Porto Alegre sits where five tributaries meet the broad Guaíba estuary. That geography is why the city has long managed flood risk as an ordinary municipal responsibility. It is also why the principal airport serving the state, Salgado Filho, is exposed to hydrological extremes and potential operational disruption. The airport is a commercial and logistical hub with a single main runway and dense surface-access links that concentrate exposure at ground level.
The climate science is unambiguous about the direction of travel for heavy precipitation and pluvial flooding across southern South America. Observed increases in extreme rainfall and projections of more intense short duration events mean that airports in flood-prone locations will see elevated frequency and severity of inundation risk. For aviation stakeholders this does not present only a weather problem. It is an infrastructure, contractual and regulatory problem.
Academic and sectoral assessments that map climate exposure to airport assets show two recurrent vulnerabilities. The first relates to inundation of airside surfaces, low-lying terminals and critical services such as electrical rooms, fuel farms and ground handling areas. The second is operational: even limited water on aprons or taxiways, or loss of electrics and air traffic support systems, can force prolonged suspension of services with outsized economic consequences. These patterns are well established in comparative assessments of major airports worldwide.
That reality has regulatory and contractual implications. Concession agreements, operating licenses and national aviation safety rules typically treat severe weather as an operational contingency. They rarely, however, mandate investment or performance outcomes for climate resilience informed by forward looking climate science. Where contracts do not require adaptation measures they risk leaving taxpayers and passengers to pick up reconstruction and service-recovery bills after a closure. The aviation sector can and should change that allocation of risk through clearer regulatory requirements and contract terms.
Practical measures that regulators and airport authorities can require now fall into three categories. First, make resilience part of the baseline design and operations. That means requiring that all new critical assets be sited or elevated above a formal design flood elevation, that substations, backup power and fuel supplies are protected with floodproofing, and that drainage and pumping capacity be sized for updated rainfall intensities rather than historical averages. Industry guidance and case studies provide concrete templates for these actions.
Second, harden governance and contracts. Concession agreements should include mandatory climate risk assessments, scheduled reassessments tied to changing climate projections, and clear rules on who pays for adaptation when a foreseeable climate risk materializes. Force majeure clauses must not be a free pass for underinvestment. Regulators should require insurance and escrow arrangements to ensure rapid repair and to protect continuity of essential services. These are legal fixes with material operational effects.
Third, mandate operational contingency planning across the network. A single city closure should not sever regional connectivity. That means preapproved alternative airport arrangements, tested passenger-transfer workflows, interoperable NOTAM and passenger-communications protocols, and arrangements with military or general aviation fields to handle diverted flights when needed. Interagency drills with civil defense, port authorities and municipal services must be part of any credible resilience plan. EUROCONTROL and ICAO documents underline the value of networked contingency planning rather than ad hoc local responses.
Policy makers in Brazil and elsewhere should also recognise the equity and economic stakes. Airports are lifelines. Their closure disrupts medical transfers, cargo supply chains and tourism and places disproportionate burdens on businesses that cannot absorb extended interruptions. For regions with a dominant airport serving wide catchment areas, the systemic economic cost of closure justifies public investment in resilience as a form of risk pooling. That can be structured through targeted grants, tax incentives for resilience upgrades, or by conditioning public support on robust resilience planning in concession contracts.
Finally, transparency and oversight matter. Governments should require publication of climate risk assessments, resilience plans and progress against milestones. Civil society and local governments must have access to technical information so that land use, floodplain management and critical infrastructure siting are coordinated, not contradictory. Aviation regulators should set minimum resilience standards and monitor compliance as a safety and public-interest function.
Porto Alegre is not unique. Airports worldwide face similar pressures. The regulatory response is a choice. Treating airports as climate critical infrastructure means moving beyond emergency response to proactive planning, contractual reform and investment. For lawyers and policy makers that is a clear work program: update standards, close contractual gaps, require resilience by design and test the network under realistic stress. The alternative is to accept episodic closures as the new normal, with the attendant social and economic costs borne by citizens rather than apportioned through durable regulatory fixes.