An overview of climate change adaptation in Australian primary industries – impacts, options and priorities

• The recent Intergovernmental Panel on Climate Change Fourth Assessment Report concluded that the agriculture sector in Australia is particularly vulnerable to climate changes, with potential negative impacts on the amount of produce, quality of produce, reliability of production and on the natural resource base on which agriculture depends. This vulnerability requires high levels of adaptive responses. • The benefits and positive opportunities presented by climate change may start to peak during the initial stages (possibly mid century), but the negative impacts may lag behind, becoming progressively stronger over time and with greater build up of greenhouse gases in the atmosphere. Caution is therefore needed not to underestimate the long-term challenge of climate change based on initial, more moderate experiences. • This review has identified a number of potential options for Australian agriculture to adapt to climate change. Many of these options are extensions or enhancements of existing activities that are aimed at managing the impacts of existing climate variability and improving the sustainability and efficiency in the use of natural resources

Climate Change in Queensland's Grazing Lands. I. Approaches and Climatic Trends

Climate change is an important global issue but is yet to be recognised as such by many rangelands users. This paper reviews some of the uncertainties relating to pre-instrumental and future climate change and documents current trends and fluctuations in climate of Queensland's grazing lands. Analysis of daily climate surfaces for Queensland's pastoral/cropping zone shows high variability in annual rainfall which is influenced by the El NiHo-Southern Oscillation (ENSO) phenomenon. This relationship, when examined using moving windows, has changed during this century with the 1930-40s being a period of low correlation. Minimum temperatures taken from the climate surfaces also changed, showing a significant (P<0.01) increase over time especially in May. Over the 40 years since 1957, annual minimum temperatures have increased by l.0°C for the pastoral/cropping zone and coastal sub-zone, winter minimum temperatures by 1.2°C for the pastoral/cropping zone (1.3°C for the coastal sub-zone), summer minimum temperatures by 0.7°C for the pastoral/cropping zone and coastal sub-zone, and May minimum temperatures by 2.8°C for the pastoral/cropping zone (3.0°C for the coastal sub-zone). Consistent significant trends in vapour pressure (increasing, P<0.001) and solar radiation (decreasing, P<0.05) also occurred in May. The mechanisms for the identified climate trends and unusual behaviour of ENS0 are the subject of speculation with attribution of causes to natural variability or the enhanced greenhouse effect being unresolved. Continued monitoring of these trends and fluctuations will be important for the future management of Queensland's grazing lands with this analysis highlighting the need for discrimination of trends from natural variability. In terms of grazing management and degradation processes, this work also highlights that general changes in climate averages may disguise important variation at yearly and decadal time scales

CAN CLIMATE KNOWLEDGE LEAD TO BETTER RURAL POLICIES AND RISK MANAGEMENT PRACTICES?

In many parts of the world, climate is one of the biggest risk factors impacting on agricultural systems performance and management. Climate variability (CV) and climate change (CC) contributes to the vulnerability of individuals, businesses, communities and regions. Extreme climate events such as severe droughts, floods, cyclones or temperature shocks often strongly impede sustainable agricultural development. Targeted and appropriately conceptualised climate knowledge (including seasonal climate forecasting and scenario analyses) can increase overall preparedness and lead to better social, economic and environmental outcomes. Climate variability occurs over a wide range of temporal scales. Our increasing understanding of the underlaying mechanisms means that some of that variability is now predictable. Research efforts are directed towards investigating phenomena such as the Madden-Julian Oscillation (MJO; 30-60 days), ENSO related variability (2.5 - 8 years), decadal and multidecadal climate variability and climate change

Climate Change in Queensland's Grazing Lands: II. An Assessment of the Impact on Animal Production From Native Pastures

The 160 million ha of grazing land in Queensland support approximately 10 million beef equivalents (9.8 million cattle and 10.7 million sheep) with treed and cleared native pastures as the major forage source. The complexity of these biophysical systems and their interaction with pasture and stock management, economic and social forces limits our ability to easily calculate the impact of climate change scenarios. We report the application of a systems approach in simulating the flow of plant dry matter and utilisation of forage by animals. Our review of available models highlighted the lack of suitable mechanistic models and the potential role of simple empirical relationships of utilisation and animal production derived from climatic and soil indices. Plausible climate change scenarios were evaluated by using a factorial of rainfall (f 10%) * 3260C temperature increase * doubling CO, in sensitivity studies at property, regional and State scales. Simulation of beef cattle liveweight gain at three locations in the Queensland black speargrass zone showed that a *lo% change in rainfall was magnified to be a f 15% change in animal production (liveweight gain per ha) depending on location, temperature and CO, change. Models of 'safe' carrying capacity were developed from property data and expert opinion. Climate change impacts on 'safe' carrying capacity varied considerably across the State depending on whether moisture, temperature or nutrients were the limiting factors. Without the effect of doubling CO,, warmer temperatures and +lo% changes in rainfall resulted in -35 to +70% changes in 'safe' carrying capacity depending on location. With the effect of doubling CO, included, the changes in 'safe' carrying capacity ranged from -12 to +115% across scenarios and locations. When aggregated to a whole-of-State carrying capacity, the combined effects of warmer temperature, doubling CO, and +lo% changes in rainfall resulted in 'safe' carrying capacity changes of +3 to +45% depending on rainfall scenario and location. A major finding of the sensitivity study was the potential importance of doubling CO, in mitigating or amplifying the effects of warmer temperatures and changes in rainfall. Field studies on the impact of CO, are therefore a high research priority. Keywords: climate change, Queensland, simulation, rangelands, beef production, cattle, carrying capacity, CO,, utilisatio

Adapting agriculture to climate change

The strong trends in climate change already evident, the likelihood of further changes occurring, and the increasing scale of potential climate impacts give urgency to addressing agricultural adaptation more coherently. There are many potential adaptation options available for marginal change of existing agricultural systems, often variations of existing climate risk management. We show that implementation of these options is likely to have substantial benefits under moderate climate change for some cropping systems. However, there are limits to their effectiveness under more severe climate changes. Hence, more systemic changes in resource allocation need to be considered, such as targeted diversification of production systems and livelihoods. We argue that achieving increased adaptation action will necessitate integration of climate change-related issues with other risk factors, such as climate variability and market risk, and with other policy domains, such as sustainable development. Dealing with the many barriers to effective adaptation will require a comprehensive and dynamic policy approach covering a range of scales and issues, for example, from the understanding by farmers of change in risk profiles to the establishment of efficient markets that facilitate response strategies. Science, too, has to adapt. Multidisciplinary problems require multidisciplinary solutions, i.e., a focus on integrated rather than disciplinary science and a strengthening of the interface with decision makers. A crucial component of this approach is the implementation of adaptation assessment frameworks that are relevant, robust, and easily operated by all stakeholders, practitioners, policymakers, and scientists

Sensitivity of productivity and deep drainage of wheat cropping systems in a Mediterranean environment to changes in CO2, temperature and precipitation

Both anticipated climate change and dryland salinity pose a strategic threat to the sustainability of about 6 Mha of agricultural land in Western Australia (WA). These phenomena require an integrated analysis to estimate their potential impacts and initiate strategic thinking about adaptation. Water loss below the root zone, i.e. deep drainage, is the primary cause of sub-soil salt mobilisation leading to surface soil salinity in areas cleared of natural vegetation in Australia; hence deep drainage is an important externality of agricultural production. The purpose of this paper is to show how changes in CO2 concentration, temperature and precipitation may affect agricultural production and deep drainage. Results are presented of a simulation experiment with the Agricultural Production Systems Simulator (APSIM)-Nwheat model in which we explored sensitivity of (1) wheat production and quality, and (2) deep drainage, for three sites in WA differing in average precipitation, two soils, various nitrogenous fertiliser rates and present wheat cultivars. Since results of Global Circulation Models (GCM) are still largely inconsistent for this region, we have opted for a factorial approach in adapting 90 years of historical weather data. This set-up enabled separation of effects Of CO2, temperature, precipitation and their interactions, and unravelling of the complex interactions between water and nitrogen availability, phenological development and climate change factors, in the extremely variable Mediterranean climate in WA. Elevated CO2 concentration increased yields, particularly if nitrogen fertilisation was sufficient and conditions were relatively dry. Higher temperatures had non-linear effects, with initial (up to 3 degreesC) benefits on clay soils, but not on sandy soils, and then substantial yield declines. Both elevated CO2 concentrations and temperatures (+3 degreesC) decreased grain protein, but in financial terms this was more than offset by the increase in yield in most cases. If, in addition, precipitation was decreased, financial returns dropped below present levels, particularly in the low precipitation regions. Deep drainage tended to be slightly higher under elevated CO2 concentrations but when higher temperatures were also simulated this was reversed. Deep drainage was greatly reduced in the low precipitation scenarios. Evidently climate change is not only likely to affect productivity, but also deep drainage and hence dryland salinity. The impact can vary in direction such that both 'win-win' and 'lose-win' outcomes may occur, particularly depending on the relative change in precipitation. (C) 2003 Elsevier Science B.V. All rights reserved