Despite the extensive portfolio of interventions to protect health against climate change, the evidence base for their effectiveness remains surprisingly weak[1]. Of the 1,682 articles on climate adaptation, only 99 looked at specific health interventions in low- and middle-income countries, and only two included a formal comparison group evaluation to demonstrate causality[1]. Researchers and funding institutions therefore have an urgent task to close this gap between theory and evidence[1]. Priority is given to randomized controlled trials of climate adaptation interventions with clearly defined health outcomes and robust quasi-experiments using modern methods of causal analysis[1]. National and local governments urgently need more evidence on the effectiveness, desirability and value of individual measures when developing climate change adaptation and health plans[1]. Effectively protecting populations from climate-related health risks requires a portfolio of complementary behavioral, environmental, public health and policy interventions[1].