The relationship between adaptation and mitigation in managing climate change risks: a regional response from North Central Victoria, Australia

摘要

This two-part paper considers the complementarity between adaptation andmitigation in managing the risks associated with the enhanced greenhouse effect. Part onereviews the application of risk management methods to climate change assessments.Formal investigations of the enhanced greenhouse effect have produced three generationsof risk assessment. The first led to the United Nations Intergovernmental Panel on ClimateChange (IPCC), First Assessment Report and subsequent drafting of the United NationsFramework Convention on Climate Change. The second investigated the impacts ofunmitigated climate change in the Second and Third IPCC Assessment Reports. The thirdgeneration, currently underway, is investigating how risk management options can beprioritised and implemented. Mitigation and adaptation have two main areas of complementarity. Firstly, they each manage different components of future climate-related risk.Mitigation reduces the number and magnitude of potential climate hazards, reducing themost severe changes first. Adaptation increases the ability to cope with climate hazards byreducing system sensitivity or by reducing the consequent level of harm. Secondly, theymanage risks at different extremes of the potential range of future climate change.Adaptation works best with changes of lesser magnitude at the lower end of the potentialrange. Where there is sufficient adaptive capacity, adaptation improves the ability of asystem to cope with increasingly larger changes over time. By moving from uncontrolled emissions towards stabilisation of greenhouse gases in the atmosphere, mitigation limitsthe upper part of the range. Different activities have various blends of adaptive andmitigative capacity. In some cases, high sensitivity and low adaptive capacity may lead tolarge residual climate risks; in other cases, a large adaptive capacity may mean thatresidual risks are small or non-existent. Mitigative and adaptive capacity do not share thesame scale: adaptive capacity is expressed locally, whereas mitigative capacity is differentfor each activity and location but needs to be aggregated at the global scale to properlyassess its potential benefits in reducing climate hazards. This can be seen as a demand formitigation, which can be exercised at the local scale through, exercising mrtigativecapacity. Part two of the paper deals with the situation where regional bodies aim tomaximise the benefits of managing climate risks by integrating adaptation and mitigationmeasures at their various scales of operation. In.north central Victoria, Australia, adaptation and mitigation are being jointly managed by a greenhouse consortium and acatchment management authority. Several related studies investigating large-scale revegetation are used to show how climate change impacts and sequestration measures affectsoil, salt and carbon fluxes in the landscape. These studies show that trade-offs betweenthese interactions will have to be carefully managed to maximise their relative benefits.The paper concludes that when managing climate change risks, there are many instanceswhere adaptation and mitigation can be integrated at the operational level. However,significant gaps between our understanding of the benefits of adaptation and mitigationbetween local and global scales remain. Some of these may be addressed by matchingdemands for mitigation (for activities and locations where adaptive capacity will beexceeded) with the ability to supply that demand through localised mitigative capacity bymeans of globally integrated mechanisms.