Categorized | Climate Change

Bottom-up and top-down approaches in climate adaptation strategies

In a just published article, Bodansky (2011) makes a comparison and subsequent analyses of the different approaches taken by the United Nations in tackling emissions reductions.  The Kyoto Protocol, adopted in 1997 and entered into force in 2005, is, according to the author, a typical top-down mechanism, in which actions are determined by the U.N. itself and nations do not have the freedom or flexibility to define their emissions reductions commitments (although they can decide how to implement those).  In contrast, the Copenhagen Accord and the Cancun Agreements (from 2009 and 2010, respectively) are viewed as a more bottom-up approach, where the focus is on nationally-defined measures, and nations are allowed to define commitments and actions, and make pledges unilaterally.  He goes on to discuss the pros and cons of each approach, and how some sort of combination of both might lead to better results in the long run – a collective agreement but more individual flexibility.

Bottom-up and top-down approaches are widely used in traditional sciences.  For instance, when studying community ecology, researchers speak of bottom-up and top-down forces shaping the community, and how the outcomes of those processes may differ.  A very simplistic example of a bottom-up force affecting a community is the availability and abundance of plants, which are then consumed by the herbivores, the carnivores, etc.  This bottom-up force shapes the community because the latter will be composed of the organisms able to live off of whatever plant resources exist, in a food web-type manner.  An example of top-down force would be predators.  Those components of the community, depending on their type and numbers, will have an impact on the prey population, which in turn will have an effect on other animals and the plant community.  Ideally, those two forces are constantly in action, acting simultaneously to keep the community in a state of dynamic equilibrium.

Climate science is no different.  In the context of climate science, various components such as mitigation and adaptation strategies to cope with a varying climate must be identified and implemented.  The approaches to those actions can also be seen as bottom-up or top down.  According to Glick et al. (2011), a top-down approach, much like the Kyoto Protocol, looks at global-scale possible scenarios under a variable climate, such as sea-level rise or extreme climatic events.  Once the scenario is determined, organizations look into how that scenario might affect the landscape, and identify strategies to address those possible changes.  A bottom-up approach, similarly to the Copenhagen Accord and Cancun Agreement, starts with a specific goal, such as reducing pollutant levels or protecting critical habitat.  However, from there, organizations can independently identify how climate can affect those goals, determine possible outcomes, and individually come up with options for reducing whatever negative effects could be foreseen.

Traditional science has shown that both approaches are valid and can co-exist.  In climate science, the same should be possible.  Which approach is used depends on factors such as the scale of the strategy, as well as resources (human and financial), stakeholder interests, stated goals and objectives, and various other constraints that include but are not limited to geographical, socio-economical, geological, and ecological.  The top-down approach may be more appropriate for large-scale adaptation strategies, while bottom-up approaches can be used to fine-tune conservation efforts within a smaller area, for example.  Conservation organizations and agencies should determine the best approaches, and work with both to achieve the ultimate goal of conserving important ecosystem services, habitats, and wildlife in the face of a changing climate.

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Astrid Caldas is the Climate Change & Wildlife Science Fellow for Defenders of Wildlife. Astrid provides scientific support for Defenders, including providing technical assistance for integrating climate adaptation into programs, doing synthetic research, and publishing papers and reports on climate and wildlife issues.

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