11wtwco.comNaturalCatastropheReview:Expertinsights,lessonslearned,andoutlookJanuary–June2023ForewordRecentEventsOutlookContactsandInformation1/Foreword032/RecentEvents072.1Worldsapart:ImplicationsoftheTürkiyeearthquakesforCalifornia082.2IstherecordnumberofconvectivestormsinthefirstquarterasignofthingstocomeintheU.S.?142.3AnunusuallylargenumberofCategory5tropicalcyclones162.4BuildingbackbetterfollowingTropicalCycloneGabrielle182.5Countingthecostsofclimateandland-usechangeaftertheChileanWildfires222.6Outofthewoods:HowfarwillCanada’swildfiresspread?242.7Aviewofcatastrophicfloodingfromacrosstheworld292.8Emilia-Romagnafloods:Aproductofurbanizationandclimatechange322.9WhyweretheresofewEuropeanwinterwindstormsin2022/2023?343/Outlook383.1InthetropicalPacific,ElNiñoisinthewind393.2The2023NorthAtlantichurricaneseason:RecordhotAtlanticOceanversusElNiño434/ContactsandInformation46TABLEOFCONTENTS22ForewordRecentEventsOutlookContactsandInformation33ForewordForewordOutlookRecentEventsContactsandInformationWehopetoprovidenewperspectivesthatwillhelpwithnaturalcatastropheriskmanagementandresilienceinsectorssuchasinsurance,banking,government,andcorporatesacrossallindustries.Inthisedition,welookatsomeofthephysical,vulnerability,andsocio-economicfactorsthatcontributedtonaturaldisastersinthefirsthalfof2023.WealsoconsiderwhattherestoftheyearmightholdwithElNiño'sreturnandtheupcomingNorthAtlanticHurricaneseason.Thefirstsixmonthsof2023weredominatedbythedevastatingKahramanmaraşearthquakesinTürkiyeandSyriaandseveralweather-relatedcatastrophes.Arecord-breakingstarttotheU.S.tornadoseasonresultedinbillionsofdollarsindamage,whiletheongoingmegadroughtinChilebroughtdestructivewildfires.Canadaisalsoexperiencingitsworst-everwildfireseason,witharecord-breaking8.33millionhectaresdestroyedafteronlytwomonthsoftheMay–Septemberfireseason.CyclonesFreddie,Gabriele,andMochahadwide-rangingimpactsintheSouthernWelcometothelatestissueofWTW’sNaturalCatastropheReview,abi-annualpublicationthatbringsinsightsfromourexperts—includingourWTWResearchNetwork—toexaminerecentnaturaldisasters,lessonslearned,andemergingtrends.Hemisphere,andsignificantfloodingaffectedanumberofcountriesincludingItaly,Ethiopia,Somalia,Malaysia,Brazil,andNewZealand.Climatechangewillonceagainbeattheforefrontofbusinessandgovernmentagendasasaresultoftheseevents.However,itiscriticalnottoforgettherolesocio-economicfactorsplayindeterminingtheseverityofextremeweatheroutcomes.Naturalhazardsonlybecomedisasterswhentheyintersectwithaninadequatelypreparedsociety.KatrinawasadisasterbecauseunderlyingsocialinequalitiesinNewOrleansworsenedstormdamageandchallengeddisasterrecovery.ThewildfiresthatravagedChileinFebruarythisyearwereadisasterbecauseoftheintermixingofforestryplantationsandcommunities(Section2.5).InNewZealand,floodingWelcome441Smith,N.There'sNoSuchThingasaNaturalDisaster.UnderstandingKatrina:perspectivesfromthesocialsciences11,(2006).Itisnearly20yearssinceNeilSmith–whowasaDistinguishedProfessorofAnthropologyandGeography–publishedhisseminalessayThere’sNoSuchThingasaNaturalDisaster1.ThiswaswrittenintheaftermathofHurricaneKatrinaandinitiatedaconversationonhowwethinkaboutnaturalcatastrophes.ForewordOutlookRecentEventsContactsandInformation55followingCycloneGabrielewasexacerbatedbydebrisfromforestryactivitythatcloggedriversanddestroyedbuildingsandinfrastructure(Section2.4).AndtherecentdevastationinItaly’sEmilia-Romagnaregionfromfloodingwasworsenedbyland-usechange(Section2.8).Ifwearetoimproveresilienceinawarmingworld,wemustthereforelooknotonlyathowthefrequencyandseverityofextremeweathereventsarechanging,butalsoathowinteractionsbetweenhazardsandsocietyarechangingtoo.InNewZealand,thereisaconcertedeffortto“buildbackbetter”followingthesecondwettestsummeronrecord.Thisrequiresaholisticapproachthatconsidersthephysical,social,andeconomicaspectsofaffectedcommunities2,aswellasinvestmentinriskmanagementresearchtoinformdecision-making.LateralthinkingonearthquakeriskInFebruary,thelargestearthquaketohitTürkiyeinnearlyacenturykilledover50,000peopleanddestroyedthousandsofbuildings.Whenamajordisasteroccurs,thereareoftenlessonstobelearnedthatwillhelpusbuildbackbetter.Forexample,followingthe1999Mw7.6IzmitearthquakeinnorthernTürkiye,newbuildingregulationsandanationalinsurancepoolwereputinplacetoimproveresilience.Aslessonsbegintoemergefromthemostrecentevent,wemustremembertothinklaterallytoimproveriskmanagement,particularlyinotherpartsoftheworldwhererecentobservationsarelacking.InSection2.1,Temblor'sRossSteinexaminesthelessonsfromTürkiyethatcanbeappliedtoCalifornia,includingthepossibilityoflargeeventsonsecondaryfaults,interactingmainshocksthatattackbuildingstwice,andthelikelihoodofextremeshakingneartheruptureandindeepbasins.PropertymarkettippingpointsInrecentyears,therehasbeenanincreasedfocusonsocio-economictippingpoints,wheregradualchangesintheclimatesystemcouldresultinabruptchangestosocio-economicsystems3.AnexampleisHawke'sBay,aregionontheeastcoastofNewZealand'sNorthIsland,whichisoneofthecountry'smostdesirablelocationsforcoastalliving.InFebruary,CycloneGabriellebroughtdestructiontotheNorthIsland,withrecord-breakingwindsandfloodingthatdestroyedhouses,infrastructure,andcrops.InSection2.4,NeilGunndiscussestheimpactsofGabrielleandlooksatrecentresearchthatsuggestsHawke'sBayisapproachingasocio-economictippingpoint,wherelossesfromthegradualincreaseinextremeweathereventscouldleadtothecollapseofpropertyprices.2Mannakkara,S.,Wilkinson,S.&Potangaroa,R.Resilientpostdisasterrecoverythroughbuildingbackbetter.(Routledge,2018).3Ginkel,K.C.H.vanetal.Climatechangeinducedsocio-economictippingpoints:reviewandstakeholderconsultationforpolicyrelevantresearch.Environ.Res.Lett.15,023001(2020).FiveCategory5stormsinfivemonthsIntensetropicalcyclonesduringtheearlymonthsoftheyeararerare.Onaverage,therehavebeen1.1Category5equivalentstormsbetweenJanuaryandMaysince1980.However,thisyearhasbeenunusual,withfiveeventsinthefirstfivemonths:Freddy,Kevin,Isla,Mocha,andMawar.InSection2.3,wereviewhowseveralofthesestormshavebrokenindividualrecords,mostnotablyFreddy,whichproducedthehighestAccumulatedCycloneEnergyeverrecordedworldwide.Withglobalseasurfacetemperaturescurrentlyatall-timehighssincesatelliterecordsbegan,theattentionwillnowturntotheupcomingNorthAtlanticandWesternPacificseasonstoseeifthetrendcontinues.ThelargestnumberofCategory5equivalenttropicalcycloneseverrecordedinacalendaryearis12in1997.Whenthewinddoesn’tblowWhilethefocusisoftenplacedonlearninglessonsfromlargenaturaldisasters–suchastherecentearthquakesinTürkiye–itisequallyimportanttoconsiderwhatwecanlearnwhencatastrophesdon’thappen.Forexample,understandingthefactorsthatcontributetothevariabilityinextremeweather–includingquiescentperiods–isimportantforplanningandriskmanagementinindustriessuchasinsuranceandagriculture.InSection2.9,AdamScaifeandcolleaguesfromtheUniversityofExeterinvestigatewhythereweresofewEuropeanwindstormsduringthewinterof2022/2023andwhythiswasnotentirelypredictedbyseasonalforecastmodels.ForewordOutlookRecentEventsContactsandInformation66ElNiño’sreturnForthreeyearsinarow,thePacificOceanhasbeenstuckinitsLaNiñaconfiguration,producingwhatisknownasa“tripledip”event.LaNiñaisusuallyassociatedwithcatastrophicfloodinginAustralia–aswewitnessedin2022–andbusyNorthAtlantichurricaneseasons,suchastherecord-breakingyearin2020.ButnowthePacifichasflippedtoElNiño,withtheU.S.NationalOceanicandAtmosphericAdministrationdeclaringitsarrivalonJune8.InSection3.1,ScottSt.Georgewritesaboutthemeteorologicalandsocio-economiceffectsthatbusinessesshouldexpectfromanElNiñoevent.JamesDonefromtheNationalCentreforAtmosphericResearch(NCAR)thenreviewswhatthismeansfortheupcomingNorthAtlantichurricaneseasoninSection3.2.Aswebegintoprocessthelessonslearnedfromthesemostrecenteventsandincorporatenewknowledgeintoriskmodels,itisimportanttorememberthatpreparednessandresiliencerequiremorethanjustbettermodels.Wemustalsoconsiderhowourmodels,withalltheirsimplifications,canbebestusedtoinformreal-worlddecision-making.ForewordOutlookRecentEventsContactsandInformation77RecentEventsForewordOutlookRecentEventsContactsandInformation88Theearthquakestookthelivesof53,000people,left2millionpeoplehomeless,andwillcostanestimated$34billiontorecoverfromthedamage.AmongthemanytragicandalarmingelementsoftheTürkiyeearthquakesaresomethatcouldbefallCalifornia.Theseincludethepossibilityofgreateventsonsecondaryfaults,interactingmainshocksthatimpactbuildingstwice,andthelikelihoodofextremeshakingneartheruptureandindeepbasins.2.1Worldsapart:Implicationsofthe2023Mw7.8andMw7.5Kahramanmaraş,Türkiye,earthquakesforCaliforniabyRossS.Stein,VolkanSevilgen,AliÖzbakir,ShinjiTodaandHectorGonzales-HuizarProgressivemainshocksandearthquakeinteractionOn6FebruaryaMw7.8earthquakestrucksouthernandcentralTürkiyeandnorthernandwesternSyria,followedbyaMw7.5shockonadifferentfault9hourslaterand100kmaway.Surelythisisrare.No,itisnot.Seismologistsliketellingusthatthelargestaftershockisaboutonemagnitudeunitsmallerthanthemainshock,butearthquakesdon’tfollowourrules;instead,theyareoftenpartofachainreaction.Examplesaboundofmainshocksstrikingwithinhourstomonthsofeachother,includingthe1811-1812Mw7.2,7.0,7.4NewMadrid,Missouri,quakesseveralmonthsapart;the1992Mw7.3LandersandMw6.5BigBear,California,shocks3hoursapart;the2002Mw6.6andMw7.9Denali,Alaska,quakes10daysapart,andthe2019Mw6.4andMw7.1Ridgecrest,California,quakes31hoursapart1.Infactprogressiveorcompoundmainshocksarenotrestrictedtoanyregionortectonicsetting.1Toda,S.&Stein,R.S.Longandshort-termstressinteractionofthe2019RidgecrestsequenceandCoulomb-basedearthquakeforecast.BulletinoftheSeismologicalSocietyofAmerica110,1765–1780(2020).ForewordOutlookRecentEventsContactsandInformation99Figure1.CoulombstressimpartedbytheMw7.8rupturetotheCardak-SürgüFaults,whichwouldrupture9hourslater.Stresspromotingfailure(redpatches)isconcentratednearwheretheMw7.5nucleated,whichsuggeststhatthefirstshockpromotedortriggeredthesecond.FromSteinetal.(2023)2.Source:Temblor3Lacoletti,S.,Cremen,G.&Galasso,C.Modelingdamageaccumulationduringground-motionsequencesforportfolioseismiclossassessments.SoilDynamicsandEarthquakeEngineering168,107821(2023)2Stein,R.S.,Toda,S.,Özbakir,A.D.,Sevilgen,V.,Gonzalez-Huizar,H.,Lotto,G.,Sevilgen,S.2023,Interactions,stresschanges,mysteries,andpartialforecastsofthe2023Kahramanmaraş,Türkiye,earthquakes.Temblor.http://doi.org/10.32858/temblor.299(2023)Therearetwoimplicationsofearthquakeinteraction:12Thegoodnewsisthatbycalculatingthe‘Coulombstress’transferredbyamainshocktothesurroundingregion,onecanidentifythefaultsbroughtclosertofailure,andthosebroughtfartherfromfailure(Figure1).Insomeplaces,thehazardrises;inothers,itdrops.ThisiswhatTemblor’sRealtimeRisktechnology(whosedevelopmentwassupportedbytheWTWResearchNetwork),does:oncealargequakestrikes,thehazardchanges,whichmodelsneedtocapturesothatnextyear'sriskisreflectedinmodels.Thisisincontrasttoconventionalearthquakeriskmodels,whichdonottakestressinteractionintoconsideration.Thebadnewsisthatbuildingsdamagedinthefirstshockcancollapseinthesecond,whichthe‘hoursclause’ininsurancecontractsdoesapoorjobofaccountingfor.ThinkofthemanyhorrifyingbuildingcollapsevideosoftheTürkiyequakewesaw,filmedindaylight.Thefirstquakestruckinthedark,at4amlocaltime,andsomostofthevideoedcollapsesoccurredduringthesecondshock,withthebuildingssuccumbingtoa‘one-twopunch.’Tryingtoaccountforthisdynamicaccumulationofdamageinfragilityandvulnerabilitymodelsisanactiveareaofresearch3.ForewordOutlookRecentEventsContactsandInformation1010Figure2.Thereareabout25observations(red)ofPeakGroundAcceleration(PGA)exceeding0.5g.Atthislevelofshaking,allbutthemostresilientbuildingsgenerallysufferstructuraldamage.TheTemblorGroundMotionModel(blue)doesagoodjobofcapturingthisshakingatdistancesof10-400kmfromthefaultrupture.Source:Temblor4Erdik,M.,Tümsa,M.B.D.,Pınar,A.,Altunel,E.,andZülfikar,A.C.ApreliminaryreportontheFebruary6,2023earthquakesinTürkiye.Temblor.http://doi.org/10.32858/temblor.297(2023).5Yeginsu,C.,Ruiz,R.&Kirac,N.Earthquake-Proof,NotCorruption-Proof:Turkey'sNeedlessDeaths,NewYorkTimes,4Mayedition,https://www.nytimes.com/2023/05/04/world/europe/turkey-earthquake-corruption.html(2023).6Statisticsfromthe9May2023EarthquakeEngineeringResearchInstitute(EERI)‘LearningFromEarthquakes’webinar.ExtremeshakingclosetothefaultruptureIthasbeenwidelyreportedthatcollusionbetweenbuildersandinspectors,andcodecomplianceamnestiesissuedbythegovernment4,5,werethelargestcontributorstothe35,000buildingcollapses,theadditional18,000slatedfordemolition,andthe180,000buildingsheavilydamaged6.Butthatisnotthewholestory.Thesadtruthisthatshakingatfrequenciesthatattack6-10-storybuildings,whichtypifymanycities,oftenexceededthemoststringentbuildingcoderequirementinTürkiye(the‘2%in50-year’groundmotion,whichtranslatesintoa2500-yearreturntime)4.TheMw7.8Kahramanmaraşeventisbyfarthebest-recordedearthquaketheworldhaseverknown.AlthoughJapan’sstrongmotionnetworkisunrivaled,andthe2011Mw9.0Tohokushockwasmuchlarger,themegathrusteventstruck80kmoffshore.Incontrast,thereareabout50stationswithin25kmofthe2023rupture,sevenofwhichrecordedPeakGroundAccelerations(PGA)inexcessof1g(Figure2).Thisextremenear-faultshakingwouldlikelyoccurduringquakesofsimilarsizeinCalifornia,suchasontheSanAndreasorHaywardFaults.Butuntilnow,therewaslittleornodatatoanticipatesuchshaking.Thismeansbuildingsclosetotherupturecouldfareworsethanexpectedincurrentmodels,andthatU.S.buildingcodesmayneedrevisiontoaccountforthiseffect.ForewordOutlookRecentEventsContactsandInformation1111Figure3.Collapsedbuildingstendtobeconcentratedinregionsmodeledtohavehighsiteamplification.TheTemblorSTAMPmodelisbasedonfeaturesoftherelief,inwhichflatareasarelikelysedimentarybasins(orange),andareaswithmorereliefaresitesofbedrock(blue).Source:Temblor7HumanitarianOpenStreetMapTeam,HOTOSMTurkeyDestroyedBuildings(OpenStreetMapExport),https://data.humdata.org/dataset/hotosm_tur_destroyed_buildings(2023).BuildingcollapsesconcentratedinareasofhighsiteamplificationTheinventoryofcollapsedTurkishbuildings,compiledfromsatelliteimagery(HumanitarianOpenStreetMapTeam,2023)7,furnishesanunmatcheddatasettostudycollapse.Thisscientificgiftcameataterriblecost,sowemustuseitwisely.Ourpreliminaryanalysisrevealsthatcollapseishighlycorrelatedwithsiteamplification,asseeninthe100mresolutionTemblormodel,STAMP(Figure3).Thecollapserateinflatareasunderlainbysoftsedimentsismuchhigherthanelsewhere.Becausenearlyidenticalbuildingslikelybuiltatthesametimebythesamebuilderspanregionswithhighandlowsiteamplification,wecanoftencontrolforotherfactors,andconcludethatsiteamplificationisofprimaryimportanceinassessingrisk.Incontrast,whileliquefactionandlandslidesoccurred,theywerelessinfluentialforcollapse.ForewordOutlookRecentEventsContactsandInformation1212Figure4.ComparingfaultsinTurkey(toppanel)andCalifornia(bottompanel)revealsmanysimilaritiesintermsoffaultstraightness,length,andsliprate.Noticethatthemapscalesaredifferent.OminoussimilaritiesbetweenfaultsinEasternTürkiyeandCaliforniaTheNorthAnatolianandSanAndreasFaultsareremarkablysimilarinlength,sliprateandearthquakehistory(Figure4);bothhaveexperiencedMw7.8shocksinthepast170years8.TheEastAnatolianFaultresemblestheHayward-RodgersCreekFaultinnorthernCalifornia,theSanGregorioalongthecentralcoast,theOwensValley-InyoFaultineasternCalifornia,andtheSanJacintoinsouthernCalifornia.So,thosefaultsshouldhaveMw7.8shocksinanystochasticeventsetoneisusing.TheCardak-SürgüFaultcloselyresemblestheGarlockFaultinsouthernCalifornia.Botharesomisalignedforthetectonicstressesthattheymustbeveryslipperytomoveatall.Butdespitethatmisalignment,weshouldassumethattheGarlockFault,whichabutstheSanAndreas,iscapableofaMw≥7.5event.ThemostimportantlessonisthattheTürkiyequakesdidnotstrikeontheequivalentofthemightySanAndreasFault,butinsteadonshorter,low-slip-ratefaultsthatareoftendeemedincapableofquakesofthisgreatsize.TheEastAnatolianFaultis600kmlongwithasliprateof~10mm/yr,andtheCardak-SürgüFaultis200kmlongwithasliprateof~3mm/yr;bothcanbeconsideredpartofthebroadEastAnatolianFaultZone.TheMw7.8earthquakenucleatedontheminor,20-km-longNarlıFault,andthenjumpedontotheEastAnatolianFault,propagatinginbothdirections(SWandNE),ultimatelyattainingarupturelengthof300kmwith~4.5maverageslip.TheMw7.5shocknucleatedontheCardakFault,andalsorupturedinbothdirections.Totheeast,itjumpedontotheSource:Temblor8Emre,Ö.,Duman,T.Y.,Özalp,S.,Elmacı,H.,Olgun,Ş.andŞaroğlu,F.ActiveFaultMapofTurkeywithandExplanatoryText,GeneralDirectorateofMineralResearchandExploration,SpecialPublicationSeries-30.Ankara-Turkey.https://www.mta.gov.tr/en/maps/active-fault-1250000(2013).ForewordOutlookRecentEventsContactsandInformation1313SürgüFault,attaininga150-kmtotallengthand~7maverageslip.So,surprisingly,theslower,shorterfaulthadthehighestslip.Evenstranger,theCardak-SürgüFaultshouldn’tslipatall;itismisalignedforfailure.Itwasformerlya‘right-lateral’fault(whicheversideyouareon,theothersidemovestotheright)thatonlyrecentlybecameleft-lateral(thisswitchiscalled‘inversion’bygeologists).So,thekeyquestionis,arewepreparedforMw7.8andMw7.5shocksontheirCaliforniaequivalent?Theanswerisprobablyno,becausewe’vefocusedoneventswithrepeattimesof500yearsorless.Instead,Temblor’seventsetyieldsan1800-2000yearrepeattimeforquakesinthisZone.What’sessentialistoharnessthesehard-woninsightsfromTürkiyetobetterforecastseismicrisk,andbetterprepareforitsconsequencesinCaliforniaandelsewhere,wheremuchofwhatwehavejustwitnessedcanalsooccur.ForewordOutlookRecentEventsContactsandInformation14142.2IstherecordnumberofconvectivestormsinthefirstquarterasignofthingstocomeintheU.S.?byCameronRyeFollowingarecord-breakingfirstquarterforsevereconvectivestorms(SCS)intheUnitedStates,insurersandriskmanagersshouldconsiderwhethertheirviewofriskreflectstheevolvingpatternsofSCSactivity.RankTornadoCountYear147620232398201733602008429219995290201262822022724620078231197692122020102072006Thesehighnumberswerecausedbyaseriesofmulti-daytornadooutbreaksthatcaninpartbeattributedtothepresenceofLaNiña(whichoftenprovidesfavorableconditionsforspringtimeconvectiveactivity).ThemostnotableoutbreakoccurredattheendofMarch,affectingstatesintheMidwest,Southern,andEasternU.S.Atotalof134tornadoeswererecordedbetween7pmUTConMarch31stand7pmUTConApril1st,rankingthirdintheTable1.Top10yearswiththehighestJan–Marchtornadocounts.TornadocountispreliminaryandmaychangeoncethedataisfinalizedbytheStormPredictionCentre.Datasource:NationalWeatherServiceStormPredictionCentre.1Verbout,S.M.,Brooks,H.E.,Leslie,L.M.&Schultz,D.M.EvolutionoftheU.S.TornadoDatabase:1954–2003.WeatherandForecasting21,86–93(2006).worldforthehighestnumberofeventsreportedina24-hourperiod.Itwillalsobeoneofthemostexpensivefirstquartersonrecordforinsuredlossesfromconvectivestorms,withestimatesputtingclaimsintheregionof$7-10billionUSD.PrimaryinsurerswilllikelybearalargershareofthiscostthantheywouldhaveinprioryearsduetothehigherreinsuranceattachmentsandloweraggregatecoverageattheJanuary1strenewals.Convectiveactivitycontinuedintothesecondquarter,withmanysevereweatheroutbreaks,includingonethatdeliveredrecord-sizedhailandstrongwindsacrossCentralandSouthernstatesbetweenJune10andJune19.Insuranceclaimsarestilldeveloping,but2023isexpectedtorankhighonthelistofcostliestSCSyears.Lossesduetoconvectivestormshavebeenincreasingoverthepast20years,andthisstormystarttotheyearwillundoubtedlyincreasefurthertheinsuranceindustry'sconcernaboutthisperil.Alargeproportionoftheincreasecanbeattributedtopopulationgrowthandurbanization.Climatechangemayalsobeplayingsomerole,butthescienceisnotdefinitivebecausedetectingatrendinlocalizedphenomenasuchastornadoesisnotoriouslydifficult,especiallywhenmostofthehistoricalrecordisbasedprimarilyoneyewitnessanddamagereports1.TheyearhadbarelybegunwhentheUnitedStateswashitbyaseriesofdamagingsevereconvectivestorms.Therewere476tornadoesreportedbetweenJanuaryandMarch,accordingtopreliminarydatafromtheU.S.NationalWeatherServiceStormPredictionCentre.Thisearlyactivityhasmade2023theyearwiththemostfirst-quartertornadoesonrecord(Table1).ForewordOutlookRecentEventsContactsandInformation1515Recentresearchhasfoundthattornado-favorableenvironmentsduringwintertimehaveincreasedacrossthesouthernGreatPlainsandsoutheasternU.S.2.DatafromtheNationalWeatherServiceStormPredictionCentrealsoshowsasteadyincreaseinDecember–FebruaryU.S.tornadocountssince1990(Figure1).However,whileawarmingworldisexpectedtoleadtomilderwintersthatgeneratetheatmosphericinstabilitynecessaryforconvectivestorms,itisnotcleartheextenttowhichthisobservedtrendisduetoclimatechangeorotherfactorssuchasnaturalvariabilityandreportingbiases.Thereisstrongerevidencethatthegeographicpatternoftornadoesischanging.Since1979,thenumberofSCSeventsaffecting"TornadoAlley"intheGreatPlainshasdecreasedslightly,whileactivityhasincreasedineasternstatessuchasMississippi,Tennessee,Alabama,Illinois,andIndiana3.Thisshifthaspushedstormsintoareasthathaveseenrapidpopulationgrowthoverthelastfewdecades,increasingthelikelihoodoftornadoescausingpropertydamageandfatalities.Lookingfurtherintothefuture,arecenthigh-resolutionmodellingstudyhasfoundthatsupercells–stormsthatproducethestrongesttornadoesandareassociatedwiththemostsevereimpacts–areexpectedtooccurmorefrequentlyinawarmerworld4.Thispredictionincludesanincreaseinearly-seasonsupercells(aswesawthisyear),withanintermediatewarmingscenarioproducingupticksinFebruary(7%),March(18%),andApril(37%)bytheendofthecentury.Figure1.December-FebruarytornadocountsintheUnitedStatessince1990.Itisnotcleartheextenttowhichthisobservedtrendisduetoclimatechangeorotherfactorssuchasnaturalvariabilityandreportingbiases.0501001502002503001990199119921993199419951996199719981999200020012002200420052006200720082009201020112012201320142015201620172018201920202021202220232003Tornadocount2Taszarek,M.,Allen,J.T.,Brooks,H.E.,Pilguj,N.,&Czernecki,B.DifferingTrendsinUnitedStatesandEuropeanSevereThunderstormEnvironmentsinaWarmingClimate.BulletinoftheAmericanMeteorologicalSociety102,(2021).3Gensini,V.A.&Brooks,H.E.SpatialtrendsinUnitedStatestornadofrequency.npjClimateandAtmosphericScience1,1–5(2018).4Ashley,W.S.,Haberlie,A.M.&Gensini,V.A.TheFutureofSupercellsintheUnitedStates.BulletinoftheAmericanMeteorologicalSociety104,E1–E21(2023).Datasource:NationalWeatherServiceStormPredictionCentreWhilescientistsarestilltryingtofullyunderstandtheconnectionbetweentornadoesandclimatechange,insurers,aswellashomeandbusinessowners,continuetocountthecosts.Thistensionhighlightstheimportanceofensuringthatthepresent-dayviewofriskisadequatelyrepresentedininsurancecatastrophemodels,aswellasotherdecision-makingframeworkssuchasresilienceplanning.ForewordOutlookRecentEventsContactsandInformation16162.3AnunusuallylargenumberofCategory5tropicalcyclonesbyCameronRyeWithsomanyextremeweathereventsinthefirsthalfoftheyear,itwaseasytohaveoverlookedtheunusualtropicalcycloneactivitythatproducedfiveCategory5stormsinfivemonths.Category5equivalent1tropicalcyclonesarerare,withanaverageof4.7occurringperyearsince1980,accountingforlessthan10%ofalltropicalcyclonesglobally(Figure1).However,thisyearhasbeenunusual,withfiveeventsinthefirstfivemonths:Freddy,Kevin,Isla,Mocha,andMawar(Table1).Incomparison,anaverageof1.1eventshaveoccurredgloballybetweenJanuaryandMaysince1980.Theonlyrecentprecedentis2015,whensixCategory5stormshaddevelopedbytheendofMay.Thisyear'seventshavealsobrokenanumberofindividualrecords(Table1).VeryIntenseTropicalCycloneFreddyproducedanAccumulatedCycloneEnergy(ACE)of87–thehighestforatropicalcycloneonrecord.At35days,Freddymayalsohavebrokentherecordforthelongest-livedcyclone,althoughtheWorldMeteorologicalOrganisation(WMO)isstillverifyingthis.Thestorm'spowercausedsignificantdamagewhenitmadelandfallinMadagascarandMozambique,resultinginnearly1,450fatalities,makingitthethirddeadliestonrecordintheSouthernHemisphere.Figure1.TheglobalannualcountofCategory-5equivalenttropicalcyclones,1980-2022.Theannualaveragesince1980is4.7(dashedline).02468101214Category-5equivalenttropicalcyclonecount19801982198419861988199019921994199619982000200220042006200820102012201420162018202020221Definedassustained1-minutewindspeedsgreaterthanorequalto157mphaccordingtotheSaffir-Simpsonscale.Datasource:Knapp,K.R.etal.InternationalBestTrackArchiveforClimateStewardship(IBTrACS)Project,Version4-since1980.NOAANationalCentersforEnvironmentalInformation(2018).ForewordOutlookRecentEventsContactsandInformation1717SevereTropicalCycloneIlsamadelandfallinWesternAustraliainAprilasaCategory5stormnortheastofPortHedland.OnBedoutIsland,a10-minutesustainedwindspeedof136mphwasmeasured,breakingthepreviousAustralianrecordforalandfallingstormsetbyCycloneGeorgein2007.Becausethestormavoidedpopulatedareas,includingtheworld'slargestironoreexporthubinPortHeadland,economicandinsurancelosseswereminimal.InearlyMay,ExtremelySevereCyclonicStormMochabecametheNorthIndianOcean'sjointstrongesttropicalcyclone,witha1-minutesustainedwindspeedof175mph.ThecyclonemadelandfallinMyanmar,abouttenmilesnorthwestofSittwe,theregionalcapitalofRakhinestate.Giventhestorm'sproximitytotheworld'slargestrefugeecampinCox'sBazar,Bangladesh,therewerefearsofsignificantcasualtiespriortolandfall.However,authoritiesandaidorganizationswereabletoevacuatehundredsofthousandsofpeopleinMyanmarandBangladeshaheadoftheevent,mitigatingthehumanitarianimpact.Afewweekslater,SuperTyphoonMawarbecamethemostpowerfulstormof2023sofar,withsustained1-minutewindsof185mph.Thecyclonebroketworecords:thehighestACEandthejoint-highest1-minutesustainedwindspeedobservedinthemonthofMay.Theonlyotherstormtoreach185mphinMayisTyphoonPhyillisin1958.MawarpassednorthofGuam,bringingheavyrainandstrongwindstotheisland,makingitthestrongesttyphoontoaffecttheU.S.territoryinovertwodecades.2ClimateReanalyzer.UniversityofMaine.https://climatereanalyzer.org/clim/sst_daily/(2023)Table1.Category5equivalenttropicalcyclonesJan-May2023.NameRegionsAffectedGenesisDateWindSpeed(mph)RecordBrokenFreddyMadagascar,Mozambique5February165Highest-ACE-producingtropicalcycloneeverrecordedKevinSolomonIslands,Vanuatu26February160—IlsaWesternAustralia6April160Strongest10-minutesustainedwindspeedatlandfallinAustraliaMochaMyanmar,Bangladesh8May175Jointhighest1-minutesustainedwindspeedintheNorthIndianOceanMawarGuam,Philippines,Taiwan,Japan17May185HighestACEandjointhighest1-minutesustainedwindspeedinMay1-minutesustainedwindspeedFreddyandMochahighlightedthatthereisstillaconsiderableprotectiongapinmanytropicalcyclone-pronecountries,witheconomiclossesfarexceedinginsurancecoverage.Byprovidingpre-determinedandfasterpay-outstofundemergencyresponseandspeeduprecovery,parametric(orindex-based)insuranceisseenasoneoptionforimprovingresiliencetotheimpactsofthesetypesofevents.Forexample,WTWrecentlydesignedaparametricinsuranceproductforUNICEF'sTodayandTomorrowInitiative,whichwasfundedbythegovernmentsoftheUnitedKingdomandGermany.TheparametricindexcombinestropicalstormwindspeedsmodelledbyKineticAnalysisCorporation,withchildpopulationdistributiontocaptureimpactsonvulnerablepopulations.TheprogramcoverschildrenandfamiliesineightUNICEFhostcountriesthatarevulnerabletotropicalcyclones:Bangladesh,Comoros,Haiti,Fiji,Madagascar,Mozambique,SolomonIslands,andVanuatu.Scientistswillmostlikelyneedsometimetodissectthereasonsfortheincreaseinearly-seasonactivitythisyear.Globalseasurfacetemperaturesinthefirsthalfof2023havebeenatall-timehighssincesatelliterecordsbegan2,whichmayhaveplayedarole.Butfornow,alleyeswillbeontheupcomingNorthAtlantic(Section3.2)andWesternPacificseasonstoseeifthetrendcontinues.ThelargestnumberofCategory5stormseverrecordedinacalendaryearis12in1997,sothereisstillsomewaytogotobreakthisrecord.ForewordOutlookRecentEventsContactsandInformation18182.4BuildingbackbetterfollowingtropicalcycloneGabriellebyNeilGunnFollowingarecord-breakingstorminNewZealand,callshavebeenmadeforthecountrytobuildbackbettertoimproveresiliencetoclimatechangeandmitigatetherisksfromforestrywaste.NewZealanddeclaredonlyitsthird-evernationalstateofemergencyinFebruaryfollowingCycloneGabrielle,whichdamagedproperty,infrastructureandcropsacrosstheNorthIsland.ThegovernmentestimatedthateconomiclossesfromtheeventwillbeatleastNZ$13.5billion($8.4billion),secondonlytothe2011Christchurchearthquake.AccordingtoPERILSAG,insuranceclaimscurrentlystandataroundNZ$2billion(U.S.$1.3billion).GabrielleformedasatropicallowoffthecoastoftheSolomonIslandsonFebruary5,beforemovingsouthacrosstheCoralSeaandstrengtheningintoaCategory3tropicalcyclone.AsthestormapproachedNewZealand,itweakenedandunderwentextratropicaltransition,unleashingheavyrainandstrongwindsontheNorthIslandforthreedaysbetweenFebruary12and14.SeveralmeteorologicalstationsinNewZealandsawrecordornear-recordsummerwindgusts,whilestormsurgelevelspeakedat0.7m,accordingtotheNationalInstituteofWaterandAtmosphericResearch(NIWA).Themostdamagingfeatureofthestormwasheavyrainfall,withNIWAreportingrecordornear-recordtotalsacrossmuchoftheNorthIsland,particularlyontheEastCoastaroundGisborneandHawke’sBay.Therainlandedonalreadysaturatedground.Thesummerof2022/2023wasthesecondwettestonNIWA’srecordsfortheNorthIsland,andonlyafewweeksearlierCycloneHalecaused1-in-200yearfloodinginAuckland.Asaresult,theriversrespondedswiftlytoGabrielle’sprecipitation.Newhigh-flowrecordswereset,withmanygaugingstationsjudgedtobeinexcessofa1-in-500yearreturnperiods1.OntheRiverEsk,familiesreportedhavingtoclimboutofthewindowsoftheirpropertiestoawaitrescueontheirroofs,withsomeestimatingthatwaterlevelsroseby3metersinjust10minutes.NewZealand’slandscapeissteepanddynamic.Theheavyrainscausedmanylandslides,underminingorburyingmajorroadsincludingseveralstatehighways.Thecombinationoflandslidesandhighwindsalsocutpower,watersupplies,andcommunications.Theoutagesweresustainedforseveraldayswidelyandweeksinsomelocations.Manyofthetelecommunicationsystemswereexposedtosinglepointsoffailure,whichmadeincidentmanagementandrecoverymoredifficultthanitshouldhavebeen.1PersonalCommunication,AshtonEaves,Hawke’sBayRegionalCouncil.ForewordOutlookRecentEventsContactsandInformation1919TheroleofforestrywasteLargewoodydebrisfromforestryoperations,knownlocallyasslash,contributedtotheseverityoftheeventbycloggingriversanddestroyingbuildingsandinfrastructure(Figure1).Historicforestrypolicyledtothereplacementofnativetreespecieswithpineplantationsonmuchoftheeasterncoast.Siltandslashfromtheseplantationswashedintotheriversystemandaccumulatedaroundbridges.ThisledtothedestructionofbridgesandovertoppingofdefensesduringGabrielle.OntheTutaekuriRiveralonetherewere5.3kmofbreachesand25.5kmofweakenedbanks,accordingtoHawke’sBayRegionalCouncil.Alongwithrainfallintensityandamount,thishelpstoaccountforveryrapidratesofriseoffloodwater.2MinisterialInquiryintoLandUsesinTairawhitiandWairoa.OutragetoOptimism.https://environment.govt.nz/assets/Outrage-to-Optimism-CORRECTED-17.05.pdf(2023).Figure1.Top:forestrydebrispileduponarailwaybridgeovertheRiverEsk.Notethedebrisattachedtothetopofthebridgeshowsthemagnitudeofexceedanceofdesignstandards.Bottom:extensivesiltdepositiononthelowerreachesofriversdevastatedfarmlandandinfrastructure,recoverywilltakeyearsSoilscientistsestimatethatthecountryhas5-10yearstochangelandusetoprotectsoilsontheforestedslopesoftheEastCoast2.©Stuff©StuffForewordOutlookRecentEventsContactsandInformation2020Climatechangeandsocio-economictippingpointsAtthesametime,NewZealandmustfindawaytodealwiththegrowingsocio-economicconsequencesofmorefrequentweatherdisasters.Insuranceclaimsfromatmosphericperilshaveincreasedoverthelastdecade,affectingtheavailabilityandpriceofpropertyinsurance(Figure2).Theproblemhasbeenexacerbatedbygrowingconcernsaroundtheeffectsoffutureclimatechange,whichwillnothavebeenalleviatedbyarapidattributionstudythatfoundGabrielle’srainfallwaslikelymade30%moreintenseduetohuman-inducedwarming3.Arecentstudy–fundedbytheNewZealandMinistryforBusinessInnovationandEmployment–exploredtheeffectsofextremeweatheronthepropertymarketinHawke'sBay4,whichisoneofthecountry'smostdesirablelocationsforcoastalliving.TheresearchersfoundthatthelocalcommunityislikelytoaccepttheFigure2.NewZealandweather-relatedinsuredlosses,adjustedforinflation.05010015020025030035040020122013201420152016201720182019202020212022InsuredLoss(2022NZ$m)3WorldWeatherAttribution.TheroleofclimatechangeinextremerainfallassociatedwithCycloneGabrielleoverAotearoaNewZealand’sEastCoast.https://www.worldweatherattribution.org/the-role-ofclimate-change-in-extreme-rainfall-associated-with-cyclone-gabrielle-over-aotearoa-new-zealands-east-coast(2023).4Eaves,A.,Kench,P.,McDonald,G.,Dickson,M.,&Storey,B.Modellingeconomicrisktosea-levelriseandstormsatthecoastalmargin.JournalofFloodRiskManagement,e12903(2023).Datasource:InsuranceCouncilofNewZealand.Researchintothesocio-economiceffectsofclimatechangeisincreasinglyfindingthatgradualphysicalchangesmaytriggerlargenon-linearresponsesinsocio-economicsystems.riskoffinanciallossandinsurabilityinexchangeforcoastallivingintheshort(1-10years)andmedium(10-20years)term.However,long-term(+20years)economiclossesfromrepeatedstormsandfloodingwilllikelyleadtoanincreaseininsurancepremiumsand,eventually,thecollapseoftheinsurancemarket,puttingdownwardpressureonpropertyprices.ForewordOutlookRecentEventsContactsandInformation2121BuildingbackbetterOverall,Gabriellehighlightsthatinachangingenvironmentitisimportanttotakeaholisticapproachtonaturalhazardriskmanagementthatconsidersnotjustclimatechange,butalsootherfactorsthatcancompounddisasterssuchasforestrymanagementandengineeringdesign.5InsuranceCouncilofNewZealand.NewZealandMustBuildBackBetter.https://www.icnz.org.nz/industry/media-releases/new-zealand-must-build-back-better/(2023).Stepsarebeingtakentoaddressthesechallenges.PrimeMinisterChrisHipkinsandTheInsuranceCouncilofNewZealandhavecalledforthecountrytobuildbackbettertoimproveresilience5,whileNZ$6billionhasalreadybeenallocatedtoaidrecoveryeffortsandimproveresilienceoverall,especiallyofroadsandtelecommunications.TheNationalAdaptationActandNaturalEnvironmentActarealsoindraft,whichcontainprovisionstoreducerisksfromnaturalhazardsasaconditionofrebuilding.ForewordOutlookRecentEventsContactsandInformation22222.5Countingthecostsofclimateandland-usechangeaftertheChileanWildfiresbyCameronRyeWildfiresravagedsouth-centralChileinFebruary,affectingtheMaule,Biobio,Ñuble,andAraucaniaregions.Followingsimilarfiresin2017,thereisgrowingconcerninthecountryaboutthedeadlycombinationofclimateandland-usechange.CentralChilehasbeenexperiencingamegadroughtsince2010,makingitoneofthelongestperiodsofdryweatherinthelast1,000years1.Wateravailabilityandvegetationhavesuffered,resultinginanumberofdestructiveforestfires.Sevenofthetoptenwildfireyearsonrecordhavenowoccurredsince2010,highlightingtheseverityofthesituation(Table1).ThemostrecenteventbeganonJanuary30,duringthesummerseasonintheSouthernHemisphere.Recordtemperaturesofover40°C,combinedwithstrongwinds,createdidealfire-spreadingconditions.Thisledtomorethan400individualfiresburningacrosssouth-centralChilebyearlyFebruary.Approximately430,000hectareswereburned(Figure1),resultingin26fatalitiesandover4,000damagedordestroyedbuildings,accordingtoChile'sdisasterresponseagency,SENAPRED.Table1.Top10worstfireyearsbyburnedareasince1964.RankBurnedArea(hectares,thousands)Year157020172430202331292015412520225106201461022020710219998971987991199810902012Datasource:Chile'sNationalForestCorporation(CONAF).Thismakes2023thesecondworstfireyearonrecord,after2017,when570,000hectaresofcentralandsouthernChilewereaffected.Likethisyear,theunderlyingdroughtconditionsin2017combinedwithhightemperaturesandwinds,resultingindisastrousFigure1.BurnedareafromtheFebruary2023wildfiresinsouth-centralChile.consequences.However,thisisonlyhalfofthestory;in2020,Chile'sCentreforClimateandResilienceSciences(CR)2issuedareportrecommendingincreasedregulationoftheforestryindustryinorderforthecountrytobecomemoreresilienttotheeffectsofclimatechange2.1Garreaud,R.D.etal.TheCentralChileMegaDrought(2010–2018):Aclimatedynamicsperspective.InternationalJournalofClimatology40,421–439(2020).2CenterforClimateandResilienceResearch-CR2.ForestfiresinChile:Causes,impactsandresilience.https://www.cr2.cl/eng/forest-fires-in-chile-causes-impacts-and-resilience/(2020).Source:NASA'sEarthObservatoryForewordOutlookRecentEventsContactsandInformation2323ForestryisbigbusinessinChile,accountingfor3%ofthecountry'sGDP,andtimberisthesecond-largestexportcommodityafterminerals.Expansiveplantationsoffast-growingspecies(primarilypineandeucalyptus)haveincreasedfrom300,000hectaresinthe1970stoover3millionhectarestoday.Previousgovernmentsencouragedthisexpansionbyallowingtheprivatisationoflargeareasofpubliclandandprovidingsubsidiesandtaxbreaksforplantations.Theproblemisthatnon-nativepineandeucalyptusspeciescontainoilsandresinsintheirleavesthatcaneasilyignitewhendry.Researchhasalsofoundthatbecauseplantationsareoftencompositionallyhomogenouswithfewfirebreaks,itpromotesgreaterfirespreadcomparedtonativedeciduousforests3.This,combinedwiththerecentdrought,hascreatedaperfectstormthathasproveddifficulttocontrol.However,climatechangeisexpectedtoplayanincreasedroleinwildfireriskoverthecomingdecades.Projectionsforthe21st-centuryindicateariseintemperaturesandareductioninprecipitationthroughoutChile,whichmodellingstudiessuggestwillleadtoanincreasedoccurrenceoflargefires4.Central-SouthChileisparticularlyvulnerablebecauseitcontainsnearly90%ofthecountry’splantations,and3millionpeoplelivewithinthewildland-urbaninterface5.(CR)2saysthatifthegovernmentistoreducetheriskfacedbyitspeople,decision-makersneedtomoveawayfromreactivemeasuresfocusedonfiresuppression,towardsactionsthattargetthesourceoftheproblem.Thisincludesbetterlandscapemanagement,establishingsafetyperimetersaroundurbanareas,andnewlawstopreventunsafepracticessuchastheexpansionofhomesintoforestedregions2.3McWethy,D.B.etal.Landscapedriversofrecentfireactivity(2001-2017)insouth-centralChile.PLOSONE13,e0201195(2018).4Ciocca,I.etal.IncreasedwildfirehazardalongSouth-CentralChileundertheRCP8.5scenarioasrevealedbyhigh-resolutionmodeling.Environ.Res.Lett.18,034023(2023).5Sarricolea,P.etal.RecentwildfiresinCentralChile:Detectinglinksbetweenburnedareasandpopulationexposureinthewildlandurbaninterface.ScienceofTheTotalEnvironment706,135894(2020).Accordingtoscientists,themegadroughtismostlikelytheresultofbothnaturalvariabilityandhuman-inducedclimatechange1.ForewordOutlookRecentEventsContactsandInformation24242.6Outofthewoods:HowfarwillCanada’swildfiresspread?byDanielBannisterCanada's2023wildfireseasonisofficiallyitsworstonrecord.AsofJuly2,thetotalburnedareahassurpassed8.33millionhectares,breakingthepreviousrecordforthelargestareaburnedinasingleyear.UnprecedentedMagnitudeCanada's2023wildfireseasonmadehistoryonJune30,bysurpassingthepreviousrecordof8.02millionhectaresofburnedareainasingleseason,setin1989(Figure1).Thisareawasreachedafteronly60daysoftheMay–Septemberfireseason,whichisinstarkcontrastto1989,whichtook153daystoreachthesameareaofdestruction.ThesewildfireshaveaffectednearlyeveryprovinceandterritoryinCanada,withonlyPrinceEdwardIslandandNunavutbeingspared.Outofthenumerouswildfires,justfourfiresaccountforone-quarterofthetotalburnedareareportedsofar1.Infact,thecombinedarea(2.35millionhectares)affectedbythesefourfiresexceedsthetotalburnedarearecordedattheendofthefireseasonin46outofthepast64years.Notably,theDonnieCreekfireinBritishColumbia,thesecondlargestamongthesefourfires,hasbecomethelargestfireeverrecordedintheprovince,spanninganareaof571,000hectares1.1CanadianWildlandFireInformationSystem.https://cwfis.cfs.nrcan.gc.ca/home(2023).2Hanes,C.C.etal.Fire-regimechangesinCanadaoverthelasthalfcentury.CanadianJournalofForestResearch49,256–269(2019).Figure1.EstimatedannualburnedareainCanada,1959-2023.012345678919601989Year8.02millionhectares197019801990200020102020July2,20238.33millionhectaresAreaburned(millionsofhectares)Datasource:Hanesetal.,20192(1959–2002),CanadianWildlandFireInformationSystem1(2003–2023).Lastupdated:July2,2023ForewordOutlookRecentEventsContactsandInformation2525Whilethefiresarepredominantlyoccurringinremoteareas,andCanadahashadlargefiresinthepast2,thetimingandwidespreadnatureoftheburningthisyearishighlyunusual.Thescaleofthisyear’sfiresissolargethattheburnedareaasofJuly2(8.33millionhectares)isequivalentinsizetocountriessuchasCzechiaandAustria(Figure2).UnusualCharacteristicsWhenlookingathistoricaldailydatafromtheCanadianWildlandFireInformationSystemforthelast20years(2003-2023)1,theunusualcharacteristicsofthecurrentwildfiresareclear.Theburnedarea(Figure2),number(Figure3),andlocation(Figure4)ofthefireshavealldeviatedfrompreviousyears,making2023unparalleledinrecenthistory.Onestrikingaspectistheearlyonsetoftheburning,whichcaughtmanybysurpriseasitoccurredbeforetheusualfavorableweatherconditionsforwidespreadblazes3.Figure2andFigure3illustratehowthefiresstartedmuchearlierthaninpreviousyears,withMay2023experiencingarecord-breakingnumberofnearly70,000individuallydetectedhotspots.TheburnedareaattheendofMaythisyear—amountingto2.8millionhectares—islargerthantheendofMayburnedareaforallyearscombinedoverthelastdecade(2012–2022).OnMay5alone,theburnedareawitnessedasixfoldincreasecomparedtothepreviousday,highlightingtherapidrateofspread.Almosteveryprovinceandterritoryhaveexperiencedrecordlevelsofburnedareaforthistimeofyear,withQuebec,Saskatchewan,BritishColumbia,andNovaScotiabeingparticularlyhardhit(Figure4).AsofJuly2,theseprovinceshadburnedareasaround180%largerthanthe20-yearaverageforthesametimeperiod.2Hanes,C.C.etal.Fire-regimechangesinCanadaoverthelasthalfcentury.CanadianJournalofForestResearch49,256–269.(2019).3Owens,B.WhyaretheCanadianwildfiressobadthisyear?NatureNews.https://www.nature.com/articles/d41586-023-01902-4(2023).Figure2.Estimatedcumulativehectaresburnedfromsatellite-detectedhotspotsfor2023comparedtorecentyears.Alsoshownisthe2003–2023average.Toillustratethescaleofthefires,theequivalentlandareaofseveralcountriesisshown.JunMayJulAugSeptOctCapeVerdeCyprusIsraelBelgiumSwitzerlandCostaRicaSriLankaCzechiaPortugal024689.22023201420132015202120172018201920222016202020yearaverageMonthCumulativehectaresburnedinCanada(millionsofhectares)EquivalentareaofcountryThetrendofintensefireactivitypersistedthroughoutJune,resultinginamonthlytotalburnedareaof5.28millionhectares.ThisfigurerepresentsanewJunerecordinthepast20yearsandsurpassesthecumulativeburnedareaattheendofJuneforallyearscombinedoverthelastdecade(2012–2022).Datasource:CanadianWildlandFireInformationSystem1.Lastupdated:July2,2023.ForewordOutlookRecentEventsContactsandInformation2626Furthermore,over520,000hectareswereburnedinasingleday,markingthehighestdailytotalintheavailabledata.Thecurrentwildfires'extentexceedsthe20-yearaverageforthistimeofyearbyafactoroften.WhatSparkedtheEarlyOnset?Theearlystarttotheseasoncanbeattributed,inpart,totherecord-breakingheatexperiencedacrosswesternCanadainMay4.Thiscomesagainstabackdropofrisingtemperaturesacrossallseasonsinthecountryoverthelastfewdecades5.Theparticularlyhotanddryweatherthisyearcreatedaconduciveenvironmentforfireignitionandrapidwildfirespread.Thisyearisnotanisolatedevent,butpartofalargertrendobservedinCanada,andacrosstheworld.WesternCanada,inparticular,hasexperiencedanoticeableincreaseinboththesizeofburnedareasandthefrequencyoflargefiressincethe1960s,oftensparkedbylightningstrikes2.Human-causedfires,whichareoftensmallerinscale,arealsohappeningmorefrequentlyduringthetransitionalseasons,whichhavebeenextendedduetoearlierspringsandlaterwinters.Theseshiftsinthefireseasoncoincidewithperiodswhenvegetationbecomeshighlyflammableduetoreducedwatercontent,thesheddingofleavesfromdeciduoustrees,andincreasedcuring.Thesefactors,togetherwiththeeffectsofclimatechange,areprojectedtoexacerbatefireactivitythroughoutCanadabytheendofthecentury2.4Summertemperaturesarriveearly.NASA.https://earthobservatory.nasa.gov/images/151349/summer-temperatures-arrive-early(2023).5EnvironmentandClimateChangeCanada.GovernmentofCanada.https://www.canada.ca/en/environment-climate-change/services/environmental-indicators/temperature-change.html(2023).Figure3.Estimatednumberofdailywildfirehotspotsfor2023(pinkline)andallotheryears2003–2022(greylines).leMayJunJulAugSeptOct010002000300040005000600070008000900010000202320032022MonthNumberofdailyhotspotsDatasource:CanadianWildlandFireInformationSystem1.Lastupdated:July2,2023ForewordOutlookRecentEventsContactsandInformation2727BeyondtheFlamesThe2023seasonhaspresentedchallengesforfirefightersandemergencyresponders.Thefireshavevariedinsize,number,andlocation,makingitexceptionallydifficulttocombatthem.Consequently,evacuationshavebeennecessary,andasofJuly2,over600structureshavebeendamagedordestroyed.EvenregionsnotdirectlythreatenedhavebeenimpactedassmokedriftsacrossNorthAmerica.ThisresultedindeterioratedairqualityconditionsduringearlyJune,particularlyinmajorcitieslikeBoston,NewYorkCity,Philadelphia,andWashington,D.C.Figure4.Theproportionofthetotalburnedareabyprovince/territory,asofJuly2,2023(bottom)comparedtothe20-year(2003–2022)average(top)forthesametimeperiod.le6020406080100020406080100Percentageofburnedarea%20yearaverage2023AlbertaBritishColumbiaManitobaNewBrunswickNewfoundlandandLabradorNovaScotiaNorthwestTerritoriesQuebecSaskatchewanYukonNunavutOntarioPrinceEdwardIslandBytheendofJune,thesmokefromthewildfireshadtraveledacrosstheAtlanticOcean,reachingasfarascentralandsouth-easternEngland,aswellaswesternScotland,asobservedbysatellites6.Fortunately,therehavebeennoreportedfatalities.ItisworthnotingthatwhilecomparingthecurrentwildfirestothedevastatingMcMurrayfiresin2016,whichholdtherecordfortheworstinsurednaturalcatastrophelossinCanadianhistory,wemustacknowledgethatwearestillinthemidstofthewildfireseason,andthefinaloutcomeremainsuncertain.Sofar,themajorityoftheburninghasoccurredinremoteareas,awayfromdenselypopulatedregions,allowingsometonaturallyextinguishtoacertainextent.Consequently,theimpactoncities,towns,andpropertieshasbeenrelativelylimited.Nevertheless,thewildfireshavealreadyaffectedmultiplesectorsoftheeconomy.Tourismhasdeclinedduetoconcernsaboutairqualityandsafetyissues.Thishasledtoadecreaseinvisitsandtheclosureofbusinessesinsomeregions7.Furthermore,theforestrysectorhasbeensignificantlyimpacted,withsawmillsforcedtoclose8.Thisdisruptioninthewoodproductsupplychainhastemporarilyboostedlumberpricesduetodwindlingsuppliesandrisingdemand.6Russell,R.SatelliteimagesshowCanadianwildfiresmokeoverUK.BBC.https://www.bbc.co.uk/news/uk-66058108(2023).7Blake,E.WildfiresImpactTourisminCanada.FinancialPost.https://financialpost.com/news/economy/wildfires-impact-tourism-canada(2023).8Nickel,R.Analysis:Canadianwildfiresshuttersawmills,driveuplumberprices.Reuters.https://www.reuters.com/business/environment/canadian-wildfires-shutter-sawmills-drive-up-lumber-prices-2023-06-12/(2023).Datasource:CanadianWildlandFireInformationSystem1.Lastupdated:July2,2023ForewordOutlookRecentEventsContactsandInformation2828Despitelimitedpropertydamagesofar,therepercussionsofthewildfiresareexpectedtoreverberateintheinsuranceindustry.Insurerswilllikelyreassesstheirpoliciesandpricingasconcernsmountovermorefrequentandsevereeventsinresponsetoclimatechange.Propertyownersinwildfire-proneareasmayfacehigherinsurancecostsduetothecombinedrisksassociatedwithclimatechangeandinflationarypressures.LookingAhead:TheLingeringThreatAswemoveforwardthroughthesummer,thelingeringthreatofwildfireswillcontinuetoloomlarge.AlthoughthepeakofElNiño(seeSection3.1)isunlikelytocoincidewiththecurrentfireyear,theapproachingsummermonthsbringthepotentialformoreextremeheatanddryweather,whichareprimersforfurtherfireactivity.WiththeCanadianwildfireseasonextendinguntiltheendofSeptember,apressingquestionarises:justhowfarwillthisyear'swildfiresspread?Onlytimewillrevealthetrueextentoftheenvironmentalandsocioeconomicimpacts.ForewordOutlookRecentEventsContactsandInformation29292.7AviewofcatastrophicfloodingfromacrosstheworldbyNeilGunnandCameronRyeFloodingaffectedmillionsofpeopleinthefirstsixmonthsoftheyear,withsignificanthumanitarianandeconomicconsequencesacrosstheworld.Therewerenearly100majorfloodeventsrecordedacrossallpopulatedcontinentsinthefirstsixmonthsoftheyear1.Thefloodsthathadthelargestsocio-economicimpactsarehighlightedinFigure1,manyofwhichweretheresultofheavyrainfalloverwhelmingriversandurbandrainagesystems,orthecombinationofinlandandcoastalfloodingfromtropicalcyclones.Floodingisoneofthemostprevalentnaturalhazards,affectinglivelihoodsanddevelopmentopportunitiesglobally2,3.RecentresearchfromtheWorldBankhasfoundthat1.8billionpeople(23%oftheworld’spopulation)liveinareasthataredirectlyexposedto1-in-100yearflooding4.1BasedondatacompiledfromFloodList.com2Parvin,G.A.,Shimi,A.C.,Shaw,R.&Biswas,C.FloodinaChangingClimate:TheImpactonLivelihoodandHowtheRuralPoorCopeinBangladesh.Climate4,60(2016).3Balgah,R.A.,Ngwa,K.A.,Buchenrieder,G.R.&Kimengsi,J.N.ImpactsofFloodsonAgriculture-DependentLivelihoodsinSub-SaharanAfrica:AnAssessmentfromMultipleGeo-EcologicalZones.Land12,334(2023).4Rentschler,J.,Salhab,M.&Jafino,B.A.Floodexposureandpovertyin188countries.NatureCommunications13,3527(2022).Thispatterncontrastswitheconomicexposures,whichareconcentratedinhigherincomecountries,with$9.8trillionofeconomicactivity(12%ofthegrossglobalproductin2020)locatedinbeflood-proneareas.Thisyearhasbeennoexception,withmultipleeventsresultinginsignificanthumanitarianimpactsforlowandmiddleincomepopulations.Mostofthesepeople(89%)areinlowandmiddleincomenations.ForewordOutlookRecentEventsContactsandInformation3030HeavyrainsstrucktheHornofAfricainMarch,affecting460,000peopleinEthiopiaandSomalia.ThiswasfollowedbytheAfricanGreatLakesFloodsinAprilandMay,whichkilledover600peopleandcausedextensivedamageintheDemocraticRepublicoftheCongo,Rwanda,andUganda.InAsia,monsoonfloodingandlandslidesoccurredinMalaysiainMarch,whileExtremelySevereCyclonicStormMochacausedwidespreadcoastalfloodinginMyanmarandBangladesh,displacinghundredsofthousandsofpeopleinMay(Section2.3).AndinSouthAmerica,Brazilsawmultiplemajorfloodeventsacross12ofthecounty’s26states.Themostnotablewastherecord-breakingfloodinginthestateofSãoPauloinFebruaryafter680mmofrainfellwithina24-hourperiod.Fromaneconomicperspective,thelargesteventswereinNewZealand(Section2.4),Italy(Section2.8),andCalifornia.TheSouthernHemispheresummerof2022/2023wasthewettestonrecordforNewZealand’sNorthIsland,whichculminatedinFebruarywithCycloneGabrielleproducinganestimated$8.4billionineconomicdamages.IntenserainfallinNorthernItalyinMayledtofloodingthatproduceddamagesofroughly$5.4billion,whileatthebeginningoftheyear,severefloodinginCaliforniabroughtonbyaseriesofatmosphericriversisestimatedtohavecausedeconomiclossesofupto$7billion.Climatechangeisexpectedtoincreasefloodriskbyincreasingtheintensityofrainfallandraisingsealevels5.Furthermore,aspopulationscontinuetogrow,morepeoplearelivinginfloodproneareas,increasingtheexposureofvulnerablecommunities.Inaddition,accessibleandcomprehensiveinsurancesolutionsarevitaltoclosetheprotectiongapandensurethatcommunitieshavethenecessaryfinancialsupporttorecoverandrebuildafternaturalcatastrophes.Giventhatfloodsaffectmorepeoplethanmostothernaturaldisasters,itisimperativeforgovernments,corporations,andotherorganizationstoproactivelyinvestinresiliencemeasures.Thesestepsincludeimplementingsustainableinfrastructure,improvingearlywarningsystems,anddevelopingrobustdisasterresponsestrategies.5Pörtner,H.O.et.al.IPCCSpecialReportontheOceanandCryosphereinaChangingClimate(IntergovernmentalPanelonClimateChange,2019).ForewordOutlookRecentEventsContactsandInformation3131Figure1.Floodeventswiththelargestsocio-economicimpactsthatoccurredbetweenJanuaryandJune2023.California,Dec–JanAtmosphericrivers22fatalities,6,000displacedEconomicloss:Upto$7BnCuba,Jun8–9Heavyrainfall360mmin24-hours>7,000displacedFlorida,Apr12–13FortLauderdaleHeavyrainfall650mmin12-hoursHaiti,Jun2–3Heavyrainfall42fatalities6,500displacedBrazilFeb18–19SãoPaulo,heavyrainfall680mmin24-hours44fatalitiesItaly,May15–17Emilia-Romagna,heavyrainfall15fatalitiesEconomicloss:$5.4BnHornofAfrica,MarHeavyrainfall90fatalities460,000displacedAfricanGreatLakes,Apr–MayHeavyseasonalrains616fatalities2,500missingTCFreddy,Feb–Mar1,434fatalities1,700,000displacedEconomicloss:$1.5BnTCCheneso,Jan19–2333fatalities34,000displacedTCMocha,May14438fatalities>500,000displacedPhilippines,Jan–FebHeavyrainfall40fatalities>200,000displacedTCGabrielle,Feb12–1611fatalitiesEconomicloss:$8.4BnMalaysia,MarHeavyrainfall630mmin48-hours61fatalities46,000displacedTC=TropicalCycloneForewordOutlookRecentEventsContactsandInformation32322.8Emilia-Romagnafloods:aproductofurbanizationandclimatechangebyFrancescoSerinaldiandChrisKilsbyAfterintenserainfallproducedmajorfloodingandlandslidesinadenselypopulatedregionofthePoValley,welookathowclimateandland-usechangeareaffectingfloodriskinNorthernItaly.FloodingdevastatedItaly'sPoValleyinMay,affectingImola,Cesena,Forli,Faenza,Ravenna,Lugo,andsurroundingareas(Figure1).Theregionwashitbytwoevents,thefirstbetweenMay2and3,andthesecondbetweenMay15and17.Thesecondwasthemostsevere,withanaverageof200mmofrainfallingacrosstheregionina36-hourperiod,andsomeareasrecordingover500mm.Therewere15fatalities,over36,000peopleevacuated,atleast376landslides,and714closedroads(445totally,and259partially)1.Theregionalgovernmenthasprovidedaprovisionalestimateof€5billion(U.S.$5.4billion)2ineconomicdamage,butthisfigureisexpectedtochangeasthefullextentofthedisastermaterializes.1ERCC-EmergencyResponseCoordinationCentre-Maps.https://erccportal.jrc.ec.europa.eu/ECHO-Products/Maps#/maps/4501(2023).2Servono5miliardi:lacontadeidannitracampi,aziende,stradeeturismo.https://www.repubblica.it/economia/2023/05/21/news/danni_alluvione_emilia_romagna_stanziamento_fondi-401052309/?ref=RHLF-BG-I400748377-P1-S1-T1(2023).3Persiano,S.etal.Changesinseasonalityandmagnitudeofsub-dailyrainfallextremesinEmilia-Romagna(Italy)andpotentialinfluenceonregionalrainfallfrequencyestimation.JournalofHydrology:RegionalStudies32,100751(2020).Figure1.FloodinginEmilia-RomagnafromMay15toMay17.Source:JBARiskManagementForewordOutlookRecentEventsContactsandInformation3333Inthepastfewyears,Emilia-Romagnahasbeenaffectedbyseveraldestructivefloodevents,includingsignificantriverflooding(e.g.SecchiaandPanaroRiversinJanuary2014,EnzaRiverinDecember2017,RenoRiverinFebruary2019,IdiceRiverinNovember2019),flash-floodinginmountainousareas(e.g.AltaValNureinSeptember2015),andintenserainfall-inducedfloodinginurbanareas(e.g.RiminiinJune2013)3.AccordingtotheItalianInstituteofEnvironmentalProtectionandResearch,around63%ofbusinessesandhomesinEmilia-Romagnaarelocatedwithinthe1-in-100yearfloodzone.Moreover,theregionplaysacrucialroleintheItalianeconomy,contributingmorethan40%ofItaly’sGrossNationalProduct3.AlthoughItalyisaflood-pronecountryandregionslikeEmilia-Romagnahavehighexposedvalue,theinsurancepenetrationislowerthanthatofotherdevelopedEuropeancountries.Non-lifeinsurancepenetrationinItalywas1.9%ofGDPin2021.Incomparison,theratewas2.3%inGermany,2.9%inSpain,4.0%inFrance,and7.4%inTheNetherlands.Ifmotorliabilityinsurance(compulsoryeverywhere)isexcluded,thegapinnon-lifepremiumsbetweenItalyandotherEuropeancountriesisevenwider4.AcademicresearchindicatesthatfloodriskinthePoValleyischangingduetotwomainfactors.First,climatechangeisresultingintheintensificationofextremehydrologicalevents,whichmeteorologistshaveattributedtoachangeintheatmosphericdynamicsintheMediterraneanarea.Previouslythemajorityofweathersystemsmovedfromeast-to-west,butwearenowseeinganincreaseinnorth-to-southsystems.ThisresultsinmoreextremeprecipitationeventsbecausethereisalargertemperatureandhumiditygradientbetweenNorthAfricaandNorthernEurope5.Second,therehasbeenanincreaseinthenumberofpeopleexposedtofloodingduetoland-useandland-covermodifications3.ThegovernmentofEmilia-Romagnahasenabledasignificantexpansionofurbanareasoverthelastfourdecades.Duringfloodevents,theman-madedrainagenetworkisincreasinglyoverloadedduetothesignificantproportionoflandthathasbeenconvertedfromagriculturaltourban.Atthesametime,floodinghascausedmoresignificantdamagesduetotheincreaseinexposurevalues6,7.4AssociazioneNazionalefraleImpreseAssicuratrici.ItalianInsurance2021-2022.https://www.ania.it/documents/35135/126704/ITALIAN+INSURANCE-2022+EN_WEBVER.pdf/03211e47-ad5c-2268-d994-541120c6e55a?version=1.0&t=1668508791602(2022).5Rousi,E.,Selten,F.,Rahmstorg,S.,&Coumou,D.ChangesinNorthAtlanticAtmosphericCirculationinaWarmerClimateFavorWinterFloodingandSummerDroughtoverEurope.JournalofClimate34Issue6,(2021).6Pistocchi,A.,Calzolari,C.,Malucelli,F.&Ungaro,F.SoilsealingandfloodrisksintheplainsofEmilia-Romagna,Italy.JournalofHydrology:RegionalStudies4,398–409(2015).7Sekovski,I.etal.CouplingscenariosofurbangrowthandfloodhazardsalongtheEmilia-Romagnacoast(Italy).NaturalHazardsandEarthSystemSciences15,2331–2346(2015).Withmostofthepopulationexpectinggovernmentsupportfollowingnaturaldisasters,ratherthanbuyinginsurance,thereisaneedforthecountrytoreviewhowtoimproveresilienceandreducetheburdenongovernmentfinances.Thisisespeciallytrueoverthecomingdecadeswhenclimatechangeisexpectedtoincreasethefrequencyandseverityoffloodevents.SuccessivefloodeventsintheEmilia-RomagnaregioninrecentyearshavehighlightedthevulnerabilityofthePoValley.ForewordOutlookRecentEventsContactsandInformation34342.9WhyhavetherebeensofewEuropeanwinterwindstormsin2022/2023?byAdamScaife,DavidB.Stephenson,MatthewPriestley,NickyStringer,andDanielBannisterThe2022/2023Europeanwindstormseasonwasunusuallyquiet,deviatingfrompredictionsofheightenedstormactivity.FactorssuchasLaNiña,theMaddenJulianOscillation,andasuddenstratosphericwarmingeventlikelycontributedtothereducedstorminess,highlightingthechallengesofseasonalforecasting.Duringthewinterof2022/2023,Europeanextratropicalcyclones,knownfortheirdestructivenatureandsignificantimpact,werenotablyscarce.Thisabsenceofnamedstormsalignedwithearlywinterforecastsbutcontradictedpredictionsthatanticipatedheightenedstormactivitylaterintheseason.ThisraisesthequestionofwhythereweresofewstormsinEuropeduringthiswinter.UnderstandingthefactorscontributingtoEuropeanextratropicalcyclonefrequencyiscrucial,especiallyforindustrieslikeinsuranceandagriculturethatdependonweatherinformation.Historically,theUKMetOfficehasrecordedanaverageof4.5namedEuropeanextratropicaleventsperyearsincethenamingconventionwasintroducedin2016.However,the2022/2023seasonstoodoutwithonlyonestorm(Otto)namedbytheDanishMeteorologicalInstituteinFebruary2023.Thisstandsinstarkcontrasttothepreviousyear,whichexperiencedarapidsuccessionofnamedevents,includingthreewithinsevendays(Dudley,Eunice,andFranklin)forthefirsttimesincethenamingconventionbegan.Despitethelimitedoccurrenceofnamedstorms,thetotalnumberofextratropicalcyclonesduringwinter2022/23remainedclosetotheaverage(Figure1).Figure1.NumberofNorthAtlanticstormsperNorthernHemispherewinter(Dec–Feb).Despitethelackofnamed(intense)storms,thetotalnumberofstormswasclosetoaverageinwinter2022/2023.Datasource:CopernicusClimateChangeService(C3S).CompleteERA5globalatmosphericreanalysis.DOI:10.24381/cds.143582cf(2023).1960197019801990Year200020102020Stormsperwinter10152025303540ForewordOutlookRecentEventsContactsandInformation3535Thequestionarises:Whathappenedtotheintensewindstormsthiswinter?Ourinitialnullhypothesisisalwaysthatinternal,unpredictableclimatevariability,withnoparticularidentifiablecause,leadstovariationbetweenoneperiodandthenext.Someaspectsofthequiescentwinterof2022/23willnodoubtbeattributabletothisunpredictable‘chaos’.Individualseasonalforecastsshowedsubstantialuncertaintyandsomeofthemdidspantheobservedoutcome,butcanwedigdeeper?ObservationsandclimatemodellingstudiesindicatethatLaNiñaoftenleadstoatmosphericblocking(reducedstorminess)intheearlywinterandenhancedwesterlies(increasedstorminess)inthelatewinter1,2.TherecentLaNiñamaythereforepartiallyexplaintheabsenceofintensestormsinearlywinterbutfailstoaccountforthelatewinterperiod.TheMaddenJulianOscillation(MJO),anaturalweatherpatternsignificantlyimpactingtropicalregionsandglobalweather,alsoplayedacrucialroleduringthiswinter.TheMJOprogressesthroughdistinctphases,eachrepresentingdifferentweatherpatterns.ExtensiveresearchsupportsthenotionthattheMJOhasnotableeffectsontheNorthAtlanticregion3,4.Phases6and7oftheMJOareparticularlyassociatedwithheightenedrainfallandstormactivityinthewesternPacificOcean,whichcaninfluenceweatherpatternsintheNorthAtlanticarea,causingblockedconditions(andthereforereducedstormactivityoverEurope)foruptotwoweeks.LateNovember2022witnessedanexceptionallyintenseperiodcharacterizedbyphases6and7oftheMJO.ThisheightenedMJOactivitywasthenfollowedbyarelativelycalmandcoldperiodobservedinearlytomid-December2022.Throughoutthewinter,theMJOremainedactive,withrecurringsignificantshiftstophases6and7,followedbysubsequenttransitionstocoolerperiods.Thesepatternsculminatedinasuddenstratosphericwarming(SSW)event5.1Moron,V.&Gouirand,I.SeasonalmodulationoftheElNiño-SouthernOscillationrelationshipwithsealevelpressureanomaliesovertheNorthAtlanticinOctober-March1873-1996.InternationalJournalofClimatology23,143–155(2003).2Hardiman,S.C.etal.TheimpactofstrongElNiñoandLaNiñaeventsontheNorthAtlantic.GeophysicalResearchLetters46,2874–2883(2019).3Cassou,C.IntraseasonalinteractionbetweentheMadden–JulianOscillationandtheNorthAtlanticOscillation.Nature455,523–527(2008).4Lin,H.,Brunet,G.&Fontecilla,J.S.ImpactoftheMadden–JulianOscillationontheintraseasonalforecastskilloftheNorthAtlanticOscillation.GeophysicalResearchLetters37(2010).5Schwartz,C.&Garfinkel,C.I.RelativerolesoftheMJOandstratosphericvariabilityinNorthAtlanticandEuropeanWinterClimate.JournalofGeophysicalResearch:Atmospheres122,4184–4201(2017).Theglobalclimatestateforwinter2022/23wasinfluencedbythethirdLaNiñaeventinarowsince2020.ForewordOutlookRecentEventsContactsandInformation3636Suddenstratosphericwarmingeventsareoften(in~70%ofcases)followedbycolderperiodswitheasterlywindsovernorthernEuropecomparedtonormal6,7,8.Thesecirculationpatternscorrespondtoaweakerjetstreamwithlessfrequentwindstorms.Figure2.Strengthofthestratosphericpolarvortexasmeasuredbydailywindspeedsinthestratosphereat60Nand10hPaforthelatewinterperiodfromFebruary2023.Forecastsfrom2023areshowninredandmeanclimatologyisshowninblue.Notetheemergenceofastrongsignalforacollapseofthepolarvortex(andhenceasuddenstratosphericwarming)inforecastsmadeinearlyFebruary.Source:MetOffice6Bett,P.E.etal.UsinglargeensemblestoquantifytheimpactofsuddenstratosphericwarmingsandtheirprecursorsontheNorthAtlanticOscillation.WeatherandClimateDynamics4,213–228(2023).7Kidston,J.etal.Stratosphericinfluenceontroposphericjetstreams,stormtracksandSurfaceWeather.NatureGeoscience8,433–440(2015).8Scaife,A.A.etal.SeasonalWinterforecastsandthestratosphere.AtmosphericScienceLetters17,51–56(2016).9Fereday,D.R.,Maidens,A.,Arribas,A.,Scaife,A.A.&Knight,J.R.SeasonalforecastsofNorthernHemisphereWinter2009/10.EnvironmentalResearchLetters7,034031(2012).10Marshall,A.G.&Scaife,A.A.Improvedpredictabilityofstratosphericsuddenwarmingeventsinanatmosphericgeneralcirculationmodelwithenhancedstratosphericresolution.JournalofGeophysicalResearch115,(2010).StratosphericPolarVortexstrength:2FebStratosphericPolarVortexstrength:5FebWhilesuddenstratosphericwarmingeventsareofteninvolvedincoldwinters9,theyrepresentachallengeforseasonalforecastsduetotheirrelativelyshortleadtimeforprediction10.Figure2illustratestheemergenceofforecastsignalsforthesuddenwarmingof2023,whichwerenotapparentuntilearlyFebruary.ThislatewintersuddenstratosphericwarmingeventlikelycontributedtoreducedstorminessinlaterwinterwhenwewouldhaveotherwiseexpectedincreasedstorminessfromLaNiña.ForewordOutlookRecentEventsContactsandInformation3737Someofthesesignals,suchastheLaNiñaevent,werepredictedinadvanceofthewinter,andofficialMetOfficelong-rangeoutlookscapturedtheweakwindsandlackofstormsobservedovertheUKthroughoutthewinter(Figure3).Theforecastsalsohighlightedthattheriskofstormyweatherwashighestinlatewinter,aligningwiththelatewinterLaNiñateleconnection,whichtendstostrengthenthestormtrackintheAtlantic.However,theeffectofLaNiñawasreducedthisyearduetoasuddenstratosphericwarminginFebruary.Figure3.MetOfficelongrangeoutlookforwinter2022/2023issuedinNovember2022.Source:MetOfficeInsummary,itislikelythatacombinationofLaNiña,intenseMJOactivity,andasuddenstratosphericwarmingeventweakenedthestormtrackinwinter2022/23.15%chancetheseasonwillbeCOLD25%chancetheseasonwillbeDRY30%chancetheseasonwillbeCALM65%chancetheseasonwillbeNEARAVERAGE65%chancetheseasonwillbeNEARAVERAGE65%chancetheseasonwillbeNEARAVERAGE20%chancetheseasonwillbeMILD10%chancetheseasonwillbeWET5%chancetheseasonwillbeWINDY0.8xthenormalchance1.3xthenormalchance1.5xthenormalchance1.1xthenormalchance1.1xthenormalchance1.1xthenormalchance1.0xthenormalchance0.5xthenormalchance0.3xthenormalchanceTemperaturePrecipitationWindspeedForewordOutlookRecentEventsContactsandInformation3838OutlookForewordOutlookRecentEventsContactsandInformation39393.1FromthetropicalPacific,ElNiñoisinthewindbyScottSt.GeorgeForthreeyearsinarow,Earth’slargestoceanhasbeenstuckinitsLaNiñaconfiguration.NowthatthePacifichasflippedtoElNiño,businessesshouldprepareforrecord-hightemperatures,weirdweather,andslowereconomicgrowth.ThetropicalPacificOceanhasbeenremarkablydependablethesepastfewyears.Sincethestartof2020,thetradewindshaveblownwestacrosstheequatorintheirusualfashion,pushingwarmwaterawayfromSouthAmericaandtowardIndonesiaandPapuaNewGuinea.Thisarrangementofairandoceancurrentshasbeenunusuallyvigorousoverthisperiod,withenergizedwindsandevenhotterwaterinthewest.ThissituationisnamedLaNiñaandtheuncommonpersistenceofthislatest‘tripledip’eventhassetthetableforglobalclimatethreeyearsrunning.ButLaNiñahasnowexitedthestage,andthespotlightisabouttobetakenbyitsmirroropposite.ForewordOutlookRecentEventsContactsandInformation4040ThePacific’sotherwayofbeingiscalledElNiño.Underitsoversight,thetradewindsslackenandthemassivepoolofwarmwaterinthewestsloucheseastward,takingupapositioninthecentralPacific.NormallytheatmosphereabovethePacificformsasingleloop,whereairrisesinthewest,trackseastwardathigheraltitudes,sinksbackdownoffthecoastofSouthAmerica,andthenrejoinsthetradewinds.DuringanElNiño,thatsinglecellissplitintwo.ThegrandcolumnofconvectionrisesfromthemiddleofthePacificratherthanitswesternarm,andairispushedbotheastandwestfromthatcentrallocation(Figure1).AsputbyJoshWillis,aclimatescientistandoceanographeratNASA’sJetPropulsionLaboratory,“WhenthePacificspeaks,thewholeworldlistens”1.TheserearrangementsandreversalstossthetropicalPacific’sweatherupsidedown.ElNiñobringsdroughtandwildfiretoIndonesia,conductssurpriserainstormsandfloodsintothenormallydryareasofEcuadorandPeru,andcausesthemarinefoodwebsurroundingtheGalapagosIslandstocollapse.ButbecausethetropicalPacificOceanissoenormousandholdssomuchheat,ElNiñohasareachfarbeyondtheconfinesofthebasinitself.Figure1.GeneralizedWalkerCirculation(December-February)duringENSO-neutralconditionsandGeneralizedWalkerCirculation(December–February)anomalyduringElNiñoevents,overlaidonmapofaverageseasurfacetemperatureanomalies.Source:Climate.gov1NASAEarthObservatory.LaNiñatimesthree.https://earthobservatory.nasa.gov/images/150691/la-nina-times-three(2022).ForewordOutlookRecentEventsContactsandInformation41412NationalOceanographicandAtmosphericAdministration.2020wasEarth’s2nd-hottestyear,justbehind2016.https://www.noaa.gov/news/2020-was-earth-s-2nd-hottest-year-just-behind-2016(2021).3Lenssenetal.SeasonalforecastskillofENSOteleconnectionmaps,WeatherandForecasting35:2387-2406.https://doi.org/10.1175/WAF-D-19-0235.1(2020).4Karnauskasetal.Couplingbetweenairtravelandclimate,NatureClimateChange5:1068-1073.https://www.nature.com/articles/nclimate2715(2015).5St.GeorgeandWolfe.ElNiñostillswinterwindsacrossthesouthernCanadianPrairies,GeophysicalResearchLetters36.https://doi.org/10.1029/2009GL041282(2009).6CallahanandMankin.PersistenteffectofElNiñoonglobaleconomicgrowth,Science.https://doi.org/10.1126/science.adf2983(2023).ExtratropicalreverberationsElNiñoandLaNiñaarethesingleleadingcauseofyear-to-yearchangesinweatherandclimateacrosstheplanet.HowisitthatrippleeffectsfromthePacificOceanechosofarafield?OnethreadfollowstheRossbywaves,enormousplanet-spanningtwistsandturnsinEarth’satmospherethatguideheatandmoistureawayfromtheEquatorandtowardsthepoles.DuringElNiño,Rossbywavesadoptamoremeanderingpathandalterthetrajectoryofthejetstreams(andthereforestormsystems)overthecontinents.What’smore,theatmosphereabsorbsmoreheatwhiletheoceantakesupless,andsotwotothreemonthsaftertheeventbegins,globalsurfacetemperaturestakeanadditionalstepupwards.That’sthereasonwhymajorElNiñoyearsareamongthehottesteverrecorded,includingthecurrentrecordholder,20162.AllElNiñosarealikeintheirgeneralstructurebuteachonealsohasitsownpeculiarities.Someevents,forinstance,featureunusuallywarmwateronlyinthecentralequatorialPacificanddonotinvolvemuchchangeintheeasternpartoftheocean,whereElNiñoeventsgenerallyareborn.Inthesamefashion,whiletheirimpactsonthegroundarenotidenticalfromeventtoevent,overallthereareconsistentpatternsthattendtorepeat.AbogstandardElNiñobringsdroughttoIndonesia,Australia,CentralAmericaandnorthernSouthAmerica,andheavyrainstothesouthernUnitedStates,southernSouthAmerica,andtheHornofAfrica3.Theycanalsoconjureupmoreunusualreactionsthroughtheirinterferencewiththejetstream.ForairtravelbetweenHawaiiandthecontinentalUnitedStates,ElNiñocanlengthenorshortenflightdurationsbymorethan30minutes,dependingonwhethertheflightiseastwardorwestward4.Fartherdownstream,ElNiñocausesground-levelwindstoweakenacrosslargeswathesofCanadaandthenorthernUnitedStates,sometimesformonthsatatime5.Astheleadingcauseof‘winddrought’inNorthAmerica,animpendingElNiñoisanillomenforrenewableenergyproduction.Intotal,theknock-oneffectsofElNiñoextractamassivetollontheglobaleconomy.ArecentstudyfromDartmouthUniversityputtheglobalpricetagofthemajor1983and1998eventsatnearly$4.1trillionand$5.7trillion,respectively6.ThatanalysisarguedthemacroeconomiceffectsofElNiñoarebothabruptandchronic.Extremeweatherduringtheeventitselfcauseslossoflife,propertydamage,andwildfluctuationsincropprices.ButElNiñoalsoreduceseconomicgrowthinthelongterm,particularlyintropicalcountrieswhereitsimprintisstrong(includingEcuador,Brazil,andIndonesia),andthatstagnationcanpersistforfiveyearsormoreaftertheinitialevent.ForewordOutlookRecentEventsContactsandInformation4242Awhisperorathunderclap?ByreadingthesignsinthetropicalPacific,climatescientistsareabletospotElNiñoandLaNiñaonthehorizonthreetosixmonthsinadvance.Currentlytheselong-termforecastsaremadeinoneofthreeways.ThefirstandoldestapproachbuildsstatisticalmodelsthatpredictanindexoftheElNiño/LaNiñasystembasedonothermeasuredaspectsofthetropicalPacific(suchasdeepoceantemperatures,airpressurepatterns,oreventhestateoftheindexinpreviousmonths).Thesecondapproach—dynamicalmodeling—useshigh-performancecomputerstosimulatethephysicalbehavioroftheoceanandatmosphereoverthecomingmonths.Thethird(andnewest)techniquesearchesthehugedatabaseofclimatemodeloutputtofindallcaseswherethesimulationcloselyresemblesthecurrentstateofthePacificOcean7.ResearcherscanthentracehowthoselookalikesevolvedoverthenextseveralmonthswithinthesimulationandusethatbehaviortoforecastElNiñointherealworld.7CooperativeInstituteforResearchinEnvironmentalSciences.Miningclimatemodelsforseasonalforecasts.https://cires.colorado.edu/news/mining-climate-models-seasonal-forecasts(2019).8InternationalResearchInstituteforClimateandSociety.ENSOforecast.https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/?enso_tab=enso-sst_table(2023).9NationalOceanographicandAtmosphericAdministration.Model-Analogs(MA)andLinearInverseModel(LIM)forecastsforMonths1-24.https://psl.noaa.gov/forecasts/seasonal/(2023).10ClimateGenn.DrJenniferFrancis–2023’ssymptomsofclimatechaos,ElNiño,oceanheatwaves,andarcticseaicelows.https://www.patreon.com/posts/dr-jennifer-of-83526180(2023).Thestatisticalmodelsaremuchmorecautious,suggestingthetropicalPacificwilljustbarelyexceedthethresholdtoqualifyasanElNiño.Andtheanalogforecastssitinthemiddle—anElNiño,butnotaparticularlystrongone9.Seasonalforecasting,evenwhentiedtoaphenomenonasintensivelystudiedasElNiño,isstillenormouslychallenging.ThatchallengeismademoredifficultbecauseElNiñoisitselfpartofourchangingglobalclimate.AsnotedbytheWoodwellClimateResearchCenter’sDr.JenniferFrancis10,we’veneverhadastrongElNiñoundersuchhighglobaltemperaturesand,perhapsmorecrucially,recordheatcontentintheoceans.Becauseourforecastingtechniquesareoperatinginunchartedwaters,weshouldperhapsbecautiousaboutourabilitytopredictElNiñoandanticipateitsimpacts.ButifthePacificdoesmanifestanElNiñobytheendoftheyear,weshouldappreciateitspotentialtoredrawtheglobalclimatemapand,toborrowthewordsofDr.Francis,to“expectchaos”initswake.Asofmid-June20238,nearlyallmodelspredictthatElNiñowillbeinforcepasttheendoftheyearbuttheydisagreequitealotaboutitsstrength.Thedynamicalmodelsarecallingforaverystrongevent,perhapsoneofthebiggestofthepastthreedecades.ForewordOutlookRecentEventsContactsandInformation43433.2The2023NorthAtlantichurricaneseason:RecordhotAtlanticOceanversusElNiñobyJamesDoneTheglobaltropicshaveflippedfromLaNiñatoElNiño.ElNiñoisoneofourmostdependablesourcesofseasonalhurricaneforecastskill,butthisyear’srecordhotNorthAtlanticOceanwillputElNiño’shurricane-suppressinginfluencetothetest.ThoseimpactedbythehyperactiveNorthAtlantichurricaneseasonsof2020and2021willseethisyear’sElNiñoasawelcomedevelopment.ElNiñohashistoricallysuppressedhurricaneseasonsbydrivingstrongwindsaloftovertheNorthAtlanticthatcantearnascenthurricanesapart.TheprolongedstringofthreesuccessiveseasonsofLaNiñaconditionsjustended.SinceearlythisyearthewarmwatersthatwerepiledupovertheWesternEquatorialPacificOceanhaveslippedbackEast.OceansurfacetemperaturesroseataremarkablepaceintheCentralandEasternEquatorialPacificOcean(Figure1),andthisisbackedbywarmththroughouttheunderlyingupperlayersoftheocean.ThesetemperaturespassedakeythresholdtriggeringtheU.S.NationalOceanicandAtmosphericAdministrationtodeclareanElNiñoonJune8.Figure1.Departureofseasurfacetemperaturefromalong-termaverage(°C)validonJune15,2023.Source:U.S.NationalOceanicandAtmosphericAdministrationCoralReefWatch.1BenNoll[@BenNollWeather].It’sofficial:theAtlanticMainDevelopmentRegion(MDR)hasreachedarecordhightemperatureforthemonthofJune.Twitter.https://t.co/FpdCYVGXuW(2023).Meanwhile,overintheNorthAtlanticsurfacewatershavebeenwarmingrapidly.Thesubtropicalhigh-pressuresystemhasbeenunusuallyweakthisyear,limitingthecoolingeasterlywindsacrossthetropicalNorthAtlantic.Inresponse,thetypicalseasonalwarmingoftheNorthAtlantichasoccurredatarapidpaceandpartsofthetropicalAtlanticarenowbreakingJunetemperaturerecords1(Figure1).ForewordOutlookRecentEventsContactsandInformation4444Ratherominously,watersarehotterthantheywereinJune2005beforethedevastating2005hurricaneseason.TheAtlanticispoisedtobreakmoremonthlytemperaturerecordsduringtheupcominghurricaneseason.Giventhathurricanesgettheirenergyfromtheocean,thisunprecedentedwarmthwillfuelanyhurricanethatcanavoidElNiño’sstrongwindsaloft.Thisyear’scombinationofexpectedmoderate-to-strongElNiñoandAtlanticOceanwarmthfallsattheedgeofhistoricalexperience(Figure2).Thesetwoopposingfactorsforthe2023hurricaneseasonhaveledtodifferingopinionsamongthemajorforecastingcenters.ThosethatthinkthehostilewindsbroughtbyElNiñowillwinoutarecallingforbelownormalactivity,whilethosethatthinktheAtlanticOceanwarmthwillovercomeElNiño’swindsarecallingforabovenormalactivity.Forecastsfromuniversities,governmentagencies,privatecompanies,andotherorganizations3rangefrom11to28namedstorms.Theforecastsforhurricanesrangefrom5to15andmajorhurricanesfrom2to7.Thesepredictionsextendaboveandbelowthe1991-2020averageof14.4namedstorms,7.2hurricanes,and3.2majorhurricanes.Thiswiderangereflectstheuncertaintyintheopposingforcesforthisyear’shurricaneseason.Andifthatspreadwasn’tchallengingenough,enterclimatechange.2IRI–InternationalResearchInstituteforClimateandSocietyJune2023QuickLook.https://iri.columbia.edu/our-expertise/climate/forecasts/enso/current/(2023).3BarcelonaSupercomputingCenter.SeasonalHurricanePredictionshttps://seasonalhurricanepredictions.bsc.es(2023).4Dr.RobertRohde[@RARohde].Thisisgettingridiculous.OISSTprovidesareal-timedailyindexofoceansurfacetemperature(60S-60N).Forthelastmonthithasbeencontinuouslyreadinghigherthaninanypreviousyearandstillshowsnosignofsettling.Twitter.https://t.co/FeER7BViL2(2023).AkeyquestionthatscientistsarecurrentlytryingtoansweriswhetherElNiñoeventsintoday’sclimatewillsuppresshurricaneseasonsaseffectivelyastheyoncedid.ThosestrongwindstypicalofElNiñodependonoceantemperaturedifferencesaroundtheglobaltropics.Giventhatalloceansarewarming,anElNiñotodaymaynothavethesameinfluenceasanElNiñointhepast.GlobaloceansurfacetemperaturereachedrecordlevelsinApril4,makingthisyearatestoftheinfluenceofElNiñoinawarmingworld.Shouldweexpectourforecastingsystemstopickuponthispotentialforachanginginfluence?Therearetwomainmethodscurrentlyusedbydifferentagenciestoforecasthurricaneactivity:statisticalanddynamical.Seasonalhurricaneforecastsbasedonstatisticalmethods,whicharebuiltusinghistoricaldata,generallyreproducethesuppressingeffectofElNiñoandpointtoabelownormalseason.Ouralternativetostatisticalmethodsisusingthephysicallawsofweatherandclimateembodiedbydynamicalmethods.Thesemethodsarenotconstrainedtorepeathistoricalrelationshipsandmaycapturenew,unobservedeffectsinachangingclimate.Someofthesemethodsaresuggestingthattheinfluenceofthisyear’sElNiñomaynotbeasstrongashistoricalElNiñoeventswithlessstronghostilewindsovertheAtlantic.Consequently,thesepointtoanabovenormalseason.ManylessonswillbelearnedfromthedualandinteractinginfluencesofElNiñoandclimatechangeonthe2023hurricaneseason.Thiswillallowustoimproveourforecastingsystemstokeeppacewithourchangingclimate.Figure2.ScatterplotofMayNorthAtlanticseasurfacetemperatures(SSTs)intheMainDevelopmentRegion(MDR)versustheAugust-OctoberNino3.4regionSSTanomaly.Theellipsecontains90%ofhistoricaldatapoints,showingthatthisyearfallsattheedgeofhistoricalexperience.TheMDR(10-20°N,20-85°W)SSTwascalculatedusingtheNationalCentersforEnvironmentalPrediction(NCEP)reanalysis.TheNino3.4SSTanomalyisrelativetothe1991-2020average,fromtheNationalOceanicPredictionCentre(NOAA)/ClimatePredictionCentre(CPC).For2023,theNino3.4anomalyisthedynamicalmodelaverageforecastissuedonJune16,20232.Datasource:NationalOceanicPredictionCentre(NOAA)/ClimatePredictionCentre(CPC)ForewordOutlookRecentEventsContactsandInformation4545RelatedResearchInthissectionyouwillfindaselectionoffurtherarticleswhichhavebeenproducedwithourresearchpartnershipsfacilitatedbytheWTWResearchNetwork(WRN).Clicktoreadmore.ForewordOutlookWildfireresilienceinsurance:quantifyingtheriskreductionofecologicalforestrywithinsuranceByTheNatureConservancyandWTWJuly5,2021Anintegratedend-to-endapproachtotime-dependentearthquakeriskassessmentBySalvatoreIacolettiandJamesDalzielMay11,2023AdjustingaglobalfloodmodelByNeilGunnJune17,2022NaturalclimatevariabilityandouruneventransitiontoawarmerworldByScottStGeorgeJune21,2023Onco-occurringandcascadinghazardsByDanielBannisterMarch20,2023RecentEventsContactsandInformation4646ContactsandInformationForewordOutlookRecentEventsContactsandInformation4747OurauthorsContactsCameronRyeHeadofModellingResearchandInnovation,WTWResearchNetworkcameron.rye@wtwco.comNeilGunnHeadofFlood&WaterManagement,WTWResearchNetworkneil.gunn@wtwco.comScottSt.GeorgeHeadofWeather&ClimateRisksResearch,WTWResearchNetworkscott.stgeorge@wtwco.comDanielBannisterWeather&ClimateRisksResearchLead,WTWResearchNetworkdaniel.bannister@wtwco.comJamesDalzielHeadofEarthRisksResearch,WTWResearchNetworkJames.dalziel@wtwco.comRossS.Stein,VolkanSevilgen,AliÖzbakirTemblor,Inc.ShinjiTodaIRIDeS,TohokuUniversity,JapanHectorGonzales-HuizarCISESE,MexicoFrancescoSerinaldi,ChrisKilsbyUniversityofNewcastleJamesDoneNationalCenterforAtmosphericResearchAdamScaife,NickyStringerMetOfficeHadleyCentre,UniversityofExeterDavidB.Stephenson,MatthewPriestleyUniversityofExeterForewordOutlookRecentEventsContactsandInformation4848AbouttheWTWResearchNetworkTheWTWResearchNetworkisawell-established,not-for-profit,award-winningcollaborationbetweenscienceandtheinsurance,financeandriskmanagementsector,goingbackto2006.Long-termpartnershipswithmorethan60researchorganizationsacrosstheworldhelpusconfrontthefullspectrumofrisksfacingoursocieties.Ourmissionistoencourageandsupportinnovativeresearchtogaintheclarityofvisionrequiredtoturnrisksintoopportunities.Weaimtoimproveourunderstandingofawiderangeofrisksandusethisoperationalizedresearchtocraftbetterrisksolutions,helpclientsandsocietybecomemoreresilientandtakeadvantageofsustainablegrowthopportunities.Whilsttheriskandinsuranceindustriescontinuetoevolveandimproveatanastonishingrate,noindividualinstitutionhastheresourcesorbreadthofknowledgetosingle-handedlyanswerallthequestionsaroundthequantificationandmanagementofrisk.Ourlong-terminvestmentinresearchandongoinghorizonscanningcanbringthelatestsciencetoourclients,oftenhighlightingemergingrisksbeforetheymaketheheadlines.Partnershipswithacademiadonotnecessarilymeanlongdeliverytimescales,andinfactthemutualunderstandingbuiltoverthoselong-termrelationshipsallowsustobeveryresponsivetoclientdemands.TheWTWResearchNetworkisorganizedaroundsevenresearchhubs,whichdriveanumberofresearchprogramsandresearchprojects,producingacademicandbusiness-focusedresearchoutputsalongawidespectrum:insights,data,models,peer-reviewedjournalarticles,financialinstrumentsandseminars.Thesesevenspecialismsarelinkedbyourfocusontheinterconnectednessofrisksintherealworld,providinganintegratedviewofrisk.Globalpartners,localexpertiseWedriveresearchwithpartnersinscience,academia,thinktanksandtheprivatesector,combiningspecialistexpertisewithknowledgeacrossourglobalnetwork.Innovative,long-termpartnershipsWeformlong-term,innovativepartnershipswiththeresearchcommunity,andsupportearly-careerscientists.UnderstandingofriskOurpartnershipsidentifyrisks,improvetheirunderstandingandquantificationforthebenefitofourclientsandsociety.TransmissionmechanismOurdedicatedteambringsbestpracticeresearchandevidenceintoourclientproposition:riskmodels,advice,thought-leadership,focusedroundtablesandknowledgesharingevents.ForewordOutlookRecentEventsContactsandInformation4949LearnmoreabouttheWTWResearchNetworkToviewpreviousbrochures,articlesandupcomingeventsvisitourwebsite.WillisResearchNetworkWillisResearchNetwork:TheScienceofManagingExtremesNovember2017WillisResearchNetwork11willistowerswatson.comWillisResearchNetwork:TheScienceofManagingExtremesSeptember201616177_170x225_WRNBrochure.indd116/09/201617:52:57201720182016WillisResearchNetworkWillisResearchNetwork:TheScienceofManagingExtremes2019WillisResearchNetworkWillisResearchNetworkScienceForResilience2020202020212019wtwco.comWTWResearchNetworkAnnualReview2022ScienceforResilience20222023Tosubscribetoourquarterlynewsletterpleasesendusanemailwrn@wtwco.comTheWTWResearchNetworkisanaward-winningcollaborationsupportingandinfluencingsciencetoimprovetheunderstandingandquantificationofrisk,withtheaimtoimprovetheresilienceofourclientsandsocietyasawhole.AnnualReview2023/1wtwco.comWTWResearchNetworkAnnualReview2023ScienceforResilienceForewordOutlookRecentEventsContactsandInformationAboutWTWAtWTW(NASDAQ:WTW),weprovidedata-driven,insight-ledsolutionsintheareasofpeople,riskandcapital.Leveragingtheglobalviewandlocalexpertiseofourcolleaguesserving140countriesandmarkets,wehelpyousharpenyourstrategy,enhanceorganisationalresilience,motivateyourworkforceandmaximiseperformance.Workingshouldertoshoulderwithyou,weuncoveropportunitiesforsustainablesuccess—andprovideperspectivethatmovesyou.Learnmoreatwtwco.com.wtwco.com/social-mediaCopyright©2022WTW.Allrightsreserved.WTW_11025606/23wtwco.com5050ForewordOutlookRecentEventsContactsandInformation