Climate is an inordinate challenge but also an inordinate opportunity to transform economies onto a low-carbon, resourcee !cient Green Economy path. Catalyzing clean energy will not only cut greenhouse-gas emissions as part of e”orts to limit a global temperature rise to under 2 degrees C or more, it also represents a way of curbing healthhazardous air pollution while o”ering a rapid path to address energy poverty, especially in rural areas of developing economies. Meanwhile enhancing ecosystems such as forests, mangroves and seagrasses in order to conserve their carbon stocks can also trigger multiple benefits from boosting water supplies and improving agriculture to maintaining natural sea defences and nurseries for fish. The 17th Conference of the Parties meeting in Durban, South Africa, later this year presents the world with another opportunity to advance the climate agenda and co-operative action under the UN Climate Convention. It is crucial that those actions are designed within a coherent and robust policy-planning framework to ensure that they are both cost-e”ective and compatible with broader social, economic and environmental goals. For developing countries, sound climatepolicy planning will also enhance access to climate finance from the developed ones. Climate-policy planning is a complex undertaking. Many developing countries are only just starting to consider how to go about it and some require improved access to the requisite knowledge, expertise and technical skills. Drawing upon best practices, tried and tested in other parts of the world, is clearly an advantage. The MCA4climate, a new UNEP initiative, is designed to assist policymakers, particularly in the developing world, in that endeavour. It o”ers concrete guidance and recommendations on a number of critical issues and proposes a formal framework for evaluating climate mitigation and adaptation policies, paving a practical way forward so that countries evolve sustainably and grow their economies in a way that keeps humanity’s footprint within planetary boundaries. It draws on the work of leading experts on climate policymaking from around the world and uses an innovative approach to assessing policies that ensures that climate policies and strategies take full account of developmental concerns and objectives. The MCA4climate initiative reflects UNEP’s mission to provide leadership and encourage partnership in caring for the environment by inspiring, informing and enabling nations and peoples to improve their quality of life without compromising that of future generations—issues at the centre of Rio+20 next year in Brazil as governments look to scale-up and accelerate the implementation of the agreements, including those relating to climate change, established in Rio in 1992.