Convegno Siccità

	Presidenza del Consiglio dei Ministri *Dipartimento per i Servizi Tecnici Nazionali* Commissario Governativo per l'emergenza idrica in Sardegna *Presidente della Giunta Regionale* SICCITÀ: MONITORAGGIO, MITIGAZIONE, EFFETTI Cagliari - Villasimius 21-23 Settembre 2000 Speaker: S. Power, National Climate Center, Melbourne, Australia Authors addresses: Power, Scott, (National Climate Centre, Bureau of Meteorology, Australia, GPO Box 1289K, Melbourne, 3001, AUSTRALIA), +613 9669 4085, s.power@bom.gov.au Laughlin, Greg, (Bureau of Rural Sciences, Canberra ACT, AUSTRALIA) Clark, Anthony, (Bureau of Rural Sciences, Canberra ACT, AUSTRALIA) Drought in Australia: Impacts, Mitigation, Monitoring, Policy and Prediction. Abstract: Drought has a big impact on the environment, agricultural production and the well-being of Australians - especially those in rural areas. Government policy is now more focussed on drought as a normal part of the agricultural environment, where self-reliance amongst primary producers and the sustainability of agricultural and environmental resources are amongst the main objectives. Allowance is made to provide both business and welfare support for events that are rare and severe, beyond what can be dealt with using normal risk management practices. The procedures and criteria used to assess "Exceptional Circumstances" are described. Increased self-reliance requires data on the current and future status of drought. Rainfall deficiency is monitored via an observation network from which data are increasingly being submitted and disseminated electronically. Agricultural drought is monitored using a variety of techniques including physically based models of pasture, grass and crop growth in conjunction with satellite data. Rainfall, temperature, crop and pasture outlooks are widely available to the general public through a variety of channels and are proving to be a useful source of information for farmers and others. Increased self-reliance and sustainability may result from: outlooks with greater skill and longer lead times; more wide-spread and prudent use of outlooks in management; improved monitoring of drought, agricultural and ecological conditions; further development of integrated business/financial/climate/agricultural decision support tools; more research aimed at increasing our understanding of the causes and predictability of climate variability and how this relates to both agricultural and ecological systems; and policies which focus on management skills, including drought preparedness strategies. Key words: Australian drought, ENSO, impacts, mitigation, monitoring, prediction,policy, self-reliance, sustainability, challenges ahead. 1. Introduction Australia is not only the world's smallest continent but it is, with the exception of Antarctica, also the driest. The level of variability in rainfall also tends to be larger, primarily because of the profound impact that the El NiÁo-Southern Oscillation (ENSO) phenomenon (Nicholls 1997) has in our region. This variability, particularly drought, has a marked impact on our environment, agricultural production and the income and well-being of farming families in rural Australia and so its not surprising that drought is a subject of great importance to us. In this paper we will briefly discuss: the impact that droughts have in Australia; the policies aimed at ensuring sustainable ecological systems and facilitating more wide-spread self reliance in the rural sector, and rapid recovery from drought; the systems in place to monitor and predict drought and rainfall deficiency; present mitigation strategies; and how all of the above may evolve in the future. 2. Impact of Drought in Australia Drought is, on average, Australia's most costly natural hazard (EMA 1997), primarily because it causes lost agricultural production (e.g., B. White 2000). The 1994/95 drought, for example, resulted in a 47% reduction in farm production, a US$2000 million or 0.75% drop in GDP, increased unemployment in sections of rural Australia and a 9% reduction in rural exports (ABARE 1995. See also Munro and Lembit 1997). Widespread droughts are also believed to depreciate the Australian dollar as a result of increased national debt. Droughts in Australia can have a very large spatial extent and have, at times, covered most of the continent (http://www.bom.gov.au/climate/ahead/soirain.shtml). They can also last twelve months or more. In fact part of SE Australia is currently experiencing a widespread rainfall deficiency extending back four years. Droughts can have an enormous impact on the lives of people in rural Australia, resulting in increases in divorce, suicide and illness (Munro and Lembit 1997). Within smaller communities it can accelerate the loss of population and infrastructure as small businesses, banks, retail outlets and some government offices close and people move to larger regional centres seeking employment and a wider range of services. For those remaining life becomes more difficult and more expensive (Munro and Lembit 1997). Drought also has a profound influence on the agro-ecological environment. For example, soil loss can occur if total stock numbers including farm, feral and native animals remain at pre-drought levels - especially if the drought is followed by heavy rain. The mix of vegetation can be severely effected, resulting in long-term changes,e.g. an increased abundance of weeds or loss of desirable perennial species. In northern Australia, for example, 85% of cattle production is on native pasture and 60% of this is degraded,and this is in large part due to overstocking in drought (Brook et al. 1992; McKeon and White 1992). In fact drought, market fluctuations and overstocking have been largely responsible for the degradation of 18% of Queensland range-lands to the point where it is considered uneconomic to restore them (Mott and Tothill 1992; Tothill and Gillies 1992; McKeon and White 1992). The 1982/83 drought, perhaps the most severe in the 20^th Century, cost over US$4000 million in reduced production and insurance claims.This drought resulted in a 40% drop in cereal grain, cotton and sugar production, the death of millions of livestock, tonnes of top-soil blown away in dust-storms and culminated in the horrific "Ash Wednesday" bushfires across Victoria and South Australia (EMA 1997), with the loss of many lives. 3. Drought Policy and its Evolution In the past drought was regarded as a catastrophic and unpredictable event for which little could be done to mitigate its impact. This approach emphasized the need to maintain farm income and breeding stock above certain levels and expand the total farm area (O'Meagher et al. 1998). This led to misdirected financial resources and land degradation (Smith et al. 1992; Gretton and Salma 1996). Australian farmers were traditionally granted financial relief when drought was declared in the form of rebates or subsidies on the transport of stock and fodder, low interest loans and interest rate subsidies (Monro and Lembit 1997). Unfortunately this encouraged some farmers to overstock in the early stages of drought (White and Howden 1991) causing payments to become larger and more frequent. The expectation of relief became entrenched thereby reducing the scope for self-reliance (O'Meagher et al. 1998). In the latter part of the twentieth century attitudes to drought and the management of drought began to change. It became more widely appreciated that drought is an inescapable feature of life in Australia, and questions arose as to the long-term sustainability of current farming practices and policy related to drought. Research also led to the increasing availability of tools whereby the management of drought could be improved. These factors led to the development of the National Drought Policy, established by Australia's Commonwealth and State/Territory governments in 1992. The three principles of the policy are to: (i)encourage primary producers and other sections of rural Australia to adopt self-reliant approaches to managing climatic variability; (ii)maintain and protect Australia's agricultural and environmental resource base during periods of extreme climatic stress; and (iii)ensure early recovery of agricultural and rural industries, consistent with long term sustainable levels. The core principle of self-reliance maintained that farmers and agricultural professionals were in the best position to develop the agronomic systems, practices and business strategies that would manage for the occurrence of agronomic droughts in Australia.This moved Australia's drought policy away from a subsidy-based, reactionary or "crisis-driven" approach to one in which drought is seen as a normal part of the Australian farming scene.The self-reliance policy focused rural Australia on developing risk management strategies to manage climate and market variability and to decrease the impact of drought on agricultural production. The former policies that provided direct subsidies and other forms of support to underwrite drought risk were also phased out under this policy. This policy was subsequently complemented by a policy of Drought Exceptional Circumstances (DEC), where the Commonwealth and States acknowledged that there were times in which farm businesses and rural communities would need assistance to manage drought. These were deemed to be rare and severe events: rare being a one in twenty year event, and severe being either more than twelve months or at least three consecutive failed seasons depending on the nature of the production system being considered.For a region that was deemed to be experiencing a drought event of this nature, business support was provided in the form of an interest rate subsidy, while welfare support was provided to the farm family to help with education health care costs and to provide resources for basic needs. The framework revolved around the assessment of 6 criteria: meteorological conditions; agronomic and stock conditions; water supplies; environmental impacts; farm income levels, and scale of the event. DEC would be declared when the combined impact on farmers of the six criteria was a rare and severe occurrence, and that meteorological criteria would be the threshold or primary condition.Drought support continued until it could be demonstrated that climatic and agronomic conditions had returned to a level that was considered "normal". Of course not all exceptional years of detriment to farmers are drought years - rodent and insect plagues, crop and livestock disease, frosts and water-logging can also present problems. The Government subsequently broadened the concept of DEC to Exceptional Circumstances (EC) in 1997 in recognition of this. In 1999, the criteria for assistance of these risks, including drought became: (i)the event, or events must be rare and severe; (ii)the effects of the event, or events must result in a severe downturn in farm income over a prolonged period; and, (iii)the event must not be predictable or part of a process of structural adjustment. The key indicator, a severe income downturn, should be tied to a specific rare and severe event, and be beyond normal risk management strategies employed by responsible farmers. The criteria define "rare" events as those that occur, on average, once every 20 to 25 years.The event is "severe" if it lasts for a prolonged period, or greater than twelve months, and is of a scale to affect a significant proportion of farm businesses in a region. One of the difficulties in implementing the Exceptional Circumstances policy is that compared with meteorological data there is much less reliable economic and production data available in order to make an objective assessment as to whether or not the conditions are indeed exceptional. The government also extended the period of revocation of drought assistance from 6 to 12 months and this has raised questions in some quarters as to whether or not the objectives of the National Drought Policy - self-reliance, sustainability and rapid recovery from drought, for example, will be achieved. The provision of business support during recovery from a rare drought event has also been the subject of some debate. This is especially true for interest rate subsidies as they may be obstacles to improving farm productivity (McColl 1997) and the adoption of improved risk management strategies. Communication of the current EC assessment processes is also the topic of discussion.Some stakeholders don't understand or accept the rationale or methods used in the process.Many see the objective analysis undertaken in the review process as a "black box" and do not trust the results of the scientific modelling undertaken. Those affected by decisions often question the long-term historical perspective that is taken to define rare and severe events. A move towards a more participatory drought response strategy and alternative support mechanisms to interest rate subsidies are currently being debated in the National Rural Affairs Advisory Council. Some argue that this will increase the transparency of the process and move assistance away from measures that impede productivity improvement and innovations in risk management. 4. Drought Monitoring (a) Meteorological Drought The Bureau of Meteorology monitors rainfall deficiency across Australia, and the corresponding observational network is a key asset in Australia's approach to drought.The network consists of approximately 7000 stations, the majority of which are supervised by volunteers. Most of this data is sent to the National Climate Centre in hard copy form where it is subsequently digitized and quality checked. Some of the data is also sent electronically from approximately 300 automatic weather stations and from about 1500 observers via phone lines using electronic field books and rainfall observer terminals. The data received electronically is made available in near real-time, with only minimal quality checking, though this is currently being addressed. High level quality checking of all the data received is completed after approximately 2 months and then made available to the public. The Bureau of Meteorology produces a wide range of rainfall maps which are made available via a web-site at http://www.bom.gov.au/climate/rainmaps/index.shtml. Maps provided include rainfall over the last 24 hours through to rainfall over the last 3 years, rainfall to date in the current month, and rainfall deficiency over various periods.Analyses including totals, deciles, percentage of long-term values and departures from long-term averages are provided. In addition to this free service maps of rainfall over past years dating back to 1900 are made available via the web through our cost-recovery, registered user web service called SILO (http://www.bom.gov.au/silo ). Because of the importance of ENSO to Australia, close attention is also paid to the status of the tropical Pacific. We routinely monitor the Southern Oscillation Index (SOI - which provides a measure of ENSO activity) and ocean temperatures down to 400m. Surface temperatures in the Indian Ocean to our west are also monitored as these too can influence our rainfall. The analyses of surface and sub-surface tropical Pacific Ocean temperatures (Smith 1995) are based on data from the volunteer observing XBT program (TWXXPPC 1993) and the TOGA TOA array (Hayes et al. 1991). This information is summarized in a range of booklets including the "Climate Monitoring Bulletin", which contains a summary of the global and regional climatic situation and covers mean sea-level pressure, the SOI, upper atmospheric variability, tropospheric winds, ocean temperatures, rainfall, land surface temperatures, ozone, and sea-level. This is sent to numerous individuals and agencies both in Australia and overseas. Our State offices produce monthly climate summaries providing more detailed information on a district basis, as well as information on significant weather events. A "Drought Review-Australia" booklet is also produced, which describes rainfall deficiencies across Australia. This is sent to libraries, research institutes, and other government agencies.A brief summary is issued as a press release to the mass media. The demand for the booklet is dropping as more and more people gain access to the same information via our web-site. A "Monthly Rainfall Review" is also produced and disseminated that describes rainfall generally and includes district analyses. Some of the information is then condensed and used in our "Annual Climate Summary". A small part of this information is then sent to the World Meteorological Organization and other agencies so that global summaries can be provided. (b)Agricultural Drought As touched on previously, pasture and crop production is only partially related to monthly and seasonal rainfall amounts (e.g. Hammer et al. 1993). Thus drought assessments related to agricultural production need to consider a wider range of factors. Australia is quite fortunate in that it has a number of State and federal research agencies that have put considerable work into developing crop, grassland and pasture simulation models to monitor "agricultural drought". A large number of organizations have pooled their resources and expertise to develop a National Drought Alert System called Aussie GRASS (Australian Grassland and Rangeland Assessment by Spatial Simulation, Brook and Carter 1994; Carter et al. 2000) to monitor the status of pastures and grasslands across Australia. At the heart of the system is a pasture growth model called GRASP (McKeon et al. 1982) which uses data relating to soil class, pasture type, tree cover, herbivore density,nutrient availability, and meteorological conditions. Daily meteorological data needed to run the pasture model are disseminated in near real-time via the web (http://www.bom.gov.au/silo ). The system produces estimates of pasture utilisation, gound cover changes, current pasture condition and growth, and places this in the context of the last 40 years. A range of other information such as curing indices, and risk of grass fire are also produced. Similar work using a wheat production model is also being conducted (http://www.apsru.gov.au). There are a number of other research groups that produce real time output, or provide the modelling frameworks to simulate the influence of climate variability for most of Australia's agricultural regions, e.g., the temperate production system models GRASSGRO (Donelly et al. 1998); and a wheat production system called STIN (Stephens 1998). Of course some caution needs to be adopted when applying simulation studies to decision making, to ensure that the models have been well calibrated for a given production system and regional setting, and that an independent validation has been included in the study.Without considerable work to achieve a high level of precision, many simulation studies will not have the sensitivity to depict the difference between a 1 in 10-15 and a 1 in 20-25 year event. Individual farmers are assisted with their own monitoring by the recent development of various decision support tools like Graz Plan (which takes account of stocking rates, soil moisture and pasture availability for lamb producing areas of southern Australia), GrazeOn (for grazing decisions), DroughtPlan, Rainman, and Feedman. Data from satellite are also used to estimate when grasslands and crops have "dried off" as well as the spatial extent and severity of drought (McVicar and Jupp 1998a). Generally, two standard sources of data are used: reflectance data from the NOAA Advanced Very High Resolution Radiometer (AVHRR) and LANDSATThematic Mapper (TM) data. For assessment of the impact of drought on vegetation in a particular region, the Normalised Difference Vegetation Index (NDVI) is one of the common approaches. Generally, NDVI is a linear index relating the amount of red and near-infra red light reflected back to a remote sensor, and there are well-known relationships between NDVI and other measures of plant condition, such as the Leaf Area Index (LAI).Some good examples of this approach are produced by the Environment and Resources Information Network (ERIN), part of environment Australia (http://www.environment.gov.au/psg/erin/satellite ). 5. Prediction* There have been considerable improvements in our understanding of the large-scale climatic systems that influence climate variability in Australia.One of the more significant developments over the last 30 years has been an increase in our understanding of ENSO and how it effects our rainfall. This has, in part, led to an improved ability to predict the onset of drought and improve the level of drought awareness in the community. Each month the National Climate Centre issues a Seasonal Climate Outlook providing probabilities of rainfall throughout the country for the coming three months (http://www.bom.gov.au/climate/ahead ). These outlooks, together with estimates of their reliability, are useful to a wide-range of users. The operational scheme employeduses the lagged relationship between sea-surface temperature (SST) and Australian rainfall (Drosdowsky and Chambers 1998) to provide estimates of the probability of total rainfall in the following season being above various thresholds. The scheme uses Indian Ocean and Pacific Ocean SST patterns and displays greater skill than our previous operational scheme based on the SOI. The Bureau also provide longer term outlooks of tropical Pacific SST using an intermediate coupled model of the tropical Pacific (Kleeman 1993, http://www.bom.gov.au/bmrc/mrlr/rzk/climfcn3.htm). More comprehensive outlooks are provided by a global Coupled General Circulation Model of the eaAustralias atmosphere/ocean/sea-ice/land system (Power et al. 1998; Wang et al. 1999, http://www.bom.gov.au/bmrc/mrlr/fzt/CM/page1.html). This is an experimental system and only a small subset of the results are disseminated. Work is currently being conducted to assess the skill of the forecasts from this model and to use the forecasts to provide information on rainfall for the longer term (3-12 months). The National Climate Centre issues a media release summarizing all the available information in the Seasonal Climate Outlook for rainfall and temperature and this is disseminated through the mass media and via the web (http://www.bom.gov.au/climate). The Bureau also provide outlooks through regular appearances on radio and satellite TV. More detailed information is made available to our registered paying users through both mail-out and web-based services (http://www.bom.gov.au/silo). Conveying accurate but easily understood probabilistic information, particularly through the mass media is a great challenge. The simplicity and transparency of an alternative prediction system based on previous values of the SOI made it suitable for inclusion into a decision support tool called Rainman (Clewett et al. 1994) which is available to farmers, extension officers and others on a CD on a partial cost-recover basis. The system is also very useful as an extension and educational tool.Seehttp://.dnr.qld.gov.au/longpdk. Some of the agricultural models described in the previous section are also used to provide outlooks for conditions by making use of analog techniques. Outlooks for grasslands, pastures and wheat are widely distributed by post and are becoming increasingly important in decision-making ( e.g., http://www.dnr.qld.gov.au/longpdk/agrass/index.html, http://www.apsru.gov.au ). Government funding through various agencies as well as via channels specifically targetted to enhancing the widespread and prudent use of improved climate predictions(e.g., http://www.cvap.gov.au/climag1.htm, http://www.acslink.aone.net.au/asit/compend98.htm ) continues to enhance Australia's capacity to forecast conditions in the seasons ahead. Unfortunately the skill of the forecasts is not great enough to be of use in all decision making related to future climatic conditions though skill has improved and is continuing to do so on the 3-12 month period due to advances made in modelling the climate system. Education, marketing and promotion are also important strategies by which existing services and capabilities become better known and by which the needs of the community are fed back to researchers and service providers (e.g. seehttp://www.bom.gov.au/climate/cli2000/cli2000.html for an example of one way in which communication is being enhanced). 6. Mitigation While agricultural production in Australia is largely unsubsidized in Australia, policy over the past 20 years has allowed some funds to be provided to mitigate the impact of drought on the rural sector. For example, the federal government set aside an average of only US$35M per year from 1978-1996 (Munro and Lembit, 1997) for expenditure related to drought. While this was augmented by state government expenditure (approx US$110M in total spent over the period 1991-92 to January 1996) it remains a relatively modest amount. (Of course totals fluctuated from year-to-year, often in association with ENSO activity, e.g., the 5 largest pay-outs during 1978-1996 all occurred immediately after years with a negative SOI). There are numerous examples of where the effects of drought can be mitigated by individual farmers (e.g. B. White 2000). There is also a growing list of examples where seasonal forecasts have been able to assist individual farmers, especially when the forecasts have been factored in to a more general farm management strategy (e.g. White and Howden 1991). It is generally recognised that climate-forecasting information has been widely adopted when compared to other innovations in agriculture. Similarly, there is general acceptance that strategic use of forecasts can improve business stability and the environmental performance of the farm. It is important to note that mitigation strategies need not be confined to individual farms - strategies can extend up to the national scale. For example, we know that drought subsequently leads to a reduction in the growth of the national economy. This information can therefore be used to help set official lending rates by our central bank (the "Reserve Bank") to provide better outcomes for the Australian economy as a whole. 5. Summary and Discussion Australia's rainfall is, generally speaking, relatively modest but highly variable. The relatively high variability can be attributed to the influence of the El NiÁo-Southern Oscillation phenomenon and this has a big impact on agricultural production, the environment generally and the well-being of Australians, especially those in rural areas. Australian government policy has focussed on drought as a normal part of the agricultural environment, where self-reliance and sustainability are the main objectives. There is, however, allowance made to provide both business and welfare support for events that are rare and severe, beyond what can be dealt with using normal risk management practices. While the principles of self-reliance and sustainability are becoming increasingly accepted there is some debate as to whether or not the current policies are optimally tuned to reaching these objectives, particularly in the use of interest rate subsidies as a mechanism for providing assistance(e.g. McColl 1997; see also http://www.cvap.gov.au/newfsStafford.htm).Delivering sustainability can also be difficult because it can be hard to assess whether or not a specific management practice will be sustainable due to the complexity of the economic, biophysical and social systems in agriculture (Munro and Lembit 1997). Future support could focus on mechanisms that target management skills in rural Australia. The climate observation network will continue to be an important component of the implementation of national policies, whether they be drought support mechanisms, or the long term goal of providing information to improve risk management. Rainfall deficiency is monitored in near real-time using electronically submitted data from numerous sites across the country. Agricultural drought is monitored using a variety of techniques including physically based models of pasture, grass and crop growth in conjunction with satellite data. Australian agencies provide climate outlooks and these are widely available to the general public. These, together with rural enterprise forecasts, have been a useful source of information for producers seeking to secure income stability in their business, and improve the environmental performance of their farm. The probabilistic nature of the outlooks, however, can make them difficult to understand and it is not always easy for people to factor these outlooks into their decision-making strategies for a variety of reasons. There is, nevertheless, a growing number of examples where the outlooks have been used to advantage by the rural industry. There is also scope to apply the information at the national level e.g. in decisions relating to monetary policy. Increased self-reliance will continue to require innovation and reliable information through climate research and development, and future areas of focus in Australia could be: outlooks with greater skill and longer lead times; greater use of climate forecasts in management; improved monitoring of drought, agricultural and ecological conditions; further development of integrated decision support tools; more research aimed at increasing our understanding of the causes and predicability of climate variability and how this relates to both agricultural and ecological systems; and policies which focus on management skills, including drought preparedness strategies. 6. Final Comment Scenarios of future climate in a warming world taken from a range of physically-based computer models of the earth's climate suggest that Australia's rainfall may be reduced further (e.g., http://www.cru.uea.ac.uk/~mikeh/research/australia.pdf ). While there can be agricultural advantages in milder nights and increased atmospheric carbon-dioxide levels, this drying may represent a major challenge to future farmers, governments and policy-makers alike. Satisfactorily dealing with these changes, if they eventuate, will require increased effort on the various fronts described in this paper. Acknowledgements/Disclaimer Scott Power wishes to thank Barry White, David White, Greg McKeon, Grant Beard, Mary Voice and Neil Plummer for helpful discussions, and Wayne Hall for comments on an earlier draft. 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Dipartimento per i Servizi Tecnici Nazionali

Commissario Governativo per l'emergenza idrica in Sardegna
Presidente della Giunta Regionale

Abstract: Drought has a big impact on the environment, agricultural production and the well-being of Australians - especially those in rural areas. Government policy is now more focussed on drought as a normal part of the agricultural environment, where self-reliance amongst primary producers and the sustainability of agricultural and environmental resources are amongst the main objectives. Allowance is made to provide both business and welfare support for events that are rare and severe, beyond what can be dealt with using normal risk management practices. The procedures and criteria used to assess "Exceptional Circumstances" are described.

Increased self-reliance requires data on the current and future status of drought. Rainfall deficiency is monitored via an observation network from which data are increasingly being submitted and disseminated electronically. Agricultural drought is monitored using a variety of techniques including physically based models of pasture, grass and crop growth in conjunction with satellite data. Rainfall, temperature, crop and pasture outlooks are widely available to the general public through a variety of channels and are proving to be a useful source of information for farmers and others.

further development of integrated business/financial/climate/agricultural decision support tools;

more research aimed at increasing our understanding of the causes and predictability of climate variability and how this relates to both agricultural and ecological systems;

and policies which focus on management skills, including drought preparedness strategies.

Key words: Australian drought, ENSO, impacts, mitigation, monitoring, prediction,policy, self-reliance, sustainability, challenges ahead.

Australia is not only the world's smallest continent but it is, with the exception of Antarctica, also the driest. The level of variability in rainfall also tends to be larger, primarily because of the profound impact that the El NiÁo-Southern Oscillation (ENSO) phenomenon (Nicholls 1997) has in our region. This variability, particularly drought, has a marked impact on our environment, agricultural production and the income and well-being of farming families in rural Australia and so its not surprising that drought is a subject of great importance to us.

*the policies aimed at ensuring sustainable ecological systems and facilitating more wide-spread self reliance in the rural sector, and rapid recovery from drought;

2. Impact of Drought in Australia

Drought is, on average, Australia's most costly natural hazard (EMA 1997), primarily because it causes lost agricultural production (e.g., B. White 2000). The 1994/95 drought, for example, resulted in a 47% reduction in farm production, a US$2000 million or 0.75% drop in GDP, increased unemployment in sections of rural Australia and a 9% reduction in rural exports (ABARE 1995. See also Munro and Lembit 1997). Widespread droughts are also believed to depreciate the Australian dollar as a result of increased national debt.

Droughts in Australia can have a very large spatial extent and have, at times, covered most of the continent (http://www.bom.gov.au/climate/ahead/soirain.shtml). They can also last twelve months or more. In fact part of SE Australia is currently experiencing a widespread rainfall deficiency extending back four years.

Droughts can have an enormous impact on the lives of people in rural Australia, resulting in increases in divorce, suicide and illness (Munro and Lembit 1997). Within smaller communities it can accelerate the loss of population and infrastructure as small businesses, banks, retail outlets and some government offices close and people move to larger regional centres seeking employment and a wider range of services. For those remaining life becomes more difficult and more expensive (Munro and Lembit 1997).

Drought also has a profound influence on the agro-ecological environment. For example, soil loss can occur if total stock numbers including farm, feral and native animals remain at pre-drought levels - especially if the drought is followed by heavy rain. The mix of vegetation can be severely effected, resulting in long-term changes,e.g. an increased abundance of weeds or loss of desirable perennial species. In northern Australia, for example, 85% of cattle production is on native pasture and 60% of this is degraded,and this is in large part due to overstocking in drought (Brook et al. 1992; McKeon and White 1992). In fact drought, market fluctuations and overstocking have been largely responsible for the degradation of 18% of Queensland range-lands to the point where it is considered uneconomic to restore them (Mott and Tothill 1992; Tothill and Gillies 1992; McKeon and White 1992).

The 1982/83 drought, perhaps the most severe in the 20^th Century, cost over US$4000 million in reduced production and insurance claims.This drought resulted in a 40% drop in cereal grain, cotton and sugar production, the death of millions of livestock, tonnes of top-soil blown away in dust-storms and culminated in the horrific "Ash Wednesday" bushfires across Victoria and South Australia (EMA 1997), with the loss of many lives.

3. Drought Policy and its Evolution

In the past drought was regarded as a catastrophic and unpredictable event for which little could be done to mitigate its impact. This approach emphasized the need to maintain farm income and breeding stock above certain levels and expand the total farm area (O'Meagher et al. 1998). This led to misdirected financial resources and land degradation (Smith et al. 1992; Gretton and Salma 1996). Australian farmers were traditionally granted financial relief when drought was declared in the form of rebates or subsidies on the transport of stock and fodder, low interest loans and interest rate subsidies (Monro and Lembit 1997). Unfortunately this encouraged some farmers to overstock in the early stages of drought (White and Howden 1991) causing payments to become larger and more frequent. The expectation of relief became entrenched thereby reducing the scope for self-reliance (O'Meagher et al. 1998).

In the latter part of the twentieth century attitudes to drought and the management of drought began to change. It became more widely appreciated that drought is an inescapable feature of life in Australia, and questions arose as to the long-term sustainability of current farming practices and policy related to drought. Research also led to the increasing availability of tools whereby the management of drought could be improved.

These factors led to the development of the National Drought Policy, established by Australia's Commonwealth and State/Territory governments in 1992. The three principles of the policy are to:

(ii)maintain and protect Australia's agricultural and environmental resource base during periods of extreme climatic stress; and

(iii)ensure early recovery of agricultural and rural industries, consistent with long term sustainable levels.

The core principle of self-reliance maintained that farmers and agricultural professionals were in the best position to develop the agronomic systems, practices and business strategies that would manage for the occurrence of agronomic droughts in Australia.This moved Australia's drought policy away from a subsidy-based, reactionary or "crisis-driven" approach to one in which drought is seen as a normal part of the Australian farming scene.The self-reliance policy focused rural Australia on developing risk management strategies to manage climate and market variability and to decrease the impact of drought on agricultural production. The former policies that provided direct subsidies and other forms of support to underwrite drought risk were also phased out under this policy.

This policy was subsequently complemented by a policy of Drought Exceptional Circumstances (DEC), where the Commonwealth and States acknowledged that there were times in which farm businesses and rural communities would need assistance to manage drought. These were deemed to be rare and severe events: rare being a one in twenty year event, and severe being either more than twelve months or at least three consecutive failed seasons depending on the nature of the production system being considered.For a region that was deemed to be experiencing a drought event of this nature, business support was provided in the form of an interest rate subsidy, while welfare support was provided to the farm family to help with education health care costs and to provide resources for basic needs.

The framework revolved around the assessment of 6 criteria: meteorological conditions; agronomic and stock conditions; water supplies; environmental impacts; farm income levels, and scale of the event. DEC would be declared when the combined impact on farmers of the six criteria was a rare and severe occurrence, and that meteorological criteria would be the threshold or primary condition.Drought support continued until it could be demonstrated that climatic and agronomic conditions had returned to a level that was considered "normal".

Of course not all exceptional years of detriment to farmers are drought years - rodent and insect plagues, crop and livestock disease, frosts and water-logging can also present problems. The Government subsequently broadened the concept of DEC to Exceptional Circumstances (EC) in 1997 in recognition of this. In 1999, the criteria for assistance of these risks, including drought became:

(ii)the effects of the event, or events must result in a severe downturn in farm income over a prolonged period; and,

(iii)the event must not be predictable or part of a process of structural adjustment.

The key indicator, a severe income downturn, should be tied to a specific rare and severe event, and be beyond normal risk management strategies employed by responsible farmers. The criteria define "rare" events as those that occur, on average, once every 20 to 25 years.The event is "severe" if it lasts for a prolonged period, or greater than twelve months, and is of a scale to affect a significant proportion of farm businesses in a region.

One of the difficulties in implementing the Exceptional Circumstances policy is that compared with meteorological data there is much less reliable economic and production data available in order to make an objective assessment as to whether or not the conditions are indeed exceptional. The government also extended the period of revocation of drought assistance from 6 to 12 months and this has raised questions in some quarters as to whether or not the objectives of the National Drought Policy - self-reliance, sustainability and rapid recovery from drought, for example, will be achieved.

The provision of business support during recovery from a rare drought event has also been the subject of some debate. This is especially true for interest rate subsidies as they may be obstacles to improving farm productivity (McColl 1997) and the adoption of improved risk management strategies.

Communication of the current EC assessment processes is also the topic of discussion.Some stakeholders don't understand or accept the rationale or methods used in the process.Many see the objective analysis undertaken in the review process as a "black box" and do not trust the results of the scientific modelling undertaken. Those affected by decisions often question the long-term historical perspective that is taken to define rare and severe events. A move towards a more participatory drought response strategy and alternative support mechanisms to interest rate subsidies are currently being debated in the National Rural Affairs Advisory Council. Some argue that this will increase the transparency of the process and move assistance away from measures that impede productivity improvement and innovations in risk management.

4. Drought Monitoring

The Bureau of Meteorology monitors rainfall deficiency across Australia, and the corresponding observational network is a key asset in Australia's approach to drought.The network consists of approximately 7000 stations, the majority of which are supervised by volunteers. Most of this data is sent to the National Climate Centre in hard copy form where it is subsequently digitized and quality checked. Some of the data is also sent electronically from approximately 300 automatic weather stations and from about 1500 observers via phone lines using electronic field books and rainfall observer terminals. The data received electronically is made available in near real-time, with only minimal quality checking, though this is currently being addressed. High level quality checking of all the data received is completed after approximately 2 months and then made available to the public.

The Bureau of Meteorology produces a wide range of rainfall maps which are made available via a web-site at http://www.bom.gov.au/climate/rainmaps/index.shtml. Maps provided include rainfall over the last 24 hours through to rainfall over the last 3 years, rainfall to date in the current month, and rainfall deficiency over various periods.Analyses including totals, deciles, percentage of long-term values and departures from long-term averages are provided. In addition to this free service maps of rainfall over past years dating back to 1900 are made available via the web through our cost-recovery, registered user web service called SILO (http://www.bom.gov.au/silo ).

Because of the importance of ENSO to Australia, close attention is also paid to the status of the tropical Pacific. We routinely monitor the Southern Oscillation Index (SOI - which provides a measure of ENSO activity) and ocean temperatures down to 400m. Surface temperatures in the Indian Ocean to our west are also monitored as these too can influence our rainfall. The analyses of surface and sub-surface tropical Pacific Ocean temperatures (Smith 1995) are based on data from the volunteer observing XBT program (TWXXPPC 1993) and the TOGA TOA array (Hayes et al. 1991).

This information is summarized in a range of booklets including the "Climate Monitoring Bulletin", which contains a summary of the global and regional climatic situation and covers mean sea-level pressure, the SOI, upper atmospheric variability, tropospheric winds, ocean temperatures, rainfall, land surface temperatures, ozone, and sea-level. This is sent to numerous individuals and agencies both in Australia and overseas. Our State offices produce monthly climate summaries providing more detailed information on a district basis, as well as information on significant weather events. A "Drought Review-Australia" booklet is also produced, which describes rainfall deficiencies across Australia. This is sent to libraries, research institutes, and other government agencies.A brief summary is issued as a press release to the mass media. The demand for the booklet is dropping as more and more people gain access to the same information via our web-site. A "Monthly Rainfall Review" is also produced and disseminated that describes rainfall generally and includes district analyses.

Some of the information is then condensed and used in our "Annual Climate Summary". A small part of this information is then sent to the World Meteorological Organization and other agencies so that global summaries can be provided.

As touched on previously, pasture and crop production is only partially related to monthly and seasonal rainfall amounts (e.g. Hammer et al. 1993). Thus drought assessments related to agricultural production need to consider a wider range of factors. Australia is quite fortunate in that it has a number of State and federal research agencies that have put considerable work into developing crop, grassland and pasture simulation models to monitor "agricultural drought". A large number of organizations have pooled their resources and expertise to develop a National Drought Alert System called Aussie GRASS (Australian Grassland and Rangeland Assessment by Spatial Simulation, Brook and Carter 1994; Carter et al. 2000) to monitor the status of pastures and grasslands across Australia. At the heart of the system is a pasture growth model called GRASP (McKeon et al. 1982) which uses data relating to soil class, pasture type, tree cover, herbivore density,nutrient availability, and meteorological conditions. Daily meteorological data needed to run the pasture model are disseminated in near real-time via the web (http://www.bom.gov.au/silo ). The system produces estimates of pasture utilisation, gound cover changes, current pasture condition and growth, and places this in the context of the last 40 years. A range of other information such as curing indices, and risk of grass fire are also produced. Similar work using a wheat production model is also being conducted (http://www.apsru.gov.au).

There are a number of other research groups that produce real time output, or provide the modelling frameworks to simulate the influence of climate variability for most of Australia's agricultural regions, e.g., the temperate production system models GRASSGRO (Donelly et al. 1998); and a wheat production system called STIN (Stephens 1998). Of course some caution needs to be adopted when applying simulation studies to decision making, to ensure that the models have been well calibrated for a given production system and regional setting, and that an independent validation has been included in the study.Without considerable work to achieve a high level of precision, many simulation studies will not have the sensitivity to depict the difference between a 1 in 10-15 and a 1 in 20-25 year event.

Individual farmers are assisted with their own monitoring by the recent development of various decision support tools like Graz Plan (which takes account of stocking rates, soil moisture and pasture availability for lamb producing areas of southern Australia), GrazeOn (for grazing decisions), DroughtPlan, Rainman, and Feedman.

Data from satellite are also used to estimate when grasslands and crops have "dried off" as well as the spatial extent and severity of drought (McVicar and Jupp 1998a). Generally, two standard sources of data are used: reflectance data from the NOAA Advanced Very High Resolution Radiometer (AVHRR) and LANDSATThematic Mapper (TM) data.

For assessment of the impact of drought on vegetation in a particular region, the Normalised Difference Vegetation Index (NDVI) is one of the common approaches. Generally, NDVI is a linear index relating the amount of red and near-infra red light reflected back to a remote sensor, and there are well-known relationships between NDVI and other measures of plant condition, such as the Leaf Area Index (LAI).Some good examples of this approach are produced by the Environment and Resources Information Network (ERIN), part of environment Australia (http://www.environment.gov.au/psg/erin/satellite ).

5. Prediction

There have been considerable improvements in our understanding of the large-scale climatic systems that influence climate variability in Australia.One of the more significant developments over the last 30 years has been an increase in our understanding of ENSO and how it effects our rainfall. This has, in part, led to an improved ability to predict the onset of drought and improve the level of drought awareness in the community.

Each month the National Climate Centre issues a Seasonal Climate Outlook providing probabilities of rainfall throughout the country for the coming three months (http://www.bom.gov.au/climate/ahead ). These outlooks, together with estimates of their reliability, are useful to a wide-range of users. The operational scheme employeduses the lagged relationship between sea-surface temperature (SST) and Australian rainfall (Drosdowsky and Chambers 1998) to provide estimates of the probability of total rainfall in the following season being above various thresholds. The scheme uses Indian Ocean and Pacific Ocean SST patterns and displays greater skill than our previous operational scheme based on the SOI.

The Bureau also provide longer term outlooks of tropical Pacific SST using an intermediate coupled model of the tropical Pacific (Kleeman 1993, http://www.bom.gov.au/bmrc/mrlr/rzk/climfcn3.htm). More comprehensive outlooks are provided by a global Coupled General Circulation Model of the eaAustralias atmosphere/ocean/sea-ice/land system (Power et al. 1998; Wang et al. 1999, http://www.bom.gov.au/bmrc/mrlr/fzt/CM/page1.html). This is an experimental system and only a small subset of the results are disseminated. Work is currently being conducted to assess the skill of the forecasts from this model and to use the forecasts to provide information on rainfall for the longer term (3-12 months).

The National Climate Centre issues a media release summarizing all the available information in the Seasonal Climate Outlook for rainfall and temperature and this is disseminated through the mass media and via the web (http://www.bom.gov.au/climate). The Bureau also provide outlooks through regular appearances on radio and satellite TV. More detailed information is made available to our registered paying users through both mail-out and web-based services (http://www.bom.gov.au/silo). Conveying accurate but easily understood probabilistic information, particularly through the mass media is a great challenge.

The simplicity and transparency of an alternative prediction system based on previous values of the SOI made it suitable for inclusion into a decision support tool called Rainman (Clewett et al. 1994) which is available to farmers, extension officers and others on a CD on a partial cost-recover basis. The system is also very useful as an extension and educational tool.Seehttp://.dnr.qld.gov.au/longpdk.

Some of the agricultural models described in the previous section are also used to provide outlooks for conditions by making use of analog techniques. Outlooks for grasslands, pastures and wheat are widely distributed by post and are becoming increasingly important in decision-making ( e.g., http://www.dnr.qld.gov.au/longpdk/agrass/index.html, http://www.apsru.gov.au ).

Government funding through various agencies as well as via channels specifically targetted to enhancing the widespread and prudent use of improved climate predictions(e.g., http://www.cvap.gov.au/climag1.htm, http://www.acslink.aone.net.au/asit/compend98.htm ) continues to enhance Australia's capacity to forecast conditions in the seasons ahead.

Unfortunately the skill of the forecasts is not great enough to be of use in all decision making related to future climatic conditions though skill has improved and is continuing to do so on the 3-12 month period due to advances made in modelling the climate system. Education, marketing and promotion are also important strategies by which existing services and capabilities become better known and by which the needs of the community are fed back to researchers and service providers (e.g. seehttp://www.bom.gov.au/climate/cli2000/cli2000.html for an example of one way in which communication is being enhanced).

While agricultural production in Australia is largely unsubsidized in Australia, policy over the past 20 years has allowed some funds to be provided to mitigate the impact of drought on the rural sector. For example, the federal government set aside an average of only US$35M per year from 1978-1996 (Munro and Lembit, 1997) for expenditure related to drought. While this was augmented by state government expenditure (approx US$110M in total spent over the period 1991-92 to January 1996) it remains a relatively modest amount. (Of course totals fluctuated from year-to-year, often in association with ENSO activity, e.g., the 5 largest pay-outs during 1978-1996 all occurred immediately after years with a negative SOI).

There are numerous examples of where the effects of drought can be mitigated by individual farmers (e.g. B. White 2000). There is also a growing list of examples where seasonal forecasts have been able to assist individual farmers, especially when the forecasts have been factored in to a more general farm management strategy (e.g. White and Howden 1991). It is generally recognised that climate-forecasting information has been widely adopted when compared to other innovations in agriculture. Similarly, there is general acceptance that strategic use of forecasts can improve business stability and the environmental performance of the farm.

It is important to note that mitigation strategies need not be confined to individual farms - strategies can extend up to the national scale. For example, we know that drought subsequently leads to a reduction in the growth of the national economy. This information can therefore be used to help set official lending rates by our central bank (the "Reserve Bank") to provide better outcomes for the Australian economy as a whole.

5. Summary and Discussion

Australia's rainfall is, generally speaking, relatively modest but highly variable. The relatively high variability can be attributed to the influence of the El NiÁo-Southern Oscillation phenomenon and this has a big impact on agricultural production, the environment generally and the well-being of Australians, especially those in rural areas.

Australian government policy has focussed on drought as a normal part of the agricultural environment, where self-reliance and sustainability are the main objectives. There is, however, allowance made to provide both business and welfare support for events that are rare and severe, beyond what can be dealt with using normal risk management practices.

While the principles of self-reliance and sustainability are becoming increasingly accepted there is some debate as to whether or not the current policies are optimally tuned to reaching these objectives, particularly in the use of interest rate subsidies as a mechanism for providing assistance(e.g. McColl 1997; see also http://www.cvap.gov.au/newfsStafford.htm).Delivering sustainability can also be difficult because it can be hard to assess whether or not a specific management practice will be sustainable due to the complexity of the economic, biophysical and social systems in agriculture (Munro and Lembit 1997). Future support could focus on mechanisms that target management skills in rural Australia.

The climate observation network will continue to be an important component of the implementation of national policies, whether they be drought support mechanisms, or the long term goal of providing information to improve risk management. Rainfall deficiency is monitored in near real-time using electronically submitted data from numerous sites across the country. Agricultural drought is monitored using a variety of techniques including physically based models of pasture, grass and crop growth in conjunction with satellite data.

Australian agencies provide climate outlooks and these are widely available to the general public. These, together with rural enterprise forecasts, have been a useful source of information for producers seeking to secure income stability in their business, and improve the environmental performance of their farm.

The probabilistic nature of the outlooks, however, can make them difficult to understand and it is not always easy for people to factor these outlooks into their decision-making strategies for a variety of reasons. There is, nevertheless, a growing number of examples where the outlooks have been used to advantage by the rural industry. There is also scope to apply the information at the national level e.g. in decisions relating to monetary policy.

Increased self-reliance will continue to require innovation and reliable information through climate research and development, and future areas of focus in Australia could be:

more research aimed at increasing our understanding of the causes and predicability of climate variability and how this relates to both agricultural and ecological systems;

and policies which focus on management skills, including drought preparedness strategies.

6. Final Comment

Scenarios of future climate in a warming world taken from a range of physically-based computer models of the earth's climate suggest that Australia's rainfall may be reduced further (e.g., http://www.cru.uea.ac.uk/~mikeh/research/australia.pdf ). While there can be agricultural advantages in milder nights and increased atmospheric carbon-dioxide levels, this drying may represent a major challenge to future farmers, governments and policy-makers alike. Satisfactorily dealing with these changes, if they eventuate, will require increased effort on the various fronts described in this paper.

Acknowledgements/Disclaimer

Scott Power wishes to thank Barry White, David White, Greg McKeon, Grant Beard, Mary Voice and Neil Plummer for helpful discussions, and Wayne Hall for comments on an earlier draft. Pease note that this abstract represents the views of the authors and do not necessarily represent the official views of their respective organizations or of the Australian Government.

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