Early Adaptation to Avoid Collapse in Ecosystems, Services and Communities
By Michael Dunlop, CSIRO Climate Adaptation Flagship
Commentaries were commissioned by the World Resources Report to react to the Expert Perspectives series. This commentary responds to Question 4: Must we fundamentally change course to conserve ecosystems in a changing climate?
The four discussion papers in this series highlight some of the challenges of managing ecosystems in a changing climate. They especially highlight the vulnerability of people who are dependent on natural ecosystems and the services they provide. The argument is put that, in the face of multiple threats to ecosystems, increased security of access to ecosystems services will better enable the vulnerable to adapt to climate change. Further, it is argued that better conserving the world’s ecosystems will also help reduce the rate of net emissions of green house gasses. With these motivations the four papers argue for various approaches to conserving ecosystems that are “fundamentally different” to the approaches that have, in the main, failed in the last decade. In essence, all four papers argue for a much greater articulation and institutional recognition of the many ways that ecosystems provide value, and the likelihood of the importance of those values increasing under climate change.
I would like to focus slightly more on ecosystems and the species making them up, and highlight some issues from that perspective that I believe have significant implications for the conservation of natural ecosystems and people relying on those ecosystems for their livelihoods.
Species sensitivity to climate change
There is a substantial amount of observational and modeling evidence for the sensitivity of species to climate change, most of which highlights the phenomena of species distributions moving in response to shifting bioclimatic environments, and changes in the seasonal timing of migrations and various life history events. There is also a growing body of observations, experiments and ecological analyses articulating other change phenomena. The lessons, to date, from all this work, are that:
- there are many likely responses of species and ecosystems to climate change;
- individual species will respond in different ways, leading to altered species interactions, dissolution of existing ecological communities and formation of novel ones, and widespread changes in ecosystem composition, structure and function, including primary productivity;
- while we are certain that species and ecosystems are sensitive to changing climates, there is considerable uncertainty about the details of the changes that can be expected and the particular service affected; and
- recently observed rates of climate change, and better understanding of the sensitivity of biodiversity, suggest that the level of impact on ecosystems will be substantial and near-term.
Together these lessons suggest that people managing and benefiting from ecosystems will be facing transformations in ecosystems not marginal changes. While it is difficult to quantify, the expected changes in ecosystems are highly likely to lead to substantial changes in the nature and amount of ecosystem services provided. Those people dependent on ecosystems will therefore need to adapt to both new ecosystem services and different regimes in their availability; for example, changes in food species, reduced availability of food and other resources, and increased variability.
In many situations the combination of climate change and other pressures is likely to amplify the impacts on ecosystems. In addition, many changes in ecosystems are likely to be associated with disturbances and climatic extremes, including changes in their frequency or ecosystem recovery. In effect this means the adaptation task is likely to be more complicated in the very places and at the very times where ecosystem-dependent livelihoods are under threat.
Ecosystems pressures and trade-offs
The discussion papers all highlight that ecosystems provide many different utilitarian values. Some like carbon storage are global benefits and traditionally under-valued, others provide local jobs and income, and still others provide subsistence or enhance standards of living of some of the poorest people on the planet. It is therefore quite likely that adaptation to climate change by people in different sectors will create trade-offs between different benefits and place additional pressures on ecosystems. For example, expansion or intensification of agriculture, grazing, logging and fishing, and greater efforts to secure water resources for downstream agriculture, industry and urban users. While win-wins can be envisaged, the deep reality of the trade-offs is enormous. The challenge involved in securing and enhancing the delivery of multiple services and ensuring the conservation of ecosystems themselves is massive. If we are indeed to give species and ecosystems their best chance of adapting to climate change and maintaining the flows of at least some ecosystem services, it may be necessary to plan to reduce the demands on ecosystems from people in all sectors including ecosystem-dependent communities.
Furthermore, while adaptive approaches are often promoted, and management must surely respond to observed changes, a wait-and-see or minimalist approach to adaptation could very readily lead to amplification of the stresses on ecosystems and the people dependent on them, a steady erosion of the adaptive capacity or resilience of both, and inevitable multifaceted crises. Early adaptation, with planned and staged reduction in demands from all sectors, will not prevent losses occurring but it has the potential to reduce some of the feedbacks that might otherwise accelerate losses to species, ecosystems, the services they provide and the communities dependent on them around the world.