It is strongly predicted that warming tropical climates of the 21st Century will push tropical ecosystems, which currently reside at the edge of bioclimatic life zones, into novel states that have no-analog communities. As the climate system warms, tropical forests will be exposed to unprecedented warmer temperatures than those currently found in these biomes. Shifting precipitation patterns will place some tropical forest regions under drought conditions that reduce carbon assimilation and lead to vegetation dieback. Intact tropical forests are a major sink for atmospheric CO2, accounting for up to 50% of terrestrial carbon uptake. Yet, the response to global change, land-use change, carbon-climate feedbacks, and nutrient limitation will contribute to large uncertainty in the stability of this carbon sink over the next 100 years. In addition, most ecological models are parameterized and structured based off of modern observations, which may lead to failure in predicting ecological response to novel climates. Therefore further uncertainty resides in our ability to model tropical forest response to novel climates. Tropical forests are responsible for multiple biases in Earth System Models (ESMs), which result in large disagreements in the future signal of tropical forests acting as a carbon source or sink. Taking a critical look at the research priorities needed to improve representation of tropical ecosystems in models is vital to decrease uncertainties in representing future no-analog communities. This session will focus on collaborations and science feedbacks made between process/experimental scientists and modeling scientists that share an interest in advancing the understanding of tropical ecosystem novel states. This session will include studies focused on model uncertainty and evaluation of modeling biases, which can then be used to inform and develop field experiments. This “Modex” framework (i.e. model-experiment) can be a strong tool for improving predictive understanding of tropical ecosystems and climate feedbacks, while informing the development of next generation modeling science. This session will compliment and benefit the newly developed Next Generation Ecosystem Experiment-Tropics (NGEE-Tropics), which is a 10-year project to dramatically reduce uncertainty in ESM projections, and increase the scientific understanding of how tropical forest ecosystems will respond to climatic change. We propose to explore field sampling techniques, experimental and manipulation projects, remote sensing, and datasets that can inform and validate models, all towards reducing the uncertainty of ecological processes under novel tropical climates.