Global thermal bioclimate indicators: spatial shifts and temporal changes

Climate change is inducing worldwide alterations in temperature patterns, impacting biotic ecosystems. This study conducts a comprehensive spatiotemporal examination of global thermal bioclimate indicators from 1941 to 2020, using high-resolution ERA5 reanalysis data. The research aimed to evaluate the global climatic shifts in the recent decades compared to a 1941–1980 baseline. To this end, Sen’s slope estimator and the modified Mann–Kendall test to analyze trends in eleven bioclimatic indicators (BIOs) on a global scale. The findings reveal a widespread warming with significant regional variability. A general global warming trend was observed, with polar regions experiencing the most temperature increases, often exceeding 2.5 °C over the study period. Strong polar amplification was particularly observed in Arctic areas, where warming rates reached up to 0.6 °C per decade. The study also identified trends toward more extreme and variable temperature conditions, with maximum temperatures of the warmest month (Bio-5) increasing by 1 °C to 3 °C in many regions. Moreover, decreases in the diurnal temperature range (Bio-2) were observed across numerous areas, with some regions showing changes of up to 1.2 °C. The research further reveals heterogeneous patterns in temperature seasonality (Bio-4), with some northern areas experiencing up to 80% decreases in this metric. These changes affect biodiversity, ecosystem dynamics, agriculture, and human health, highlighting the urgent need for continued monitoring and research to address the global challenges of changing thermal conditions.