Hundreds of millions of people worldwide depend on coral reef ecosystems[1].
Coral reef ecosystems create natural barriers that protect shorelines from storm surge and erosion—defending villages, businesses, and coastal residents[2].
Coral reef ecosystems also support fisheries that provide food [3], jobs, and income for local communities [4,5] as well as tourism and recreation that contribute to jobs, profits, taxes, and foreign income[3].
The recreational and cultural services provided by these ecosystems also benefit local communities and people.
Increasing levels of carbon dioxide in the atmosphere put shallow, warm-water coral reef ecosystems, and the people who depend upon them at risk from two key global environmental stresses:
1) elevated sea surface temperature (that can cause coral bleaching and related mortality), and
2) ocean acidification (OA). Bleaching and OA can compound local reef stresses that will hasten the loss of the ecosystem services provided by reefs (Fig 1).
Structural damage to coral reefs can result in more severe coastal inundation that puts lives and property at risk [6]. These environmental stresses will also decrease coral ecosystem health and productivity [7,8], which in turn could jeopardize nutrition, livelihoods, and local incomes that depend on reef fisheries and could impact reef-related tourism[5].
We acknowledge that coral reef ecosystems are also threatened by other local stressors that include overfishing, destructive fishing, disease, predators, pollution, eutrophication, sedimentation, and episodic de-oxygenation [9]. Nevertheless, we focus on elevated sea surface temperature and OA because these factors are largely beyond the control of coastal communities, managers of marine protected areas, and other management bodies that exist at the country level or smaller [10].
Coral reef countries have four primary options to counter the threats to reefs caused by the emission of CO2 [11]:
1) urge governments of major CO2-emitting nations (many of which are also home to coral reefs) to reduce carbon emissions that cause both climate change and OA,
2) reduce damages to corals caused by local environmental stressors that can make these problems worse, and
3) improve and/or restore associated ecosystems (e.g. mangroves) to a state that could replace lost ecosystem services and thus minimize impacts on people.
Engineering responses, other than green infrastructure and restoration, to counter these global threats have also been proposed [12,13], but they are largely untested. Without these measures, countries dependent on coral reef ecosystems may need to cope with a world with greatly diminished coral reefs–a response that could spur human migration.
Reefs and People at Risk
Increasing levels of carbon dioxide in the atmosphere put shallow, warm-water coral reef ecosystems, and the people who depend upon them at risk from two key global environmental stresses:
1) elevated sea surface temperature (that can cause coral bleaching and related mortality), and
2) ocean acidification.
These global stressors: cannot be avoided by local management, compound local stressors, and hasten the loss of ecosystem services.
Impacts to people will be most grave where
a) human dependence on coral reef ecosystems is high,
b) sea surface temperature reaches critical levels soonest, and
c) ocean acidification levels are most severe.
Where these elements align, swift action will be needed to protect people’s lives and livelihoods, but such action must be informed by data and science.
An Indicator Approach
Designing policies to offset potential harm to coral reef ecosystems and people requires a better understanding of where CO2-related global environmental stresses could cause the most severe impacts.
Mapping indicators has been proposed as a way of combining natural and social science data to identify policy actions even when the needed science is relatively nascent.
To identify where people are at risk and where more science is needed, we map indicators of biological, physical and social science factors to understand how human dependence on coral reef ecosystems will be affected by globally-driven threats to corals expected in a high-CO2 world. Western Mexico, Micronesia, Indonesia and parts of Australia have high human dependence and will likely face severe combined threats.
As a region, Southeast Asia is particularly at risk. Many of the countries most dependent upon coral reef ecosystems are places for which we have the least robust data on ocean acidification.
These areas require new data and interdisciplinary scientific research to help coral reef-dependent human communities better prepare for a high CO2 world.
Maps Website
Cool website with all this graphically:
https://grid-arendal.maps.arcgis.com/apps/Cascade/index.html?appid=2f440e93fefa4cce8e660c259bd23b50
Citation
Pendleton L, Comte A, Langdon C, Ekstrom JA, Cooley SR, Suatoni L, et al. (2016) Coral Reefs and People in a High-CO2 World: Where Can Science Make a Difference to People? PLoS ONE 11(11): e0164699. doi:10.1371/journal.pone.0164699
Editor: Stefano Goffredo, University of Bologna, ITALY
Pendleton L, Comte A, Langdon C, Ekstrom JA, Cooley SR, et al. (2016)
Coral Reefs and People in a High-CO2 World: Where Can Science Make a Difference to People?
PLOS ONE 11(11): e0164699. doi: 10.1371/journal.pone.0164699
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0164699
You must be logged in to post a comment.