Impact of climate change on surface temperature projections in Colombia’s principal natural regions

Abstract Climate change poses an increasing threat to Colombia, whose five principal natural regions (Andean, Caribbean, Orinoquia, Pacific, and Amazon) exhibit marked climatic and geographical diversity, increasing their vulnerability to rising surface temperatures. Projected temperatures across these regions were evaluated under the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios using an ensemble of NEX-GDDP-CMIP6 models. Eleven models from the NEX-GDDP-CMIP6 set, along with the full ensemble, were assessed for their ability to reconstruct historical temperatures from 1950–2014. An ensemble was subsequently constructed from the 4 top-ranked NEX models that achieved optimal values across statistical metrics. Model selection employed three multi-criteria decision-making techniques: Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS), Multi-Objective Optimization based on Ratio Analysis (MOORA), and Weighted Aggregated Sum Product Assessment (WASPAS). The four highest-ranked general circulation models (GCMs) were CMCC-ESM12, BCC-CSM2-MR, INM-CM5-0, and ACCESS-CM2. Projections of temperature from the resulting NEX-GDDP-CMIP6 ensemble were adjusted for monthly variations using the Quantile Mapping method. In the near future, the Amazon Region is projected to experience the largest temperature anomalies between October and February, with estimated values of 2.5 °C (95% CI:2.1–3.0 °C) under the SSP5–8.5 scenario. The Orinoquia Region is expected to reach the highest anomalies in January with values of 2.6 °C (95% CI: 2.2–3.0 °C) under the same scenario. December is projected to exhibit the highest positive anomalies for the Amazon Region in the far future, with values ranging from 3.0 °C (95% CI: 2.7–3.2 °C) to 4.5 °C (95% CI: 4.2–4.7 °C) across all scenarios. Coastal and topographical factors contribute to projected temperature variability in the Caribbean and Pacific regions. These findings confirm Colombia's high climate sensitivity and underscore the necessity for targeted mitigation and adaptation strategies, particularly in regions characterized by pronounced climate gradients.