Climate extremes are on the rise. Impacts of extreme climate and weather events on ecosystem services and ultimately human well-being can be partially attenuated by the organismic, structural, and functional diversity of the affected land surface. However, the ongoing transformation of terrestrial ecosystems through intensified exploitation and management may put this buffering capacity at risk. Here, we summarise the evidence that reductions in biodiversity can destabilise the functioning of ecosystems facing climate extremes. We then explore if impaired ecosystem functioning could, in turn, exacerbate climate extremes. We argue that only a comprehensive approach, incorporating both ecological and hydrometeorological perspectives, enables to understand and predict the entire feedback system between altered biodiversity and climate extremes. This ambition, however, requires a reformulation of current research priorities to emphasise the bidirectional effects that link ecology and atmospheric processes.

Understanding the processes that shape forest functioning, structure and diversity remains challenging, although an increasing amount of data documents forest systems across scales. Forest models have a long history in assimilating various data and ecological knowledge and can simulate forest dynamics over spatio-temporal scales unreachable by most empirical investigations. Here we describe the trajectories of development different forest modelling communities have followed to demonstrate the leverage that computer models offer for advancing the understanding of forest ecosystems. Using three widely applied but contrasting forest modelling approaches - species distribution models, individual-based models and dynamic global vegetation models - as examples, we show how scientific and technical advances have led models beyond their initial objectives and limitations. We provide an overview of recent model applications on current important ecological topics and pinpoint ten key questions that could, and should, be tackled with forest models in the next decade. This shows that forest models, due to their long history of assimilating empirical knowledge, their iterative and continuous development, and their complementarity, represent an invaluable toolkit to address a wide range of theoretical and applied ecological questions, hence fostering a deeper understanding of forest dynamics, particularly in the context of global change.