Rainfall variability increased with warming in northern Queensland, Australia, over the past 280 years

Abstract

Floods and droughts are hydrological extremes that impact ecosystems, agriculture, and human well-being. These extremes are expected to intensify in a warmer world, although many regions lack the observations needed to place current trends in the context of long-term variability. Here we present a new multi-century record of tropical rainfall based on a multi-proxy approach from northern Great Barrier Reef coral. The robust calibration with instrumental rainfall allows us to quantitatively estimate summer rainfall in northern Queensland back to 1746 CE. We find that as global climate warmed, wet-season rainfall in this region has increased by ~10% since 1750 and the standard deviation (21-yr 1-σ) of wet-season rainfall more than doubled, as rainy years became much wetter, while dry years remained dry. Reconstructed rainfall correlates with El Niño indices and the link to Pacific temperature variability has strengthened as climate warmed, consistent with expected intensification of La Niña-related rainfall.