Investigating the 8 . 2 ka event in northwestern Madagascar : insight from data – model 1 comparisons 2 3 Ny

25 The 8.2 ka event is a well-known cooling event in the Northern Hemisphere, but is poorly 26 understood in Madagascar. Here, we compare paleoclimate data and outputs from paleoclimate 27 simulations to better understand it. Records from Madagascar suggest two distinct sub-events (8.3 28 ka and 8.2 ka), that seem to correlate with records from northern high latitude. This could indicate 29 causal relationships via changes in the Atlantic Meridional Overturning Circulation (AMOC) with 30 changes in moisture source’s δ18O, and changes in the mean position of the Inter-Tropical 31 Convergence Zone (ITCZ), as climate modelling suggests. These two sub-events are also apparent 32 in other terrestrial records, but the climatic signals are different. The prominent 8.2 ka sub-event 33 records a clear antiphase relationship between the northern and southern hemisphere monsoons, 34 whereas such relationship is less evident during the first 8.3 ka sub-event. Data–model comparison 35 have also shown a mismatch between the paleoclimate data and the model outputs, the causes of 36 which are more or less understood and may lie in the proxies, in the model, or in both data and 37 model. Knowing that paleoclimate proxies and climate models produce different sets of variables, 38 further research is needed to improve the data–model comparison approach, so that both 39 paleoclimate data and paleoclimate models will better predict the likely climate status of a region 40 during a specified time in the past with minimal uncertainties. 41 42