Palaeoclimate studies relevant to natural resource management in the Murray-Darling Basin

Abstract

1. Australian palaeoclimate researchers have generated much data and published many studies relating to climate change and variability across south-eastern Australia and how such changes have affected landscapes, vegetation cover and waterways. These studies have used records of change from a range of resources including speleothems, tree rings, river channels and terraces, dune systems and lake sediments. A suite of biological, geological and chemical indicators have been used to infer system responses to past climate changes. 2. To date, many of these studies have focussed on the understanding of local climate change and system responses, or how local records relate to regional, global or orbital drivers of change. The purpose of these studies has been to examine change per se. These studies have rarely therefore, been tailored with the intention of generating data to inform policies aimed at improving natural resource management and developing an interactive dialogue with natural resource managers to explore the benefits of palaeoclimatic data in informing natural resource management. 3. Available scientific evidence reveals that the Murray-Darling Basin has experienced considerable climate change at a range of timescales. Over the last few hundred years (and during the time of European settlement) the MDB has been subjected to extended inter-decadal variability, known as flood and drought dominated phases, and year-to-year ENSO variability. Whilst natural systems have been resilient to historical changes, a recent, statistically significant step change toward regionally drier conditions comes at a time when the system is severely stressed by anthropocentric activities, especially from agriculture, water regulation and decisions regarding landscape restoration or revegetation. 4. Future climate change scenarios suggest a high likelihood of increased temperatures and less effective rainfall across much of the MDB. If the duration of the recent step change extends as long as those past, future climate will be the critical factor influencing natural resource management and policy considerations within the MDB. 5. A clear opportunity exists to consolidate a network of policy-relevant palaeoclimate researchers and a portfolio of research tailored at informing natural resource managers of the MDB.