Some responses of Australian researchers to drought and climate variability?

Transcription

1 Drought - Past and Future An Australian National University Water Initiative Some responses of Australian researchers to drought and climate variability? John Williams, Commissioner NSW Natural Resources Commission th November 2008 Hedley Bull Centre Australian National University

2 6 November 2002 Riverina

3 6 November 2002 Riverina.10 minutes later

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6 A well used slide by Peter Cullen

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8 The CSIRO/BOM analysis shows that extent and frequency of exceptionally hot years have been increasing over recent decades, and that trend is expected to continue. only some parts of the country will be affected climate change is not always the culprit.

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15 Rainfall trend (1910 to 2005)

16 Source: Barry Hanstrum, Bureau of Meteorology

17 Tasmania Annual Rainfall-anomaly

18 Tasmania Annual Rainfall-high rainfall years

19 Tasmania Annual Rainfall-low rainfall years

20 Annual Flows In Lachlan River at Forbes 2 December 2008 TYPE IN PRESENTATION NAME 20

21 Annual Flows in Lachlan River at Forbes

22 Annual Flows in Murrumbidgee at Wagga Wagga

23 Normal Distribution of Rainfall at Burrunjuck Climate Shifts- Implications for Water Availability Average Rainfall has increased but climate variability has also increased Source: Shahbaz Khan, CSIRO Land and Water Annual Rainfall

24 Changes in Seasonal Flows in Murrumbidgee at Balranald Source: Shahbaz Khan CSIRO Land and Water PRE 1949 POST Extraction Natural Conditions

25 3 0,0 0 0 MURRAY RIVER FLOW AT MOUTH 2 5,0 0 0 Flow (GL/year) 2 0, , ,0 0 0 N a t u r a l C o n d i t i o n s 5, D e v e l o p m e n t P e r c e n t a g e o f Y e a r s T h a t F l o w is L e s s T h a n V a l u e Source: Shahbaz Khan CSIRO Land and Water/Charles Sturt University

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27 Drought and water management land use Change distribution of land-uses to minimise impacts Hazard assessment of economic and environmental vulnerability to drought develop maps and analysis build in climate change Use medium-term weather forecasts to predict how drought risk can be minimised

28 The cycle of R&D Biophysical knowledge APSIM- Farming System models Decision support Risk assessment & evaluation New production systems Environmental remediation

29 Drought and water management - rain fed areas Risk assessment of current dryland farming driven by historical climate and climate change data Clay soil Probability Loam soil Yield (tonnes/ha)

30 Analysis of Drought at Walgett Soil water store is 190mm Soil water store is 190mm Soil water store is 100mm

31 Location: Crop: Sowing window: Soil Type: Planting Rules: N Level: Walgett wheat 1 May 31 Jul Vertosols, PAWC=240mm when 60cm depth 75% full N=75kg/ha NonReset = Continuous simulation from without resetting the soil profile Reset = Reset soil nitrogen/organic carbon every year to the same level

32 Location: Walgett Crop: wheat Sowing Dates: Fixed sowing on: 15-Apr, 15-May, 15-Jun, 15-Jul Soil Type: Vertosols, PAWC=240mm Planting Rules: Assuming profile 2/3 full with water at sowing date N Level: N=75kg/ha Weather Data: Sow date=15-apr Sow date=15-may Sow date=15-jun Sow date=15-jul 70 Probability Yield (kg/ha)

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36 Drought and water management Change in land-use distribution. Building on more detailed analysis and measurement on the above to develop for Australia a robust set of maps and analysis that sets out the change in farming and landuse that can greatly reduce the risk of drought damage.

37 Drought and water management The development of new farming and forestry systems that do not harm the environment and have capacity to buffer against drought while generating income to support communities must be an urgent goal for rural Australia.

38 Mallee 2002 Improved cropping systems can lead to increased productivity in good years and can reduce environmental damage in poor years CSIRO LAND and WATER

39 Waikerie SA: Annual Rainfall 252mm mm (Decile 1) 2002 : -Intensive Cropping with Zero Tillage -some crop (cash flow) -stable soil (this years crop and last years stubble) -ready to crop next year CSIRO LAND and WATER CSIRO LAND and WATER

40 Loxton SA: Annual Rainfall 273mm mm (Decile 1) 2002: -Excessive Cultivation -no stubble protection -crop lost this year -soil and nutrients lost -major restoration required before further production CSIRO LAND and WATER CSIRO LAND and WATER

41 Drought and water management new industries Develop new farming and forestry systems that do not harm the environment buffer against drought generate income from ecosystems service payments to support communities

42 s D CSIRO Drought r and Farming o u g h t i Drought and farming overview s a CSIRO is improving water efficiency and c developing techniques o n to help farms remain s productive during drought conditions. t a n t Drought is a constant threat for Australian t farmers. Increasing pressure on water resources h r means farmers have to be constantly aware of e a how much water their crops use and how to get t f the most out of what water is available. o r precision agriculture and spatial modelling tools developing drought tolerant plants developing new cropping practices. A u s t r a l i a n f a r

43 Drought and water management We can reduce the impact of drought in our towns and cities by water re-use, savings and re-plumbing our cities as infrastructure is being replaced in new towns and suburbs. 25% of water extracted from our rivers and groundwater is used for urban domestic and industrial use. Cities are exporters of water. Overall we only re-use about 11% of our water in urban centers

44 Drought and water management The science of how rivers and irrigation areas are linked and work as one is critical to Australia getting a water policy environment that can deal better with drought. How best to manage our rivers and groundwater systems against the tension between extraction for irrigation and urban use, and the need for environmental flows that can maintain health of rivers, groundwater, wetlands and estuaries

45 Irrigated Agriculture

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48 Tension between water extraction and water for river health CSIRO LAND and WATER

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50 Water property rights Research active in clarifing water property rights and the obligations associated with those rights to give farmers some certainty and to enable water to be recovered for the environment.

51 Climate variability Water Level Serpentine Dam Feb 2002 (20% reduction in rainfall for past 26 years)

52 Climate variability: inflow 1000 decrease Total annual inflow (GL) % reduction in Rainfall results in 25% reduction in Water Yield YEAR Inflow 1911 to 1974 (338 GL av) 1975 to 2001 (167 GL av) Note: A year is taken as May to April and labelled year is start (winter) of year Year 2001 inflows are not for a full year

53 Climate change Summer Winter Projected Rainfall Decreases Projected Rainfall Decreases Autumn Spring

54 CSIRO usually has two voices Status quo focus-productivity-survive Longer term change implication environment/social

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