Irrigation and drought in a southern Australian climate that is arid, variable and changing

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1 Irrigation and drought in a southern Australian climate that is arid, variable and changing Peter Hayman and Mike McCarthy SARDI climate & SARDI viticulture

2 Drought vs Aridity Drought is a mismatch between agriculturists expectation of the climate and the climate at that time. A principal of drought policy is not to confuse drought (temporary dry spell) and aridity (a dry region or season) Drought vs drying; cycle or trend; climate variability or climate shift.

3 Roger Jones CSIRO

4 What destroyed the sand castle? In a variable and changing climate it will always be hard to distinguish between events (wave) and trends (tide) Detection & Attribution studies vs vulnerability studies

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8 Source: CSIRO Irrigation in Perspective 2005

9 Charleville Warrego QUEENSLAND Balonne Border Brisbane Bourke B arwon Moree SOUTH AUSTRALIA Meninde La kes Darling Menindee NEW SOUTH WALES Macquarie Dubbo Morgan Ade laide Lake Vi ctoria Murray Bridge M ildu ra Mu rray Swan Hill Fo rbes Lachlan Murrumbidgie Canberra Albury Sydn ey VICTORIA Melbourne 200 km

10 Collision of calamities Karlene Maywald Nov 2009 More than a third of SA's River Murray food bowl is vacant as grinding drought, low commodity prices, a high Australian dollar, cheap imports and a wine glut force irrigators to cut back on plantings or simply walk off the land. Wine tax + Horticulture wages

11 The first irrigation drought Productivity commission High value horticulture were struggling for the first time ever with insufficient water to produce a crop Horticulture Australia described the deepening crisis for the lower Murray Darling Basin as an unprecedented process of unplanned structural adjustments on a massive scale with consequences for growers, farming families, local businesses and regional communities.

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13 4 Overlapping Phases Pioneering phase, when government built irrigation schemes so that farmers could battle the arid climate with irrigation and just produce. Production phase when farmers were asked to use the climate and irrigation as resources to produce more. Productivity phase when the emphasis was on managing irrigation and the variable climate to produce more efficiently. Persistence or sustainability phase when farmers were asked not only to produce more, produce it more efficiently, but also asked to manage the irrigation and variable and changing climate to produce more carefully.

14 Pioneering Phase To secure to the agricultural population of arid districts a permanent prosperity, it would be through irrigation Deakin 1850 Every spare penny should be spent on water conservation and irrigation, in sinking tanks and putting down bores, in locking our thousands and thousands of miles of rivers.. where oceans of water waste away after each flood. To attend to these things is a national work, for the benefit of the whole nation; to neglect them is a national crime it is suicidal. Henry Lawson Cited by Water4Food

15 PRODUCTION PHASE Make the dessert bloom Nemani et al 2003 Science (6 June 03)

16 Nemani et al 2003 Science (6 June 03) High radiation, warm temperatures, no rain Light textured soils just add water

17 Productivity Phase produce more efficiently Expansionary phase when water is plentiful and cheap, government develops infrastructure and maintenance costs, rising water tables and salinity are over horizon Mature phase rising costs, competition amongst users, introduction of new users and heightened awareness of externalities

18 Source: CSIRO Irrigation in Perspective 2005

19 Water Use Efficiency Off farm and on farm conveyance efficiency (expensive and part illusionary) Field irrigation application efficiency (spray $2000/ ha and drip $5000 ha) Transpiration efficiency (Irrigation scheduling) Harvest index (quality issues in high value horticulture)

20 Value of ML of water Irrigating pasture < $100/ML, Rice, dairy & irrigated wheat $200/ML Cotton > $500/ML Fruit, nuts and grapes $1700/ML Vegetables $3000/ML Summer of 2007/8 lowest rice harvest ever and 4 th highest grape harvest

21 Efficiency and Resilience 1. Perennial Horticulture highly efficient but needs continuity of supply 2. A system that has been tightened in past decades has less slack 3. Very high irrigation efficiency can lead to root zone salinity

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23 Increase in average night temp by 1 or 2 degrees Increase in average day temp by 1 or 2 degrees Changes to temperature Decrease in extreme min temp events - frosts Increase in extreme min temp events - frosts Increase in heat waves Decrease in annual rainfall by 15% Decrease in winter rainfall by 15% Decrease in spring rainfall by 15% Decrease in summer rainfall by 15% Decrease in autumn rainfall by 15% Increase in the intensity of rainfall Changes to rainfall Decrease in vol of surface water Decrease in quality of surface water Decrease in vol of ground water Decrease in quality of ground water Changes to water Increase in soil salinity Changes to soil Lower impact Higher impact

24 October to April Growing Season Temperature Degrees C

25 Greg Jones Degrees C

26 Degrees C D10 D9 D8 D7 D6 D5 D4 D3 D2 D

27 Degrees C D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 Mildura

28 C 1C 1.5C Degrees C D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 Hayman & Alexander

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30 What can we learn from managing our current variable and changing climate for the future variable and changing climate Roger Jones CSIRO

31 Vulnerability/resilience of wine grape growing 140 year old shiraz vines Photo: Wine and Brandy Corporation

32 Howden et al 2010

33 Planning for an uncertain future. Plan for major step change in rainfall (> 15% decline in rainfall) Plan with assumption that variability dominates early stages of CC 5% to 10% redn

34 Planning for an uncertain future. Step change in rainfall to much drier regime > 15% decline in rainfall Plan for major step change in rainfall (> 15% decline in rainfall) True Positive Plan with assumption that variability dominates early stages of CC 5% to 10% redn False negative Variability dominates over coming decades < 10% decline in rainfall False positive True negative

35 Planning for an uncertain future. Step change in rainfall to much drier regime > 15% decline in rainfall Variability dominates over coming decades < 10% decline in rainfall Plan for major step change in rainfall (> 15% decline in rainfall) True Positive Major upheaval but more orderly change. Winners are early adopters of proactive transformational change Plan with assumption that variability dominates early stages of CC 5% to 10% redn True negative Winners are those practicing adjustment change or transformational change to non climate factors

36 Planning for an uncertain future. Step change in rainfall to much drier regime > 15% decline in rainfall Variability dominates over coming decades < 10% decline in rainfall Plan for major step change in rainfall (> 15% decline in rainfall) True Positive Major upheaval but more orderly change. Winners are early adopters of proactive transformational change False positive False alarm leading to expensive & unnecessary transformational change Negative impact on comunities Plan with assumption that variability dominates early stages of CC 5% to 10% redn False negative Failure to warn- collapse of systems and high impact on communities True negative Winners are those practicing adjustment change or transformational change to non climate factors

37 Thankyou