Through this case study, two leading international museums have shared how they are adopting a structured, leading-practice approach to embed climate action and sustainability into organisational strategy and planning, set meaningful objectives and actively engage the community through programming and curation. While it is too early to gauge the full impact of their current action plans, the strategic and holistic way in which they are integrating sustainability -- and the SDG targets -- into ways of working marks a shift in museum practice. No two institutions are exactly alike and each must chart its own sustainability leadership path, but among the signature elements underpinning the approach these museums have taken are the following: - Mapping at the outset the organisation's role and contribution within the 2030 Agenda, Paris Agreement and other pressing societal challenges; - Proactive early involvement of stakeholders in the design and strategic intent of the plan via the creation of steering committees, rollout of employee surveys and community consultation; - Identification of material topics and setting of strategic objectives across priority impact areas; - Development and endorsement of Specific, Measurable, Achievable, Relevant and Timebound (SMART) organisational targets, with roles and responsibilities; - Measuring and reporting publicly on progress and performance to hold the museum accountable and contribute to the conversation. The five steps of the Universal Strategy Cycle (see Fig. 1.) are a journey any museum can take at any stage of sustainability leadership maturity to realise its 'full transformative potential' for sustainable development and become an ally in 'facing the common threat of climate change', as advocated by ICOM (2022, n. page). As these museums continue to make progress on their plans and 'get their house in order, emphasis is likely to shift from mitigation and management of operational impacts towards greater engagement and partnership to spur the deeper cultural changes that humanity - and the planet -- so urgently needs. One key takeway from the experience of the AM and Powerhouse is that it is essential to start measuring impacts and set plans to minimise these. There is much to learn from other industries and institutions, and there are many solutions at hand to reduce negative impacts and enhance positive influence. Pulling together a cohesive approach lifts standards of operating and supports the organisation through these changes. As climate-related emergencies increase in scale and size, cultural institutions will probably be among the first to be defunded so they have to play a more active role in helping the public, talking about the crisis and flagging solutions. Museums are well-placed to teach on adaptation and resilience and whatever their niche area, they can weigh in on what building for the future looks like. Our sincere call to action is to be courageous, take risks, be vulnerable and know there will be criticism. Connect with others and don't try to do it on your own. To unleash the transformative power of culture, museums must play a part in reimagining a better version of the world, together. If this seems hard, remember that creating cultural change is actually the easy part. Living with climate change is much harder. [ABSTRACT FROM AUTHOR]