This category addresses both the resilience of WASH systems under climate stress and the role of WASH in climate mitigation. Subthemes include flooding, drought, heat, extreme weather, infrastructure vulnerability, service continuity, circular sanitation, wastewater reuse, energy and nutrient recovery, and lower-emissions sanitation pathways. Research areas include comparing sanitation technology performance under climate stress; identifying climate vulnerability hotspots; incorporating climate-risk metrics into sanitation investment planning; testing low-energy and resource-recovery approaches; and estimating the adaptation and mitigation value of sanitation and wastewater interventions.