全球变化知识资源中心

To the Editor —

Uncertainty in climate predictions, and especially in tipping-points towards dangerous climate change, is not only a challenge for science communication¹ but also for triggering collective action as outlined by Barrett and Dannenberg².

Uncertainty is a measure of unexplained variation, and can be partly caused by measurement errors, and partly by our lack of understanding about cause and effect. But predictions of climate change, and approaches to its mitigation, do not only carry uncertainties in the magnitude of responses, they also entail significant natural variability in time and space³. Importantly, this spatial and temporal variability will not shrink with scientific progress. Embracing the difference and clearly distinguishing between these two sources of variation is therefore critically important for science communication as well as for collective and policy action (see Fig. 1).

Progress in science will decrease uncertainty (though probably not eliminate it), but will not decrease total variation.