Rise in coincidence of extreme heat in Nevada’s largest urban areas

Abstract

As global and regional temperatures rise, urban areas are increasingly vulnerable to heat-related impacts because of high-density populations and anthropogenic alterations to the landscape. The urban heat island (UHI) effect enhances human and environmental exposure to heat. This exposure produces human health impacts, damages ecosystems, increases water and energy demands, and strains infrastructure. Here, we assess warm season urban heat extremes in four Nevada (western USA) cities using daily temperature data between 1950-2018. Extreme heat days (nights) are defined as days when maximum (minimum) temperatures exceeded the 90th percentile of the 1981-2010 baseline. While all locations observed more frequent coincident heat extremes in the past five years, the two most urbanized cities (Las Vegas and Reno) have strong correlations between coincident events and extreme heat nights. This suggests a role for UHI effects as both cities have undergone increases in minimum temperatures. To aid Nevada cities in actively preparing climate change resilience and adaptation plans, we have identified a range of mitigation and adaptation strategies aimed at reducing negative effects from increasing regional and local temperature extremes.