Projected increase in continental runoff due to plant responses to increasing carbon dioxide.

In addition to influencing climatic conditions directly through radiative forcing, increasing carbon dioxide concentration influences the climate system through its effects on plant physiology. Plant stomata generally open less widely under increased carbon dioxide concentration, which reduces transpiration and thus leaves more water at the land surface. This driver of change in the climate system, which we term 'physiological forcing', has been detected in observational records of increasing average continental runoff over the twentieth century.

Inference in ensemble experiments.

We consider inference based on ensembles of climate model evaluations, and contrast the Monte Carlo approach, in which the evaluations are selected at random from the model-input space, with a more overtly statistical approach using emulators and experimental design.