Current scenarios predict an accelerated biodiversity erosion with climate change. However, uncertainties in predictions remain large because the multitude of climate change effects from genes to ecosystems and their interdependencies are still overlooked. This incomplete vision hampers the development of effective mitigation strategies to sustain biodiversity. Climate change can directly modify the phenotype and performance of individuals through phenotypic plasticity and evolution on contemporary time scales. The microevolution of keystone species can spread throughout the whole ecological network due to changes in species interactions and further translate into an altered ecosystem functioning. Conversely, direct impacts on communities and ecosystems can have ripple effects on the phenotypic distribution and evolution of all species of ecological networks. Climate-driven changes at individual and population levels can shape community composition and ecosystem functioning, and vice versa, altering eco-evolutionary feedbacks, namely the reciprocal interactions between ecological and evolutionary processes. Climate-driven ecological and evolutionary dynamics are yet often investigated separately. The role of eco-evolutionary feedbacks in climate change impacts on biological systems therefore hinges on little concrete empirical evidence contrasting with a profuse theoretical development. ECOFEED will investigate climate-dependent eco-evolutionary feedbacks using a 6 year-long realistic warming experiment reproducing natural conditions and thus allowing for both evolutionary and ecological dynamics to occur under a predicted climate change scenario. Complementary laboratory experiments will quantify reciprocal impacts of climate-dependent evolutionary and ecological changes on each other. ECOFEED will provide unprecedented insights on the eco-evolutionary feedbacks in a future climate and will ultimately help refine predictions on the future of biodiversity.