A holistic approach – instead of tackling problems incrementally – must play a pivotal role in the climate transition. Transitioning to a low-carbon economy requires multifaceted strategies that encompass pricing, planning, regulation and institutional mechanisms. Current approaches are not mobilising sufficient action and investment. We highlight the importance of leveraging all sources and instruments, including public funds, private investments, carbon markets and philanthropy, to fill the climate finance gap and seize the huge opportunity to support economic development and promote climate stability. We introduce the idea of the “mitigation avocado”, where individual projects are complemented by infrastructure, institutions and regulations that create an improved investment environment, and a large-scale systems approach ensures integrity in rewards for change observed at the system level. We suggest that holistic approaches and large-scale international carbon market agreements can jointly mobilise private finance and unlock the potential capacity of the global south for climate action and sustainable development.