ACACIA is an ambitious interdisciplinary alliance to enhance the resilience of at-risk communities in Sub-Saharan Africa to climate impacts. Focusing on floods in the Greater Horn of Africa and floods and tropical cyclones in Madagascar, we seek to improve the ways climate services are produced, disseminated and used for making short-term and long-term decisions to diminish climate risk. Our strategy is to mitigate five obstacles to climate adaptation: 1) Temporal and spatial mismatches and lack of relevance of climate services; 2) Capacity to implement coping strategies and access to climate services; 3) Governance barriers, including fragmentation of responsibility; 4) Climate change, which can make existing coping strategies obsolete; 5) Lack of evidence on the socioeconomic impacts of climate services. Our consortium is highly multidisciplinary. Social science is strongly represented in our cross-cutting co-production activities, which involve working with peer communities consisting of actors from multiple sectors including policymakers, and community work with 100 vulnerable villages in Madagascar. Our rigorous assessment of the added value of climate services-based interventions in these villages will also be led by social scientists. Climate scientists will steer the co-production of national and regional operational early warning systems and work to enhance the skill of a subseasonal forecast model system. All the partners will be involved in an extensive training and capacity-building programme, which targets vulnerable communities, consortium members including national and regional meteorological services. Our consortium has 14 partners, with strong representation from Africa. It involves actors from all parts of the climate services ecosystem. The reason for mobilising such a broad alliance is to ensure that services and protocols are developed locally, which enables our outcomes to be sustained beyond the lifetime of ACACIA.