along southeast coastline, exposed strong rainstorms. According Observatory, hit 20 typhoons 1990s, 80% which brought intensive rainstorms (>100 mm/24 h) caused whole region.11Chan F.K.S. Chuah C.J. Ziegler A.D. Dąbrowski Varis O. Towards resilient Asian cities: Lessons learned Singapore.J. Clean. Prod. 2018; 187: 576-589https://doi.org/10.1016/j.jclepro.2018.03.217Crossref (54) light further two cities, Guangzhou specified first fifth (in terms induced 2050).9Hallegatte this threat, municipal governments established collaborative partnership embedded (FRM) strategies regional long-term plan. commentary, we consider threats facing GBA, developments FRM, valuable lessons can be applied elsewhere especially (pluvial) grand challenges GBA. Less 10% low-lying lands protected against with 1-in-50 years occurrence period,11Chan rainstorms, rise, storm surges threaten large assets cause substantial socio-economic ecological/environmental damages5O’Donnell Scholar—and becoming increasingly severe. While between 1989 2016, annual around 2 billion,12Karamouz Taheri Khalili Chen X. Building resilience management.J. Water Resour. Plan. Manage. https://doi.org/10.1061/(ASCE)WR.1943-5452.0001043Crossref (23) single event 2018 led 1.9 direct losses. Typhoon Mangkhut, strongest reliable meteorological records began, intense maximum inundation depth m. This typhoon cognate affected 4.5 million destroyed 11,000 homes.11Chan 2020, was ∼71 120 Most areas. experienced 1990s 2000s, rate 7%–9% land conversion year (70% area considered urban). Records suggest during 1980s through 26% (e.g., vegetation, farmland, forest) were converted concrete Further accommodate almost certainly see additional transformation open built-up areas, disrupting soil-water infiltration aggravating risks.13Chan Yang L.E. Scheffran Mitchell G. Adekola Griffiths Y. Li Lu Qi et al.Urban risks emerging Chinese delta: case Pearl River Delta.Environ. Policy. 122: 101-115https://doi.org/10.1016/j.envsci.2021.04.009Crossref (10) augmented commonly densely populated only cope 1-in-1 1-in-5 intervals, inadequate face FRM seek foster challenges. Similar other worldwide, individually predominately based traditional techno-fixes paradigms before 2010, aiming either keeping out or funneling away high-risk Diverse implemented, reservoirs, river channelization, embankments, water-gates, walls dikes, storage systems, underground tanks. Since 2014, nature-based solutions (such bio-infiltration bio-retention systems) also progressively integrated, leading strategy Sponge City construction. To strengthen Shenzhen retrofitted enhanced own able handle (and associated flooding) 1-in-100 recurrence. protection standard up 1-in-200 return period. preparations, Hato 2017 Mangkhut reinforced inundated homes infrastructures (roads railways) GBA11Chan Scholar—a revised approach needed. reviewing city-level strategies, identified: (better measures) “preparation” (sufficient understanding communication information, emergency plan, engagement). Without components, society cannot respond timely adequately impacts post-flood aid facilitate recovery after 2).11Chan Scholar,14Heuer L. Resilience Areas.https://www.royalhaskoningdhv.com/en/markets/flood-resilience-in-urban-areas/5733Date: 2018Google respects seen progress years. Increasing recognition importance emphasized integrated synchronized framework region. Guided Outline Development Plan Guangdong-Hong Kong-Macao issued Council 2019, Joint Environmental Protection Combating established. working group aims overcome potential barriers cross-boundary legislations, policies, technologies inherited principle “one country, systems” had place 1997. information sharing action coordination. attempts connectivity coherence facilities; co-produce share co-learning experiences community-based prevention, preparedness, post-disaster recovery; develop programs enhancing resilience.8Kim GBA’s published extensively promoted Particularly, advantages media smart highlighted. Sensors wireless networks Internet Things enable collation real-time localized data, display disseminate early warnings joint public-private partnership, pre-designed pre-practiced procedures, before, during, events. Local authorities bureaus bureaus) work closely each international organizations World Meteorological Organization (WMO) monitor exchange about rainfall patterns, local scale. then shared regularly transparently raise awareness, reduce damages, deliver actions relocation, rescue) effectively. surveys revealed 90% households form preparedness typhoon-specific measures. effectiveness put test proved successful 2018.15Chan E.Y.Y. Man A.Y.T. Lam H.C.Y. Chan G.K.W. Hall B.J. Hung K.K.C. Is household short-term reduction super subtropical city?.Int. Environ. Public Health. 16: 596https://doi.org/10.3390/ijerph16040596Crossref (19) inclusion signifies shift engineering paradigm integration engineered (public infrastructure) engaging multiple actors involving civil society. One lesson solely relying (covering gray sponge city initiative) might not sufficient enough safeguard dimension (mobilizing engagement preparation prevent), plans, effective juncture fight address crisis. road upcoming 26th Nations Conference Parties (COP26) Glasgow (UK) paved good opportunities step ambition avert worst intensity mitigation responses, well exposure remain successfully moving improving disaster reduction. hot themes low-carbon neutralization likely dominate November’s COP26 discussions, particularly developed important topic requires attention, engagement, co-production policymakers, stakeholders, non-governmental organizations, Many exploring how meet commitment set nationally determined contributions plans. National Strategy Adaptation, strengthening monitoring warning capabilities participation principles. Following guidance, socially inclusive scheme included newly released Regional 2050.8Kim gained transboundary prevention measures via technologies) those who conventional techno-fixes, uptake policy initiatives (Sendai Framework Disaster Reduction, WMO), collaborate, establish climatic risks. Additional concerted efforts nations required education (including generations, mobile phones, apps, internet sources) big (for better “prevention”) popular this. Relevant should planning Master Plans 2050 beyond. recognizing translating does lead complacency geopolitically region, conclude encourage coordinated study funded Key Research Program (no. 2019YFA0606903 , 2019YFC1510400 ), Natural Foundation 41971040 41850410497 Ningbo Technology Bureau (grant no. 201401C 5008005 ). F.K.S.C. W.Y.C. authors contribute equally leading, designing, supervising, writing, editing, reviewing, being responsible all figures text manuscript. Y.S., Y.D.C., W.W.H., W.-Q.C., J.G., J.L., Y.P., J.H., X.G., X.L., P.Y.K.C., M.T.-M Y.-G.Z. senior equivalent workload providing ideas, Other co-authors graphic designs, collection.