Seasonal temperature and rainfall extremes 1911–2017 for Northern Australian population centres: challenges for human activity

Abstract

More than 40% of the human population reside in global tropical zones despite the extreme climates that frequently approach the upper thermotolerance levels for human physical activity and societal flourishing. Many of these regions also regularly subject resident populations to extreme weather events. Australia’s tropical regions experience exceptionally high climatic variability, making it one of the world’s most challenging for human settlements. Adaptation planning, project management and health protection agencies working at local scales require localized analysis on long-term climatic trends and projections. Utility of existing large-scale analyses is constrained by climatic heterogeneity across expansive national scales. Here we track historical changes in seasonal climatic extremes for seven key population centres across Australia’s north between the periods 1911–1940 and 1988–2017 as measured against the 1961–1990 period. Shifts in daily minimum temperature (20 °C or more), maximum temperature (10th, 90th and 95th percentiles), trends in heatwaves (5 days or longer) and in 1- and 3-day heavy rainfall events (95th and 98th percentiles) are provided. Results indicate the greatest warming has occurred during the Dry season and in coastal locations. Rainfall extremes demonstrate a pattern of marked spatial non-uniformity. This location-centred approach to identifying shifts in climatic extremes has wide applicability for adaptation planning across diverse global climatic regions.