Robust spatial changes in climate classes: insights from bias-corrected CMIP6 models across Chile

Abstract The climate in Continental Chile is marked by strong latitudinal and elevation gradients, exacerbated by diverse geographical features, such as the Andes. Despite previous studies projecting warmer and dryer conditions for most of the territory, there is concern about the robustness (i.e. level of agreement among models) of changes projected for its magnitude, not only for the impact on climate indices across this domain but also to identify changes in the spatial distribution of climate classes. Hence, we statistically downscaled and bias-corrected daily CMIP6 model outputs for continental Chile, using a multivariate bias correction method, to project climate changes under the SSP5-8.5 scenario. The results reveal that General Circulation Models (GCMs) project increased dryness across the study domain by the end of the 21 st century, especially in Central Chile (−30% in precipitation), with notable sensitivities of precipitation projections to the implementation of bias correction methods in the northern and austral macrozones. Temperature projections show less dispersion, with higher increments in northern Chile and the Andes (4 ∘ C–5 ∘ C). Notable shifts in the extension of Köppen–Geiger climate classes are projected for the next decades, with the expansion of deserts in northern Chile and the prevalence of temperate climates with dry summers in central Chile. The Andes subdomain is expected to face the most dramatic changes in Köppen–Geiger classes (inter-model agreement <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo>&gt;</mml:mo> </mml:mrow> </mml:math> 70%). Surprisingly, despite the large spread in GCM projections, there is high agreement among models regarding spatial changes in climate classes. Additionally, our results project drastic reductions in snowfall across the Andes, with higher freezing level heights that may exacerbate flooding and landslide risk across the country.