A new manual that will enable policymakers to calculate the true value of ecosystems for a transition to a green economy across the world's 52 small island developing states (SIDS), was launched by the United Nations Environment Programme (UNEP) at a ceremony celebrating the end of the International Year of SIDS. The manual highlights the strong interdependency between the natural environment and the economy of SIDS and the importance of accounting for the contribution of ecosystem services to human well-being in order to be able to quantify and manage those benefits. The Guidance Manual on Valuation and Accounting of Ecosystem Services for Small Island Developing States is seen as a timely and critical tool for mainstreaming island ecosystem services in conventional economic decision-making frameworks, and ultimately supporting policymakers' ability to achieve sustainable development.