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Adaptation to Climate Change: Inciting yet another Top-Down/Bottom-Up debate.

Written by Kilian Raiser


In 2000, biologist Eugene Stroemer and Nobel-Chemist Paul Crutzen advanced the term ‘Anthropocene’ (Scranton, 2013). Since then there has been wide acceptance of the notion that we are indeed living in a time where the predominant driver of change is human activity (Rockstrom et al. 2009). The Intergovernmental Panel on Climate Change (IPCC, 2013), in their most recent report, presents substantial evidence that anthropogenic climate change will happen and is indeed happening.

O’Brien et al. (2007) argue that the increasing confidence with which climate scenarios are presented has resulted in a substantial increase in the attention given to adaptation.

“It has become clearer that some degree of climate change is inevitable regardless of mitigation efforts” (O’Brien et al. 2007, Pg. 83)

Heltberg et al. (2008) define adaptation as: “adjusting to address ongoing and future climate changes” (pg. 89). Smit and Pilisova (2001) expand on this by focusing adjustments on “Ecological, social and economic systems” (pg. 881). Furthermore they state that adaptation can be a response to “actual or expected” stimuli (pg. 881). There is a substantial difference in adaptation approaches, depending on whether adjustments are made to actual, or expected, stimuli. This essay will analyze this difference in approach, by reviewing the effectiveness of ‘Top-Down’ and ‘Bottom-Up’ approaches to adaptation, and the divide in the definition of the ‘vulnerability’ they address.

Definitions and Key Concepts


The IPCC define vulnerability as: “the degree to which geophysical, biological and socio-economic systems are susceptible to, and unable to cope with, adverse impacts of climate change” (IPCC, 2007)

Top-Down Adaptation:

Adger and Kelly (2000, pg. 326) define Top-Down adaptation as: “The end point of a sequence of analyses beginning with projections of future emission trends, moving on to the development of climate scenarios, and thence to biophysical impact studies and the identification of adaptive options”. Parry and Carter (1998) further reason that this approach relies on future climate predictions dependent on climate models based on greenhouse gas emissions. This paper focuses on the reliance of top-down approaches on climate scenarios, hence taking this as the defining factor of the approach

Bottom-Up Adaptation:

Bottom-Up adaptation is focused predominantly on the notion of vulnerability. Burton et al. (2002) claim that this approach assumes that if one can address actual vulnerability today, one inevitably reduces future (expected) vulnerability. O’Brien et al. (2007) expand on this by claiming that Bottom-Up approaches consider vulnerability as: “a characteristic of social and ecological systems that is generated by multiple factors and processes” (pg. 75). These factors can be defined as: wealth, health and educational status, social equity, food reliability etc. (Brooks et al. 2005)

The difference in adaptation approaches highlight the existing divide in interpretations of vulnerability. O’Brien et al. (2007) present vulnerability as either ‘Outcome-Vulnerability’ or ‘Contextual-Vulnerability’, relating each respectively to either a scientific (impact predictions) or human-security framing (actual vulnerability). Brooks (2003) highlights that vulnerability can be seen: “(i) in terms of the amount of (potential) damage caused to a system by a particular climate-related event or hazard, or (ii) as a state that exists within a system before it encounters a hazard event”, in effect claiming that vulnerability can either be ‘actual’ or ‘expected’.

“The interpretation of vulnerability affects the type of adaptation that is promoted (Burton and Huq, 2003)” (O’Brien et al. 2007, pg. 84)

Figure 1 provides a visual representation of the two approaches. This paper will review, in greater depth, each of these approaches. It will analyse the utility of climate scenarios, and thus top-down approaches, given the criticisms of both top-down and bottom-up methods. Furthermore it will look at the possibilities for combining the two.


Figure 1: Possible Top-Down Bottom-Up Integration (Dessai and Hulme, 2004)

Top-Down Approaches

Heavy reliance on climate models has come under much scrutiny from the academic world. As Dessai et al. (2009, pg. 64) point out, adaptation policy is subject to the claim; “that decision-makers need accurate, and increasingly precise, assessments of the future impacts of climate change in order to adapt successfully”. It is further argued that due to policy makers inability to work with the high level of uncertainty involved in top-down adaptation approaches, much of the research in this field stops at the impact assessment stage (Dessai and Wilby, 2010). Nonetheless, Dessai and Wilby (2010) claim that top-down approaches remain the most widely referenced approach within IPCC reports. Much of these strategies, however, are limited to developed nations. Developed nations are at an advantage as they are more resilient to climate change impacts (Dessai and Hulme, 2004). Much of the structural vulnerability addressed through bottom-up approaches is less of a consideration in developed nations as the infrastructures needed to adapt to climate changes are already in place.

In the UK, a study of the River Itchen provided evidence that: “the low flows – which are critical to the survival of iconic species such as salmon – are on average expected to decrease by just 2% by the 2020s” (Dessai and Wilby, 2010, pg. 182). Although the studies confidence interval lies between +4% and -24%, using a worst estimate, one can identify the maximum amount of deployable water available, allowing this data to be incorporated into the water utilities’ 25-year plans. However, much of the river was already designated as a conservation area, and thus does not necessarily sustain large populations’ livelihoods (Wildlife Trust, 2013). This example shows how, when the livelihoods of people are not directly at risk, top-down approaches can successfully contribute to adaptation strategies. However, the implications of this study change significantly if the river Itchen were the main source of fresh water for a contextually vulnerable community. The use of a worst case scenario could imply a considerable impact of adaptation on peoples’ livelihoods. However, in the best-case scenario the river flows increase. How can stakeholders utilize this information to adapt effectively?

Kwadijk et al. (2010) argue that, even within the developed/resilient world, top-down approaches are not always appropriate as they are limited by the complexity of the different models provided. Furthermore, Wilby and Harris (2006) found that the results of a study on summer flows of the river Thames were ranged between -19% and +74%. Given these divergences, Dessai and Hulme (2004) argue that: “Divergent results render a risk-based analysis extremely difficult because stakeholders are left wondering whether they should be prepared for more drought-like conditions or for wetter conditions” (Dessai and Hulme, 2004, pg. 4).

Van Pelt and Swart (2011) argue that long-term scientific projections do not consider the short-term goals of most governments. Whilst the scientific community models global climate patterns over the next century, many governments are more interested in local short-term impacts, and thus may be more suited to implementing a bottom-up approach.

Finally, Brooks (2003) criticizes the top-down focus on outcome vulnerability, as it “leads to the danger that adaptation is reduced to building local capacity to make sectorial and technological changes, rather than addressing the fundamental causes of vulnerability, including the geopolitical and economic contexts” (O’Brien et al. 2007, pg. 84).

Whilst this paper has criticized the use of climate scenarios within adaptation approaches, it is important to recognize their substantial contribution to conveying a scientific understanding of climate change to a global political scale.

Bottom-Up Approaches

Top-down adaptation approaches focus on a relationship between decision makers and the scientific community. However many argue that development agendas must play an increasing role if adaptation is to be effective (Heltberg et al. 2008). Halsenaes and Traerup (2009) argue that adaptation is fundamentally linked with key development areas such as; food security, robust education and health systems, and an improvement in infrastructure provision. Stern (2007) stresses that achieving these development goals will help in reducing vulnerability to climate change. Given the issues with uncertainties of climate models, basing adaptation strategies on achieving development goals that decrease vulnerability towards climate change makes sense (Dessai and Wilby, 2010).

“An approach focused on robust decision-making is less likely to be constrained by epistemological limits and therefore more likely to succeed than an approach focused on optimal decision-making predicated on the predictive accuracy of climate models” (Dessai et al. 2009, pg. 64)

Walshe and Nunn (2012) studied a case of disaster management in the Pacific Islands of Vanuatu. Using indigenous knowledge, the islands’ inhabitants were able to effectively recognise the indicators of an oncoming tsunami following an earthquake. Due to this they were able to evacuate the villages to higher ground. They conclude that; “This study has highlighted the importance of indigenous knowledge and its value in engaging peripheral communities in developing countries in disaster risk management, which is being increasingly acknowledged as central to development agendas (Mercer et al. 2007; Mercer et al. 2010)” (pg. 7). Although tsunamis cannot be directly linked to climate change, the approach taken in this study can be used as an allegory for the ability to substitute climate scenarios for other approaches.

Furthermore, a study on flood and drought vulnerability of villages in Mozambique by Eriksen and Silva (2003) highlights the need to address the process and inequities that exclude the most vulnerable from being able to cope with climate stress, both financially and physically. The success of the approaches studied is not limited to the developing world. Naess et al. (2005) stress that top-down flood defense mechanisms in the Netherlands, have undermined the local peoples capacity to develop more robust coping mechanisms.

Although these successes underline the advantage of bottom-up adaptation, Dessai and Wilby (2010, pg. 181) stress that “conventional vulnerability assessments, are less suited to guiding adaptation if coping thresholds change, or climate risks emerge that are outside the range of recent experience”. Furthermore it is argued that bottom-up cases are limited in their applicability outside of their specific context (Meyer er al. 1998) and do not consider the long-term implications of climate-change (Dessai and Hulme, 2004).

Combining the Two

From the evidence provided it is clear that there are significant advantages to bottom-up approaches over top-down approaches. Perhaps most strikingly, the ability of bottom-up strategies to result in a “win-win” scenario between climate change resilience and well-being development provides a strong argument for this approach.

However, whilst climate scenarios inherently come with a certain level of uncertainty, the increasing confidence of IPCC evidence provides testimony to the technological potential within climate predictions. Iizumi et al. (2013, pg. 904) reveal that “the use of seasonal climatic forecasts to predict crop failures will be useful for monitoring global food production and will encourage the adaptation of food systems to climatic extremes.”

Bhave et al. (2013) study the applicability of a combination of top-down and bottom-up approaches to the Kangsabati river catchment in India. Through the use of climate predictions they were able to include stakeholders in the decision making process. These tended towards bottom-up adaptation options, however their priorities were affected by the involvement of future predictions. They conclude “that such a combined approach is valuable for policy makers as it provides relevant assessment of adaptation options in the face of uncertain future climactic conditions whilst maintaining much needed legitimacy through stakeholder involvement” (pg. 12).

Dessai et al. (2005) studied the applicability of three varying approaches to adaptation. They found that there is a considerable amount of co-evolution between the various strategies. They identify a range of factors that determine which approach may be most suited. These include “spatial and temporal scales at which adaptation is taking place, availability of technical and financial capacity to handle scenario information and the type of adaptation being considered” (pg. 96). They reason that all methods, and any combination of them, are applicable when best suited to the context. However, they maintain that the main challenge faced is the integration of contextual concerns such as scale and capacity into climate impact scenarios.

These studies highlight the substantial “grey” area between the “black vs. white” debates on adaptation approaches. It can be argued that whilst each has its merits individually, when utilized effectively together, they enable a much more thorough examination of adaptation possibilities, considering a wider array of vulnerabilities, and the solution to these.


Following the arguments made: the extensive level of uncertainty associated with a climate scenario led approach creates a strong argument for the implementation of bottom-up approaches. This is further supported by the imperative development agenda within bottom-up strategies.

There does however seem to be a place for top-down management of adaptation issues. The increasing accuracy of climate and impact models steadily enhances their accessibility to decision makers. Furthermore their increasingly high spatial definition allows them to be applied at an increasingly local level. Finally they provide an insight, however uncertain, into possible future outcomes. Considering whether or not climate models are imperative to adaptation concerns, the current answer would most likely be no. However, climate and impact scenarios are able to provide decision-makers, and potential stakeholders, with information that may influence their adaptation priorities, and as these models improve, they will undoubtedly be an increasing help in considering the long-term applicability of adaptation approaches.

In conclusion, whilst adaptation measures should focus primarily on bottom-up solutions, climate scenarios provide a powerful technological tool to further our understanding of the possible implications of climate change. However uncertain, preparation for increasingly likely extremes is always a good idea.

© Kilian Raiser


About Kilian Raiser

Having grown up in diplomatic communities and subsequently studied at the United World College of the Atlantic, Kilian has alway been involved with global issues, especially climate change. He is particularly interested in Urban Planning and Policy. Kilian loves engaging in political and philosophical conversation, and is constantly in search for new opinions and interesting discussions. Otherwise Kilian can be found composing music or practicing with his band, he is also a passionate cook, and wishes he would/could spend more time outdoors, especially in the alps.

One comment on “Adaptation to Climate Change: Inciting yet another Top-Down/Bottom-Up debate.

  1. MonkeyM
    April 25, 2015

    This article is really useful, and also i think that only bottom-up (or only top down model) is not good enough to coping with climate change issues within different situations.

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