11.7 Conclusions: implications for sustainable development

An assessment of aggregate vulnerability for key sectors of the region is given in Figure 11.4, as a function of potential global warming. It synthesises relevant information in Sections 11.2 to 11.5 about current sensitivity, coping ranges, potential impacts, adaptive capacity and vulnerability. It follows similar diagrams and concepts published elsewhere (Jones et al., 2007) and emulates the ‘Reasons for Concern’ diagram (Figure SPM-3) in the TAR Synthesis Report. Since most impact assessments in the available literature do not allow for adaptation, the yellow band in Figure 11.4 is indicative only. In line with Chapter 19, vulnerability is assessed using criteria of: magnitude of impact, timing, persistence and reversibility, likelihood and confidence, potential for planned adaptation, geographical distribution and importance of the vulnerable system. Ecosystems, water security and coastal communities of the region have a narrow coping range. Even if adaptive capacity is realised, vulnerability becomes significant for 1.5 to 2.0°C of global warming. Energy security, health (heat-related deaths), agriculture and tourism have larger coping ranges and adaptive capacity, but they become vulnerable if global warming exceeds 3.0°C. The three key vulnerability factors identified in Article 2 of the United Nations Framework Convention on Climate Change (UNFCCC) – natural ecosystems, sustainable development and food security – are also shown in Figure 11.4.

Figure 11.4. Vulnerability to climate change aggregated for key sectors in the Australia and New Zealand region, allowing for current coping range and adaptive capacity. Right-hand panel is a schematic diagram assessing relative coping range, adaptive capacity and vulnerability. Left-hand panel shows global temperature change taken from the TAR Synthesis Report (Figure SPM-6). The coloured curves in the left panel represent temperature changes associated with stabilisation of CO₂ concentrations at 450 ppm (WRE450), 550 ppm (WRE550), 650 ppm (WRE650), 750 ppm (WRE750) and 1,000 ppm (WRE1000). Year of stabilisation is shown as black dots. It is assumed that emissions of non-CO₂ greenhouse gases follow the SRES A1B scenario until 2100 and are constant thereafter. The shaded area indicates the range of climate sensitivity across the five stabilisation cases.

The narrow bars show uncertainty at the year 2300. Crosses indicate warming by 2100 for the SRES B1, A1B and A2 scenarios.

When these climate change impacts are combined with other non-climate trends (see Section 11.3.2), there are some serious implications for sustainability in both Australia and New Zealand. Climate change is very likely to threaten natural ecosystems, with extinction of some species. There are limited planned adaptation options, but the resilience of many ecosystems can be enhanced by reducing non-climatic stresses such as water pollution, habitat fragmentation and invasive species. In river catchments, where increasing urban and rural water demand has already exceeded sustainable levels of supply, ongoing and proposed adaptation strategies (see Section 11.2.5) are likely to buy some time. Continued rates of coastal development are likely to require tighter planning and regulation if they are to remain sustainable. Climate change is very likely to increase peak energy demand during heatwaves, posing challenges for sustainable energy supply. A substantial public health and community response is likely to be needed in order to avoid an increase of several thousand heat-related deaths per year.

Large shifts in the geographical distribution of agriculture and its services are very likely. Farming of marginal land in drier regions is likely to become unsustainable due to water shortages, new biosecurity hazards, environmental degradation and social disruption. In areas that are likely to become wetter and less frosty, it may be possible to grow new crops or those displaced from other regions. Adaptation has the capacity to capture these benefits; they are unlikely to accrue without investment in the adaptation process. Food security is very likely to remain robust, with both countries able to produce more food than they require for internal consumption, although imports of selected foods may be needed temporarily to cover shortages due to extreme events. Climate changes are also likely to bring benefits in some areas for hydro-generation, winter heating requirements and tourism.

Figure 11.5 assesses key hotspots identified for the region, where vulnerability to climate change is likely to be high. Their selection is based on the following criteria: large impacts, low adaptive capacity, substantial population, economically important, substantial exposed infrastructure and subject to other major stresses (e.g., continued rapid population growth, ongoing development, ongoing land degradation, ongoing habitat loss, threats from rising sea level). Their development at current rates and accustomed supply of ecosystem services are unlikely to be sustainable with ongoing climate change, unless there is considerable planned adaptation.

Figure 11.5. Key hotspots identified for Australia and New Zealand, assuming a medium emissions scenario for 2050.

For Australia and New Zealand, the magnitude of investment in adaptation is overshadowed by that in mitigation. The latter is intended to slow global warming. However, there is unlikely to be any noticeable climate effect from reducing greenhouse gases until at least 2040 (see Chapter 18). In contrast, the benefits of adaptation can be immediate, especially when they also address climate variability. Many adaptation options can be implemented now for Australia and New Zealand at personal, local and regional scales. Enhancing society’s response capacity through the pursuit of sustainable development pathways is one way of promoting both adaptation and mitigation (see Chapter 18).