The World Adaptation Science Programme Science-for-Adaptation Policy Brief on Advancing Effectiveness for Climate Adaptation is the seventh issue in the series published by seven United Nations agencies that form the World Adaptation Science Programme (WASP): UN Environment Programme (UNEP), the World Meteorological Organization (WMO), United Nations Framework Convention on Climate Change (UNFCCC), Intergovernmental Panel on Climate Change (IPCC), Global Environment Facility (GEF), Green Climate Fund (GCF), the United Nations University (UNU) and the United Nations Educational, Scientific and Cultural Organization (UNESCO). The Secretariat of the WASP is hosted at UNEP, Nairobi, Kenya. Loss and damage are increasingly mentioned in National Adaptation Plans and National Determined Contributions, but these documents say little about options to address loss and damage and largely miss non-economic loss and damage. How to avert, minimize and address loss and damage is still in question. This issue of the WASP policy brief discusses the foundation on multiple dimensions of the loss and damage, which is induced by inadequate action on climate change. It seeks to answer the following questions: What is the current state of knowledge and recognition of loss and damage in national policy? What are the key science gaps obstructing the effective implementation climate related loss and damage measures? What are the policy gaps and possible mechanisms to better address observed and projected loss and damage?