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Reviewing Climate Change Impacts on Ecosystem Services

By Rebecca Runting

What is the state of our understanding of the connection between climate change and ecosystem-service assessment?

Most of us worry about climate change in one way or another, but not many of us explicitly consider its impact on ecosystem services. Maybe that’s because ecosystem services themselves are often taken for granted or undervalued. Climate change threatens the provision of many vital ecosystem services, so it’s important we start taking this into account.

Integrating climate change into assessments of ecosystem services is vital if we are to avoid poor management decisions. For example, coastal land-use zoning that ignores the effects of sea-level rise could lead to a long-term decline in ecosystem services (such as flood protection provided by coastal wetlands).

To add to the challenge, climate change doesn’t impact ecosystem services in isolation – it interacts with other local or global stresses on the environment. Land-use change, population growth and pollution, for example, all create their own stresses and will interact with the impacts of climate change. For instance, a logged forest could become more susceptible to erosion if climate change leads to increases in the intensity of rainfall.

So, what is the state of our understanding of the connection between climate change and ecosystem-service assessment? We did a review of the scientific literature to see if we could identify important gaps. There are many studies of individual cases of climate-change impacts on ecosystem services, but our review provides the first quantitative synthesis on this topic. Here is what we found:

  • A regional bias: First up, most of the papers that were identified in our review came from the USA or Europe, so there is a clear need for more studies beyond these regions, particularly in South America, Asia and Oceania. This is particularly important as these regions generally have a lower capacity to adapt to the impacts of climate change.
  • Mostly negative, some positive impacts: While climate change usually has a negative impact on ecosystem services, the news isn’t all bad as 59% of the analyses showed negative impacts, 24% mixed, 13% positive and 4% neutral. For instance, as temperature and the concentration of carbon dioxide increases, carbon storage is increasing in some places, especially higher latitudes.
  • Expert bias: We found that using (only) expert opinions to determine the impact of climate change can overestimate the negative impacts on ecosystem services. Almost all studies that used expert opinion to determine the impact of climate change produced negative results (94% negative, 5% mixed, 2% neutral). In contrast, only 47% of studies using computational models, or experiments in the laboratory or field, found negative results. The overestimation of negative results produced by expert opinion could be explained by “accessibility bias” – the knowledge that the impacts of climate change are generally negative can disproportionately influence the judgment of the experts (even in cases where the impacts may be positive). This suggests that we should make more use of techniques that minimise bias and corroborate the information provided by experts.
  • Interactions exacerbate negatives: Climate change interacts with other stressors on the environment, such as land use change. Where a stressor in addition to climate change was included, 62% of analyses were negative. Therefore, it is important that we do not consider climate change in isolation when making management decisions.
  • Uneven attention to uncertainty: Some degree of uncertainty was usually incorporated in the assessments (71%), but this was usually surrounding the magnitude of climate change and other drivers, with very little attention given to the uncertainties associated with how ecosystem services are modelled or the mechanisms by which the services were impacted by climate change. Relatively few studies (29%) integrated any kind of decision-making (management actions, policies or other interventions), and even fewer studies aimed to make decisions that were robust to uncertainty.

These results tell us that if management or policy decisions are to ensure the continued provision of ecosystem services, then an integrated approach is needed. Such an approach must include multiple threatening processes and account for multiple sources of uncertainty. This is definitely not an easy undertaking, but ignoring these complications could misrepresent the true impacts of climate change, and result in poor outcomes for climate adaptation decisions.

Rebecca Runting is a member of the ARC Centre of Excellence for Environmental Decisions (CEED) based at The University of Queensland.