Territorial Stress Index (TSI): A Spatial Approach to Climate Change in Gran Canaria, Spain and Its Implications for Emergency Management

Climate change does not manifest homogeneously across a territory, especially on oceanic islands where the complexity of the terrain can generate significant climatic gradients over short distances. This study analyzes the spatial evolution of maximum temperature (TMAX) and precipitation in Gran Canaria during the period 1991–2025 and explores its implications for land use planning and emergency management. For this purpose, homogenized monthly series from Spain’s State Meteorological Agency (AEMET) were used, analyzed on the basis of a sectorization of the island into seven climatic zones and the use of different statistical procedures for estimating and contrasting trends. Additionally, an exploratory Territorial Stress Index (TSI) was developed to synthesize the relative intensity of thermal and pluviometric change. The results show a generalized and statistically significant warming, although with significant spatial differences, while precipitation exhibits greater heterogeneity and shows no significant trend for the island as a whole. At the climatic zone scale, TMAX trends range between 0.149 and 0.408 °C per decade, while precipitation trends vary both in magnitude and direction. The highest TSI value (90.0) was obtained for the leeward mid-slopes, where intense warming coincides with a reduction in precipitation, creating a warming–drying scenario. Other areas with relatively high values exhibit warming–wetting configurations, indicating that climate stress does not follow a single territorial trajectory. The TSI does not constitute a risk index but facilitates the identification of spatial differences in the evolution of climate stressors that can serve as a basis for subsequent assessments incorporating hazard, exposure, vulnerability, and response capacity. These results highlight the importance of incorporating intra-island climate differentiation into adaptation strategies, land use planning, and emergency management.