The ineffectiveness of climate predictions and what to do about it: the case for storyline
Consider two statements for a past extreme flood event: 1) climate change has increased the precipitation sum over 4 days in a 1000x1000 km2 area by 10% from 60 to 66 mm, approximately following the moisture increase as given by the Clausius-Clapeyron (CC) relation (7% per degree), and 2) climate change has increased peak rainfall amounts within the flood in two days by 20% from 300 mm to 360 mm – an increase beyond the CC rate also called super CC behaviour. Both statements are valid and use peer reviewed methods. The first statement is derived from typical predictive climate model simulations using relative low resolution (blurred) climate simulations; the second statement is derived from conditional storyline simulations in which the flood event is simulated in fine detail for different climate conditions. In this talk I will discuss the evidence for super CC behaviour of rainfall peak amounts. I will also focus on the limitations of typical top-down climate predictions – low resolution, low signal-to-noise and mixing of fundamentally different uncertainty types – and show that conditional, bottom-up developed storylines could complement common predictive systems in helping us to understand and to adapt to climate change and provide more powerful messages to the general public.
Geert Lenderink works at the Royal Netherlands Meteorological Institute on regional climate modeling and the development of climate scenarios. He is mainly interested in the response of convective precipitation to global warming and is/has been involved in many national and European projects about climate change and climate change adaptation.
Moderation: Iris de Vries