Key findings from the Indian Ocean Climate Initiative and their impact on policy development in Australia

Abstract

Since the mid-1970s the climatic changes that have taken place in southwest Western Australia have generated a variety of impacts, the most prominent of which is a reduction in dam inflows of at least 50 percent. These impacts were the catalyst for the formation of the Indian Ocean Climate Initiative in 1998, a research partnership between two national research organizations and several state government departments and agencies. This paper describes the key scientific findings of the Initiative with respect to the nature of the climatic changes that have taken place within the region, explores the factors that might have caused these changes, and describes the most recent climate projections for the region. We reflect on the factors leading to the rapid acceptance of the research outcomes from the Initiative, the impact of the Initiative on policy development across Australia and its likely evolution post-2006.

Sudden forest canopy collapse corresponding with extreme drought and heat in a mediterranean-type eucalypt forest in southwestern Australia

“…Many dominant tree species within MTFs in the South-West of Western Australia (SWWA) have shown similar symptoms in recent decades (Archibald et al 2005;Auclair 1992;Hooper 2009), corresponding with a long-term decline in rainfall (Fig. 1a) (Bates et al 2008). Despite this, large-scale tree mortality resulting from sudden and severe drought has largely not been observed until this point.…”

“…1b). Meanwhile average temperatures have risen at a rate of 0.15°C per decade over the same time period (Bates et al 2008). The long-term drying and warming trends culminated in a record dry (40-50% below average rainfall) and hot year in 2010, made possible by a record dry summer (DecemberFebruary), winter (June-August), and below average spring (September-November) rainfall (BOM 2011a).…”

“…Formerly perennial streams are now ceasing to flow for considerable periods each year (Petrone et al 2010), while groundwater levels have fallen up to eleven meters in some regions since 1975 (Croton and Reed 2007). and 1970-2011 illustrating a climate shift described in Bates et al 2008 Corresponding with a prolonged heatwave (nine days greater than 35°C) in late February 2011(BOM 2011b) midstorey and overstorey tree crowns suddenly began dying (collapsing) in several ecosystems in SWWA (Matusick et al 2012). This paper addresses the recent canopy collapse in the Northern Jarrah Forest (NJF) and aims to: 1) estimate the incidence (spatial scale) and severity of canopy collapse across the NJF; 2) define associations between canopy collapse and forest stand variables; and, 3) investigate the variation in crown collapse and regrowth in relation to tree species and size.…”

Fire‐stimulated reproduction in the resprouting, non‐serotinous conifer Podocarpus drouynianus (Podocarpaceae): the impact of a changing fire regime

“…Modelled future climates within the region (Bates et al 2008) project a decline in rainfall and an increase in temperature. These climate shifts will result in increasingly prevalent severe fire weather conditions, increasing the likelihood of ignitions, with more frequent fires over a longer fire season (Bradstock et al 2002).…”

Environmental change: prospects for conservation and agriculture in a southwest Australia biodiversity hotspot

“…A decrease in rainfall since the 1970's has been attributed to far fewer troughs and more high-pressure systems across the region (Hope 2006, Timbal et al 2008, Hope and Ganter 2010. It is difficult to determine whether this is due to natural variability (Cullen and Grierson 2009) or anthropogenic forcing through land clearing or increased greenhouse gases (Bates et al 2008), but part of the change can be attributed to the enhanced greenhouse effect (IOCI 2006, Bates et al 2008. Although rainfall has already decreased in the western part of the SCR, rainfall in the central part is unchanged (Australian Government 2015).…”