Southeast Asian experts have warned that climate resilience has become an economic necessity as increasingly extreme weather threatens cities, infrastructure and regional competitiveness. At a meeting in Bangkok, panellists said that the Association of Southeast Asian Nations (ASEAN) infrastructure and planning systems were designed for climate conditions that no longer exist. Thailand illustrates the challenge, with erratic rainfall, expanding cities and fragmented water management involving around fifty government agencies. Experts advocated better coordination, improved data sharing, and AI to strengthen forecasting and decision-making. They urged planners to regard waterways, trees and soil as essential infrastructure, using natural systems alongside conventional engineering to reduce flooding and extreme heat. Greater cooperation between countries is needed, because rivers, coastlines and supply chains cross national boundaries. The speakers also called for stronger local involvement, better access to international climate finance, and greater recognition that investment in resilience can generate economic benefits while protecting communities from increasingly severe disasters.