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Background and Aims: A region's suitability for viticulture is commonly categorised by thermal‐based bioclimatic indices during the growing season, of which the growing season temperature (GST) is the most widely used. Growing season temperature thresholds, however, were developed for a specific region and therefore may not translate to other established wine regions, including Australia. This paper aims to investigate and refine the application of GST in modelling spatial suitability of existing wine regions in south‐east Australia. Methods and Results: Locations suitable for winegrapes according to traditional GST were mapped and compared with established wine regions. Inconsistencies were identified, and a range of refinements was applied in order to improve the spatial representation. Conclusions: This study highlights the benefit of three improvements to the GST parameter in order to successfully represent Australian wine regions. First, a latitude adjustment was applied to the GST to account for varying day length. Second, significant temporal variability in GST over the last 15–20 years was identified, highlighting the challenge of selecting a period that represents 'average conditions' for such studies. Third, in order to model the spatial extent of Australian wine regions, the inclusion of a 'hot' GST classification (19–22°C) was needed. Significance of the Study: These refinements allow for the successful quantification of climatic conditions for Australian viticulture. Refined GST thresholds can be applied to future climate projections, providing the industry with vital information and guidance on how to react and adapt to the challenges of climate change. [ABSTRACT FROM AUTHOR]

While winegrowers usually want to achieve consistent yield targets, there is a high degree of yield and price (and hence gross revenue) variability in winegrape production. The aim of this study was to determine whether there are differences in yield and revenue variability across climates, varieties, and regions in Australia. This was performed by estimating statistical models of the impact of these three variables on the coefficient of variation of yield and gross revenue per hectare. The results suggest that hotter and drier regions exhibit lower interannual yield variability, something that in the past may have been largely explained by the use of irrigation, but which may change in the future with climate change and higher water prices. The results also showed that there are sometimes differences in yield and revenue variability, not only across regions, but also between varieties. [ABSTRACT FROM AUTHOR]

Background and Aims: This paper describes the changes in temperature-based indices used to classify viticultural climates in Australia for three warming scenarios produced by the Commonwealth Scientific and Industrial Research Organisation: Mk3.0 global climate model for the years 2030, 2050 and 2070. Methods and Results: Temperature indices that describe grapevine growing season temperature (GST), ripening period temperature, accumulated biologically effective degree days and growing season length were calculated to produce maps of Australia for each warming scenario. Summary statistics of each index's median and range are presented for each Australian wine region under each warming scenario. The greatest change in GST (above the 1971–2000 mean) was modelled to occur for the Perth Hills region, increasing by 1.0°C by 2030, 1.9°C by 2050 and 2.7°C by 2070. The least change in GST was modelled to occur for the Kangaroo Island region, increasing by 0.5°C by 2030, 0.9°C by 2050 and 1.3°C by 2070. Conclusion: Of the 61 recognised wine regions, a median GST of over 21°C (an indicator of the limit of quality wine grape production conditions) was found for three regions for the period 1971–2000, for eight regions for the 2030 scenario, 12 regions for the 2050 scenario and 21 regions for the 2070 scenario. Significance of the Study: Without appropriate adaptations, some established viticultural regions of Australia may become less suitable for quality winegrape production, whereas regions that were once considered unsuitable for quality winegrape production may become more suitable. [ABSTRACT FROM AUTHOR]

Background and Aims: Cross‐sectional models are useful for estimating the impact that climate and climate change have on grape prices due to changes in grape composition. The aim of this study is to estimate the impact of growing season temperature (GST) on grape prices in Australia using cross‐sectional data. Methods and Results: We use data on average price by cultivar and region for a 10 year period. We estimate a model using (area‐) weighted least squares and variables from a principal component analysis to control for 103 characteristics that relate to the production system used in each of 26 regions. Results suggest that a GST increase of 1°C leads to a decrease of 9% in the average price of grapes. A LASSO model that we use as a robustness check suggests similar results: a GST increase of 1°C leads to a decrease of 7.3% in the average price of grapes. Conclusions: Failing to control for characteristics that relate to the production system overestimates the impact of GST on grape prices, suggesting that changes to variables in a production system may mitigate deleterious changes to grape composition due to climate change. Significance of the Study: This study contributes to the understanding of the issue of omitted variable bias in cross‐sectional models, and how to deal with this issue when analysing the impact of climate and climate change in grape and wine research. [ABSTRACT FROM AUTHOR]

Background and Aims: Predicted impacts of climate change—increased temperature, decreased rainfall, and reduced water availability—are expected to increase irrigation‐related salinity in Australia's major wine regions. Breeding of new abiotic stress‐tolerant rootstocks will help to mitigate these effects on viticulture. Here, we investigated the impact of elevated temperature on key salt tolerance traits of two contrasting rootstocks and a population of experimental rootstock hybrids. Methods and Results: A high‐throughput facility was used to phenotype the rootstocks, K51‐40, 140 Ruggeri and 68 K51‐40 derived hybrids, all ungrafted, under factorial salinity and temperature treatments. Elevated temperature led to increased chloride concentration in the mature laminae of most genotypes, likely driven by increased transpiration, with large differences between genotypes in the extent of the temperature response. Genetic differences were also observed for the influence of temperature on laminae sodium accumulation. Growth rate response to salinity was variable between genotypes and was independent of laminae chloride and sodium accumulation. Conclusions: High‐throughput phenomics provides a promising tool to simultaneously assess new rootstock selections for ion exclusion and growth rate response under abiotic stresses. Significance of the Study: Understanding the effect of temperature on salinity tolerance traits, and the development of novel screening tools, will help breed new rootstocks better suited to a hotter and drier future climate. [ABSTRACT FROM AUTHOR]

Background and Aims: Declining autumn and winter rainfall increasingly limits soil moisture availability at the onset of the growing season in southern Australia. We studied the consequences of reduced rainfall during dormancy on vine growth, and explored irrigation strategies to maintain yield following dry winters. Methods and Results: The effect of the timing and method of irrigation during dormancy on vine performance was investigated for three seasons in a Shiraz vineyard where late autumn and winter rainfall was excluded using shelters. Reduced soil moisture in spring delayed the time of budburst. A reduction in rain to approximately one third of the historical average reduced yield (24–42%) and canopy size (16–31%). Natural rain (Control) or equivalent sprinkler irrigation, providing water during winter, resulted in a higher yield: pruning mass ratio, but reduction in yield was still observed when drip irrigation was used to replace winter rain. Refilling the soil profile in spring after dry winters favoured growth partitioning towards canopy and roots, increased carbohydrate reserves in the trunk, but reduced yield (−10 to −32%). Conclusions: Irrigation during winter did not fully offset the decline in production. Refilling the soil profile at the end of winter increased vigour, and reduced yield. Reduced soil moisture prior to spring delayed the time of budburst. Significance of the Study: Vineyard management aiming to sustain yield under a changing climate will need to incorporate winter irrigation. Models predicting the time of budburst under a changing environment could be fine‐tuned by incorporating soil moisture availability. [ABSTRACT FROM AUTHOR]

Background and Aims: Grapevine phenology is closely linked with growing season temperature. Rising temperature related to anthropogenic climate change has the potential to advance winegrape ripening. This study updated and validated previous research that considered changes to the timing of winegrape maturity and to the warming temperature of the growing season as well as added several new vineyard data sets. Length of the harvest period was assessed to determine if time between harvests of different cultivars has shortened. Methods and Results: Vineyard records from 31 vineyard blocks in 13 Australian wine regions, in conjunction with gridded temperature data, were used to assess changes to maturity timing and mean growing season temperature. Trends towards earlier maturity were evident as were increases to mean growing season temperature for all vineyard blocks and regions considered. Trends varied in magnitude as well as by cultivar and region. Compression of the harvest period occurred for half of the regions studied. Conclusions: Winegrape maturity in Australia has continued to advance in line with warming temperature, which has implications for grape composition and wine quality. Compression of the harvest period was found in some cases, though varied by region and cultivars grown. Significance of the Study: This study validated the trend towards earlier winegrape maturity with continued warming temperature and extended a valuable phenological data set. In light of record warming, earlier maturity is becoming the new norm. The method used to investigate compression of the harvest period in this study is applicable to other winegrowing regions worldwide. [ABSTRACT FROM AUTHOR]

The challenges that climate change poses for marine ecosystems are already manifesting in impacts at the species, population, and community levels in Australia, particularly in Tasmania and tropical northern Australia. Many species and habitats are already under threat as a result of human activities, and the additional pressure from climate change significantly increases the challenge for marine conservation and management. Climate change impacts are expected to magnify as sea surface temperatures, ocean chemistry, ocean circulation, sea level, rainfall, and storm patterns continue to change this century. In particular, keystone species that form the foundation of marine habitats, such as coral reefs, kelp beds, and temperate rocky reefs, are projected to pass thresholds with subsequent implications for communities and ecosystems. This review synthesises recent science in this field: the observed impacts and responses of marine ecosystems to climate change, ecological thresholds of change, and strategies for marine conservation to promote adaptation. Increasing observations of climate-related impacts on Australia'smarine ecosystems--both temperate and tropical--are making adaptive management more important than ever before. Our increased understanding of the impacts and responses of marine ecosystems to climate change provides a focus for "no-regrets" adaptations that can be implemented now and refined as knowledge improves. [ABSTRACT FROM AUTHOR]

During the last sixty years, there have been large changes in the southern hemisphere winter circulation and reductions in rainfall particularly in the southern Australian region. Here we examine the corresponding changes in dynamical modes of variability ranging from storm tracks, onset-of-blocking modes, northwest cloud-band disturbances, Antarctic low-frequency modes, intraseasonal oscillations, and African easterly waves. Our study is performed using a global two-level primitive equation instability-model with reanalyzed observed July three-dimensional basic states for the periods 1949-1968, 1975-1994, and 1997- 2006. We relate the reduction in the winter rainfall in the southwest of Western Australia since the mid-1970s and in south-eastern Australia since the mid-1990s to changes in growth rate and structures of leading storm track and blocking modes. We find that cyclogenesis and onset-of-blocking modes growing on the subtropical jet have significantly reduced growth rates in the latter periods. On the other hand there is a significant increase in the growth rate of northwest cloud-band modes and intraseasonal oscillation disturbances that cross Australia and are shown to be related to recent positive trends in winter rainfall over northwest Western Australia and central Australia, in general. The implications of our findings are discussed. [ABSTRACT FROM AUTHOR]