In their section on 'Weather and climate change drivers', Huntingford et al.1 propose various driving mechanisms for the record precipitation that caused flooding in southern England in the winter of 2013/14: the North Atlantic Oscillation (NAO), Atlantic Multi-Decadal Oscillation (AMO), Indonesian precipitation via cold weather in North America, the Quasi-Biennial Oscillation (QBO), Arctic sea ice, and solar activity (sunspots). One would expect evidence for these drivers to be apparent in the historical record if they played a significant role in driving a single year's record seasonal mean precipitation. However, past data reveal only weak associations (linear and nonlinear) between each of these drivers and precipitation in southern England, where all of the notable floods occurred (Fig. 1). Most of the correlations are small and not significantly different from zero at the 5% level (far right column) and the smooth non-linear fits (bottom row) have confidence intervals that could easily include horizontal lines showing no effect on precipitation for all values of the predictor.
GJ van Oldenborgh, DB Stephenson, A Sterl, R Vautard, P Yiou, SS Drijfhout, H von Storch, H van de Dool. Drivers of the 2013/14 winter floods in the UK
published, Nature Climate Change, 2015, 5