Projecting climate change in South America using variable‐resolution Community Earth System Model: An application to Chile

Summary

This paper presents high-resolution climate projections for South America using a variable-resolution Community Earth System Model at 28 km resolution over South America and 14 km over the Andes. The authors simulate historical and future climate scenarios, finding broad warming (+3–6°C by 2070–2099) and heterogeneous precipitation patterns that drive significant shifts in climate zones, notably the near-elimination of Andean tundra and a 20% expansion of tropical savannah. For Chile specifically, the study projects substantial cryospheric decline, including earlier snowmelt, reduced snow water storage in the Andes, and fewer frost days—outcomes with potential implications for regional water resources and agricultural systems dependent on snow-fed systems.

Regional applicability

Whilst this study focuses on Chile and broader South America rather than the United Kingdom, the methodological approach—variable-resolution Earth System Modelling to project fine-scale climate impacts on water storage and seasonal climate dynamics—is transferable to UK-relevant questions about orographic precipitation, snowpack changes in Scottish highlands, and agricultural climate resilience. The cryospheric decline and shifts in precipitation seasonality modelled for the Andes may inform thinking about hydrological risks in upland UK farming and water security, though direct applicability to UK conditions is limited.

Key measures

Temperature change (°C), precipitation change, Köppen–Geiger climate classifications, snow water equivalent (mm), peak SWE timing (months), days below 0°C, days with wet-day temperatures below 1°C, tropical rainforest area changes (%)

Outcomes reported

The study projects temperature increases of 3–6°C by end-of-century across South America under RCP8.5 scenario and models heterogeneous precipitation responses and shifts in Köppen–Geiger climate zones. It specifically assesses cryospheric impacts in Chile, including earlier peak snow water equivalent (1–2.5 months), substantial decreases in snow water equivalent (200–1,000 mm), and reductions in frost days and cool wet season days.

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