Complexity in Climate Change Manipulation Experiments

Climate change goes beyond gradual changes in mean conditions. It involves increased variability in climatic drivers and increased frequency and intensity of extreme events. Climate manipulation experiments are one major tool to explore the ecological impacts of climate change. Until now, precipitation experiments have dealt with temporal variability or extreme events, such as drought, resulting in a multitude of approaches and scenarios with limited comparability among studies. Temperature manipulations have mainly been focused only on warming, resulting in better comparability among studies. Congruent results of meta-analyses based on warming experiments, however, do not reflect a better general understanding of temperature effects, because the potential effects of more complex changes in temperature, including extreme events, are not yet covered well. Heat, frost, seasonality, and spatial variability in temperature are ecologically important. Embracing complexity in future climate change experiments in general is therefore crucial.