Results/Conclusions

I present a short review of: 1) species-specific differences in physiological responses, particularly to CO₂ directly; 2) the hidden but likely changing role of extreme events, which have unique attributes; 3) phenomena beyond autecological climatic responses (pollinators, diseases, etc.); 4) genetic responses, including rate limitations, population-genetic constraints, and an expected lack of adaptive genetic variation for responding to elevated CO₂ and associated phenomena that are setting in rapidly on ecological and evolutionary time scales; and 5) limitations in characterizations of driving factors, extending beyond uncertainties in scenarios (CO₂ emissions, land-use change, etc.) and climate model physics, to include fundamental changes in the spectra of extreme events.  I also review some recent progress, such as the JEDI model of stable trait combinations in plant functional types.  I conclude that we need much more species-specific data, improved climate models, new orders of statistics, and an effort to bridge the gap between biogeographic models (emphasizing the abiotic) and theory (emphasizing the biotic).  Nonetheless, we should expect that for several decades, at a minimum, we will be unable to predict major patterns and will have to use post hoc analyses very efficiently.