Climate change scenarios and the increasing severity of thermal extremes in the pampas region

Abstract

This research aimed to analyze the Spatial and Temporal trends and variations of extreme thermal events in the Pampas region (Argentina) over three periods: the present (2009–2023), the near future (2024–2038), and the Far future (2085–2099) under two greenhouse gas concentration scenarios, RCP 4.5 and RCP 8. Across these periods, 14 extreme thermal indices were calculated using maximum and minimum temperature series recorded in situ by 48 meteorological stations. For future projections, we employed two validated climate models: the CCSM4 model (validation index: 0.91) for the humid region and the CNRM-CM5 model (validation index: 0.91) for the central region, selected based on their high performance in representing regional thermal conditions. Results revealed a significant warming trend, with regional maximum temperature increasing by 1.1 °C during 2009–2023, and projections of up to 1.4 °C increase in the Far future under RCP 8.5. A notable Spatial heterogeneity was observed, with Western and central sectors of the Pampas showing more pronounced warming patterns than Eastern coastal areas. Extreme indicators showed pronounced changes: absolute maximum temperature (TXx) increased by 2.5 °C in the present period, with projections of up to 4.9 °C increase by 2085–2099 under RCP 8.5. Warm days (TX90p) increased by 5 days/15 years in the present, with projections of 6.7 days/15 years in the Far future. Concurrently, cold events decreased significantly, with cool days (TX10p) declining by 6 days/15 years in the present and projected to decrease by 7.1 days/15 years in the Far future. This thermal intensification will adversely affect agricultural production, economic development, infrastructure, biodiversity, and public health, heightening the vulnerability of the region’s socio-ecosystems. These findings are critical for developing Spatial management plans and designing climate adaptation and mitigation measures at local and regional scales.