Significant knowledge gaps have become apparent during this assessment. These gaps mean that the net cost or benefit of unmitigated climate change in Australia and New Zealand is highly uncertain (see Section 12.9.1) and cannot be compared objectively with the cost of mitigation. Without this knowledge base, policymaking regarding adaptation and mitigation cannot be soundly based on economic considerations. Research priorities follow.
Indicators of climate impacts: Although long-term monitoring programs are in place for physical indicators (such as climate variables and sea level), work is still desirable on designing and implementing long-term monitoring programs that cover vulnerable animals, plants, and ecosystems and systematically examining them for the effects of climate changes. Flora and fauna with presently restricted or marginal climatic ranges would be most appropriate (see Section 12.4). (Candidate indicators for the UK are presented in Cannell et al., 1999.)
Underpinning physical knowledge and improved scenarios: Improved impact assessments will depend on better understanding of how climate change may influence factors such as the frequency and intensity of El Niños and related droughts, the intensity and location-specific frequency of tropical cyclones, and return periods for heavy rainfalls, floods, high winds, and hail. Oceanic issues include understanding differences between observed and modeled lag in warming of the Southern Ocean (see Section 126.96.36.199), possible impacts of cessation of bottomwater formation (see Section 12.4.7), and determining the influence of greenhouse warming on currents, upwelling, and nutrient supply. More knowledge is needed about influences of GHG-related cooling in the stratosphere on ozone depletion and regional UV radiation levels (see Section 12.7.1). All of this knowledge is needed to improve scenarios of regional climate (including ocean behavior).
Underpinning biological knowledge: The sensitivities of many plant and animal species and ecosystems in this region to climate changes, as well as the potential threats to biodiversity, are still unknown (see Section 12.4). Knowledge is required for assessment of potential impacts and for development of conservation strategies. This is important for marine and coastal environments, including coastal freshwater wetlands (see Section 12.4.7), as well as for terrestrial systems. Identification of relevant climatic thresholds for biological (and other) systems is needed (see Section 12.8.2). The effects of the time-varying balance between the beneficial physiological effects of increasing CO2 concentrations and climate change on natural (indigenous) and managed ecosystems needs to be better understood, especially in light of recent regional scenarios.
Underpinning social knowledge: Better knowledge is required about the vulnerability of particular population groups (including indigenous people), about how people and organizations have adapted to past climate variability and changes, and about public attitudes to adaptation and mitigation options. Work is needed to understand how different socioeconomic futures (demography, economic capacity, and technological change) (see Section 188.8.131.52) would affect vulnerability (see Sections 12.8 and 184.108.40.206) and on socioeconomic thresholds for change, such as economic nonviability and unacceptable risk.
Fisheries: There is insufficient information to enable confident predictions of changes in fisheries productivity from climate change (see Section 12.5.5). This requires better knowledge of physical and biological processes in the ocean (as above) and improved information on the climate sensitivities of many species.
Health: Continuing work is needed on the potential for introduction (New Zealand) and spread (Australia) of significant disease vectors, including sensitivity to climate, population shifts, and effectiveness of health services and biosecurity procedures (see Section 12.7.4). Other health issues should be addressed, including potential effects of threats to water supply on remote communities (see Section 12.7.6).
Regional effects and integration: Better quantitative sectoral knowledge is required about, for example, influences of climate change on water supply and demand (see Section 12.3.1), salinization (see Section 12.3.3), and some crops and farming practices (see Sections 12.5.2 and 12.5.3). Because various sectors (e.g., agriculture, ecosystems, infrastructure, and hydrology) interact at the regional and national levels, continued work is needed on integrated assessment approaches and models that synthesize sectoral knowledge and draw on the social sciences (see Section 12.8.2), in rural and urban settings. Models of the physical economy that track fluxes and pools of materials, energy, land, and water are required for national analyses.
Global interactions: More understanding is needed of the interaction of global climate change impacts, and of mitigation policies, on Australian and New Zealand markets, sectoral change, and land use (see Sections 12.5.9 and 12.8.7).
Adaptation: Further objective studies are required, in close collaboration with stakeholders, on adaptation options and their acceptability, costs, co-benefits, side effects, and limits (see Section 12.8). Adaptation should be regarded as a means to maximize gains and minimize losses, with a greater exploration of opportunities (see Section 12.8.1).
Costing: More comprehensive and realistic costings are needed for impacts and adaptation options, taking account of human behavior and using up-to-date scenarios.
Communication of policy-relevant results: If climate change issues are to be addressed by decisionmakers, there will need to be better communication of results from research. This will come partly from consultation with decisionmakers and other stakeholders to ensure that the right policy-relevant questions are addressed (see Sections 12.8.2 and 12.9) and partly from effective communication of what is known, as well as the uncertainties. A risk-assessment approach geared to particular stakeholders seems likely to be most effective (see Section 12.9.5).
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