DRAFT
Adaptation to climate change starts with human–environment interactions developed to cope with climate variability: A risk management approach
Roger N. Jones1, Bo Lim2 and Ian Burton3
1CSIRO Atmospheric Research, Aspendale Victoria 3195 Australia
2UNDP National Communications Support Programme, New York 10017 USA
3Meteorological Service of Canada, Toronto
Abstract
The most commonly used methods for national vulnerability and adaptation (V&A) assessments are climate scenario driven, and focus on predicting future vulnerability based on biophysical aspects of change. By discounting the role of human behaviour in shaping contemporary responses to climate variability these methods have been unable to develop meaningful policy responses. This paper describes an approach designed to assist countries in assessing the impacts of, and developing adaptations to, climate change. The approach is vulnerability-based, emphasising human-environment interactions under current climate and climate change. It shifts from a linear, predictive climate changeimpactsadaptation methodology to one of risk assessment that integrates the biophysical and socio-economic interactions of an activity or system. The major questions under consideration are, 1) “To what extent will climate change alter the present range of impacts, increasing the risk of vulnerability?” and 2) “How best can development paths be modified to reduce current and future vulnerability to climate?” The starting point is the relationship between current climate, the ability to cope and vulnerability. Current climate variability and extremes are manifested as a coping range, encompassing existing adaptations with a residual range of vulnerability separated by a critical threshold. The degree to which climate change is likely to exceed a particular threshold will increase or decrease the exposure to climate-related risk for a particular activity or system. Adaptation needs are identified through critical threshold exceedance on an appropriate planning horizon and managed by shifting the coping range using planning and policy mechanisms. This approach is more robust than previous methods because it eschews a predictive methodology that analyses single pathways, towards a systems approach that endeavours to distinguish sustainable pathways amongst multiple possibilities.
Introduction
The Intergovernmental Panel on Climate Change’s (IPCC) Third Assessment Report (TAR) concludes that climate change is happening now and some sensitive systems are responding (IPCC, 2001b), and that serious and irreversible damages will occur within ranges of climate change projected for this century (IPCC, 2001a). These conclusions increase the need to develop policy for adaptation to climate change. Regional estimates of the magnitude and rate of climate change vary widely, implying a need for a “wait and see” approach until forecasts improve, but decisions that will be affected by climate change over their lifetimes are constantly being made. For example, many developments in the agricultural, water, urban, industrial and forestry sectors are constructed under assumptions of a stationary climate. In coming decades, these benefits may be severely limited or even reversed under climate change unless adequate modifications are put in place. Maladaptations (e.g. inappropriate forest clearance) may exacerbate climate risks. Potential opportunities may be missed (Yohe and Dowlatabadi, 1999). How do policy makers respond to a threat that is likely to occur but is highly uncertain in the way that it will manifest?
This problem is particularly acute for developing nations. Many developing nations are vulnerable to current climate (Smit and Pilifosova, 2001), most have highly variable climates and all are limited in their capacity to adapt to climate extremes. Despite limited contributions of historical greenhouse gas emissions, developing nations are highly vulnerable to future impacts (AOSIS, 1999; Apuuli et al., 2000). Increasing adaptive capacity to climate change is a development issue that competes for resources with other development issues, such as food security, social equity, education and health (Munasinghe, 2000; Rayner, 2000). Critics of international funds being spent on investigating long-term adaptation needs argue that reducing the substantial current vulnerabilities should take precedence (e.g. Kelly, 2000).
More than 100 National Communications containing vulnerability and adaptation (V&A) assessments have so for been submitted to the United Nations Framework for Climate Change (UNFCCC), but their impact on adaptation policy has been limited. Most of the V&A assessments were based on the seven step framework for impact assessment first described by Carter et al. (1994) and elaborated on in UNEP (1998) and Carter and Parry (1998). This method, referred to henceforth as the standard method, describes a cause and effect pathway that projects climate change scenarios through impact models then formulates adaptation measures. Different scenarios can lead to quite different adaptation strategies. Alternative approaches are to try and distinguish the most likely pathway (what will happen) or to distinguish desirable and undesirable pathways (what happens if). It is a linear methodology based on a causal chain of events, the results of which are conditional upon the input scenarios and generally limited to estimates of potential vulnerability. In this paper, we argue that the standard method has reached its limits of utility for policy formulation.
This linear structure has contributed to, then been further emphasised by, the organisational structure of the IPCC whereby Working Group I: The Scientific Basis feeds results onto Working Group II: Impacts, Adaptation and Vulnerability. Furthermore, vulnerability, impacts and adaptation are defined in the TAR as anomalies from the current state (see Box 1) overlooking the role of vulnerability and adaptation to current climate as the basis for recognising and addressing change.
Rather than addressing vulnerability addressed after moving from the physical environment to social impacts, Hewitt (1983), Rayner and Malone (1997) and Adger (1999) advocate defining vulnerability as the state of society–environment interactions under stress before determining how this stress may change. Barnett (2001) describes the standard methods, in their anticipation of impacts in an environment of uncertainty as unsuccessful, and suggests a strategy based on understanding of vulnerability/resilience to current climate, particularly to climatic extremes (see also Adger, 1996, 1999). While we agree in part with this approach, we propose a method by which the analysis of present day vulnerability informed by historical perspective (Adger, 1996), can be combined with specific methods for characterising risk under climate change in a manner consistent with Article 2 of the UNFCCC. A similar approach is recommended by Pielke and Bravo de Guenni (2002).
The approach presented in this paper is a contribution to the Adaptation Policy Framework currently being developed under the auspices of the UN Development Programme (UNDP). The Adaptation Policy Framework comprises five basic steps: scope project, assess current vulnerability, characterise future conditions, prioritise policies and measures and facilitate adaptation (Figure 1). We believe that the methods of characterising climate risk as described by this paper provide a way to manage the uncertainty of climate change by bringing together the social aspects of vulnerability, the technical requirements of climate impact assessment and the contingencies required of policy development. A full description of this framework and associated methods for application is currently being prepared (Burton, et al., in prep.).
We aim to augment and improve on the standard method of impact and adaptation assessment by incorporating the four following aspects:
- Changing the focus of assessment from a climate-based approach to a vulnerability-based approach.
- Managing uncertainty by moving from a predictive (prescriptive) approach to a risk-based (diagnostic) approach.
- Recognising the role of behaviour in adaptation by taking adaptations developed to cope with climate variability as the baseline upon which to adapt to climate change.
- Managing adaptation over appropriate time horizons, taking account of how both climatic and socio-economic changes may alter vulnerability.
Figure 1. Adaptation Policy Framework developed at the joint UNFCCC/UNDP GEF workshop in Canada, June 2001 with subsequent modifications.
Approach of the Adaptation Policy Framework
The standard method has successfully been used to assess the level of threat posed by enhanced climate change (see Watson et al., 1998; McCarthy et al., 2001). The knowledge that systems have always responded to climate, and that significant vulnerabilities are on the horizon, shifts the focus of adaptation assessments from “What are the potential adaptations to climate change” to “How do we adapt to climate change?” Instead of assessments generating information about potential adaptation, which is useful for inferring the need for mitigation, the demand is shifting to practical application, a far more difficult role. This moves the focus of adaptation frameworks away from scenario-based “what if” questions, towards providing guidance to policymakers.
The key issue for adaptation is not climate change itself but is vulnerability to climate change. Climate change is a significant global issue because of vulnerability. Vulnerability is a social response to climate change impacts and can be reduced by either adaptation, or mitigation. We build on the relationship between vulnerability, impacts and adaptation as described by Wheaton and MacIver (1999, based on Watson et al., 1996; Box 1) but also consider vulnerability, impacts and adaptation under current climate to show how adaptation can be used to reduce vulnerabilities to future climate over a variety of time scales. Adaptation to current climate is linked with a coping range of climate (Hewitt and Burton, 1971; Smit et al., 2000). By exceeding a critical threshold defining an unacceptable level of harm, climate occurrences beyond that range will result in vulnerability (Swart and Vellinga, 1994; Parry et al., 1996; Downing et al., 1997; Pittock and Jones, 2000). Future vulnerability is related to the changed frequency of threshold exceedance under climate change (i.e. over long-term planning horizons). The development of increased adaptive capacity to cope with future climate will be informed by the risk of threshold exceedance over the long-term, but will build on adaptive strategies developed to cope with current climate.
Better practical management of uncertainties by moving from a predictive approach to a risk-based approach. Uncertainty about climate change is unlikely to be significantly reduced in the short term, but neither can we adopt a “wait and see” strategy. Rather than trying to predict impacts through individual scenarios, we focus on the triggers, or critical thresholds, that signal a state of vulnerability. By using the same set of climate variables in threshold measurement, scenario construction and impact assessment it is possible to determine where a threshold is located within a range of future climate uncertainties. This approach to managing uncertainty does not reduce the total uncertainty, but establishes agreed goals around which it is possible to assess the overall risk of achieving (positive) or avoiding (negative) goals within the context of projected climate change (Jones, 2001).
Planned adaptation is a behavioural response to information about the future. Planned adaptation needs to take account of information about climate change and to develop appropriate behavioural responses, which will be based on current individual, community and institutional behaviour. Adaptation measures need to be consistent with current behaviour and future expectations if they are to be accepted by stakeholders. Existing adaptation is a response to the net effects of current climate (variability and change) as expressed by the coping range. An understanding of current adaptation capacity is necessary to understand current vulnerability. The analysis of behavioural responses to current climate variability also aids in the construction of climate scenarios.
Management over appropriate time horizons. If adaptive capacity is to be addressed in a proactive manner, both short-term and long-term vulnerabilities need to be managed (Adger and Kelly, 1999). Climate change will manifest over the coming decades but current vulnerabilities and national development plans will both manifest over the short term. Given the demands on limited available resources (financial, technological, human) in the context of human development, adaptation will need to demonstrate short-term gain, even if further benefits are expected over the long term.
Box 1. Definitions of vulnerability, impacts and adaptation as defined by IPCC (2001b)
Vulnerability(V)
The degree to which a system is susceptible to, or unable to cope with, adverse effects of climate change, including climate variability and extremes. Vulnerability is a function of the character, magnitude and rate of climate variation to which a system is exposed, its sensitivity, and its adaptive capacity.
Impacts (I)
Consequences of climate change on natural and human systems. Depending on the consideration of adaptation, one can distinguish between potential impacts and residual impacts.
Adaptation (A)
Adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderates harm or exploits beneficial opportunities. Various types of adaptation can be distinguished, including anticipatory and reactive adaptation, private and public adaptation, and autonomous and planned adaptation.
Adaptive capacity
The ability of a system to adjust to climate change (including climate variability and extremes) to moderate potential damages, take advantage of opportunities, or cope with the consequences.
Figure 2. Structure of vulnerability, impacts and adaptation where V and A are separated by a critical threshold, (Tc) marking the level where impacts result in an unacceptable degree of harm. IPCC (2001b) definitions imply the critical threshold is residual after adaptation whereas Pittock and Jones (2000) define the critical threshold in terms of recognising the need to adapt.
Adopting a Vulnerability-based Approach
This paper integrates the biophysical and socio-economic aspects of climate variability and change to develop an understanding of how climate risks may change over time, and to develop adaptation options to manage those risks. The basic unit is the coping range, which relates the major climatic drivers of a system with outputs that can be measured in terms of success or failure (Smit et al., 2000; Jones, 2001). The coping range is distinguished as a range of variability expressed in terms of climate or related system variable(s) that can be linked to climate, such as streamflow and water supply, agricultural yield, forestry yield or levels of income or profit. Within the coping range, conditions range from being desirable to tolerable levels of harm, while beyond the coping range, tolerance (and resilience) levels are exceeded. Combinations of climate variability and extremes can drive a system beyond its limit of tolerance, defined by a critical threshold (Smit and Pilifosova, 2001). Because the starting point for any adaptation is current behaviour, we analyse current climate vulnerability and how that vulnerability is managed before proceeding on to an assessment of future risks. This exploration is ideally carried out with stakeholders, and may result in different stakeholder-specific coping ranges for the one activity. For example, dryland and irrigation farmers have very different coping ranges with regard to seasonal rainfall, with dryland farmers requiring regular rainfall to maintain soil moisture while irrigators are more dependent on volume in storage and can cope with seasonal rainfall deficits.
The further climate change moves a system beyond its coping range, the greater vulnerability will be. This idea is encapsulated in Smith et al. (2001) and Figures 2 to 4. The most vulnerable systems will be those with critical thresholds that are exceeded at low levels of global warming. As global warming increases, the damage levels to many individual systems will increase and the number of systems at risk will also increase. Adaptation can reduce vulnerability by increasing the coping range, maladaptation will reduce that range. Changing adaptive capacity can also influence how the coping range evolves, independently of climate change (Smit et al., 2000; Yohe and Tol, 2002). Therefore, it is possible to investigate how climate and socio-economic factors influence the ability to cope with climate either individually, jointly as independent variables and as interacting variables.
By placing adaptations within a framework of evolving policy for sustainable development both short- and longer-term climate risks can be addressed. The major strategies for risk management are adaptation and mitigation. Management through adaptation requires a better understanding of adaptive behaviour in response to current climate risks, integrated with improved characterisations of risk and if adaptation under climate change. Mitigation will reduce the likelihood of climate breaching the coping range by reducing the rate and magnitude of climate change, but is not dealt with any further here.
Risk management through adaptation is consistent with Article 2 of the UNFCCC which aims to prevent dangerous anthropogenic interference with the climate system in terms of threats to (i) the natural adaptation of ecosystems, (ii) the maintenance of food security and (iii) economically sustainable development to proceed. However, in comparison to mitigation, which reduces climate on a global scale because of the rapid mixing of greenhouse gases in the atmosphere, adaptation is a bottom-up approach that needs to deal with system- and location-specific impacts. This approach also begins at the local level, rather than the standard approach which is downscaled from GCM output at the global level, so is more appropriate to the local scale (Pielke and Bravo de Guenni, 2002). We investigate local and regional systems to assess which activities are the most vulnerable and aim to reduce both current and future climate-related risks through adaptation. While many of the tools described here are utilised in the standard method, the overall approach is quite different, taking a system rather than a linear approach (Table 1).
Table 1. Table comparing the structure of the standard methods and adaptation policy framework. The key difference is that the standard method projects each discipline from now into the future separately, with each pass building on the last, whereas the APF builds an understanding of system specific links between the biophysical and socio-economic under current climate, then projects the whole structure through time.
Methodology / Structure / Begins / Builds / Moves forward / OutputStandard / Linear,
causal / Starting focus on climate change science / Builds from one discipline to the next / Builds layers that project forward in time: climate, biophysical impacts, socio-economic impacts, adaptation / Scenario-derived options for adaptation to future conditions, often based on biophysical impacts, delivered towards the end of the project
APF / System, relational / Starting focus on stakeholders’ experience of current climate / Builds using an interdisciplinary approach / Builds framework linking biophysical to socio-economic under current conditions, then projects the whole framework over planning horizons / Knowledge of current adaptations and adaptive capacity during the project, comparison of current and future climate risks mid project, options for policy, planning and management at the end
Characterising climate risk