Estimating the Role of Natural Variability in Climate Change Using Observations

Abstract:

Large ensembles of climate change simulations provide valuable insight into the role of natural variability in climate change. But they are invariably computationally expensive. In this work we develop a simple analytic expression for the role of natural variability in climate change. The results suggest that the signature of natural variability in future climate can be quantified with a high degree of accuracy from two simple statistics, both of which can be derived from either a control simulation or the observations: the autocorrelation and standard deviation of the unforced variability. The results suggest that the signature of natural variability in future climate can be deduced with a high degree of fidelity from the statistics of the observed climate.