Agricultural Drought Indices - US Department of Agriculture

Figure 1. Monthly rainfall variability at Bowen, North Queensland.
The Federal National Drought Policy (NDP) (Australia Parliament 1992) was accompanied by
State Drought Policy initiation with a key emphasis in both state and federal jurisdictions on the
utilization of an improved understanding of the science aspects of droughts, including return
periods, severity, and access to useful seasonal forecasting to better prepare for drought—all with
a strong focus on aspects of self-reliance. In this respect, the NDP provided three objectives: “(1)
to encourage primary producers and other segments of rural Australia to adopt self-reliant
approaches in managing for climatic variation, (2) to facilitate the maintenance and protection of
Australia’s agricultural and environmental resource base during periods of increasing climatic
stress, and (3) to facilitate the early recovery of agricultural and rural industries to levels consistent
with long-term sustainable production” (Australia Parliament 1992, White and Walcott 2009). As
White and Walcott (2009) maintain, “all three objectives require comprehensive, but not
necessarily identical, methods for monitoring and assessment to successfully reduce the effects of
droughts” (Australia Parliament 1992, White and Walcott 2009). It is against this framework that
the application of agricultural drought indices is explored as the aim of this chapter.
Thus, “risk management” became a common-place term in Australia, focusing on objective,
science-based decisions associated with improved preparation for drought. To further assist
farmers and agricultural communities, as well as those providing exceptional drought relief
assistance, the term “safety-net” also became common parlance to emphasize that governments
recognized that it was almost impossible to prepare for extreme drought events such as 1 in 20 or
1 in 25 year events, although some state governments, such as Queensland (Department of
Primary Industries, Queensland 1992), aimed to provide some assistance for 1 in 10 year events:
all so-called “exceptional circumstances.” Aspects related to inputs of science, agronomy, and
mathematics (drought frequency distributions) were highlighted in order to assist drought policy
and the implementation of drought policy in Australia, particularly since 1992.
Science issues have also come to the fore in policy and operational discussions regarding what
“drought”—or especially “exceptional drought”—actually is, and it is within this context that
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