Save Reefs to Rescue All Ecosystems an Approach That Tackles the Underlying Causes of Coral-Reef Decline Could Be Applied to Other Habitats, Argue Tiffany H

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COMMENT CLIMATE From Kyoto to ECONOMICS Michael Mann CULTURE A poet’s clarity ENERGY There’s no free campaigning: an advocate- debates Naomi Klein’s Green navigates our rapidly lunch on a finite planet turned-activist reflects p.337 New Deal manifesto p.340 shifting world p.343 —do the maths p.344 THE OCEAN AGENCY/XL CATLIN SEAVIEW SURVEY SEAVIEW CATLIN THE OCEAN AGENCY/XL

A green sea turtle (Chelonia mydas) swims over corals bleached by anthropogenic global heating. Save reefs to rescue all ecosystems An approach that tackles the underlying causes of coral-reef decline could be applied to other habitats, argue Tiffany H. Morrison, Terry P. Hughes and colleagues.

ll the coral reefs in the world could floor, but they support almost 30% of the safeguard reefs: ecologists, conservationists, be gone by 2070 if global heating world’s marine fish species. Their loss has non-governmental organizations, national continues on its current path1,2. Since huge implications for biodiversity and for and regional policymakers, and philanthro- A1998, heatwaves have bleached or killed cor- the roughly 400 million people who depend pists. Such groups must address the causes of als in more than 90% of reefs listed as World on them for work, food and protection from reef ecosystem decline — not just focus on Heritage sites worldwide (including in the waves, storms and floods in more than biodiversity, or on trying to restore a particu- Galapagos Islands, Hawaii and Australia)2 100 countries across Australasia, southeast lar reef or region to some idealized ‘prior state’, (see ‘Under pressure’). In the Great Barrier Asia, the Indo-Pacific, the Middle East, the for instance by establishing marine parks. Reef, the world’s largest reef system, half of Caribbean and the tropical Americas. Policymakers in Australia, say, should try to the corals died in 2016 and 2017 alone3. We think a change in approach is urgently change land use in the 425,000-square-kilo- Coral reefs cover only 0.5% of the ocean needed from the slew of groups striving to metre catchment of the Great Barrier Reef.

COMMENT

Currently, they funnel some US$14 million diabetes, cardiovascular disease and cancer, can convey a misleading message: that the each year into local-scale approaches such as have risen in part because of the dietary and decline of coral reefs is solvable without rapid, coral gardening to restore damaged reefs. lifestyle changes that have accompanied peo- coordinated action on climate change caused Instead, they should replace coal-fired power ple’s increased reliance on imports. (Six years by human activity. with renewable energy sources, develop land- ago, these diseases caused 80% of all deaths; We think that a bolder approach to the based aquaculture (which avoids the release in 2017, they caused 86%6.) governance of coral reefs should be inspired of animal waste and antibiotics into the sea), The decline of reefs, especially in the past in part by ecological theory on synergistic and restore or rehabilitate terrestrial vegeta- five years, has prompted scientists, policy- effects11. tion, wetlands, mangroves and seagrass. All makers, non-governmental organizations of these actions would simultaneously reduce and philanthropists to undertake increasingly MAKE CHANGES ON LAND AND SEA emissions, capture carbon, curb agricultural desperate attempts to Over the past decade, ecologists have found runoff onto coastal reefs and enhance people’s “Done right, save or restore targeted that the response of reefs to any one pressure, livelihoods and food security. Thus, the ben- efforts to save coral species. (The such as overfishing or pollution, is typically efits would extend far beyond the preservation reefs could most recent 2014–17 non-linear. Numerous feedbacks and multi- of coral reefs. protect other global bleaching event ple drivers reinforcing each other can lead to There is enormous interest in coral reefs ecosystems.” was the longest ever new stable states11. For example, agricultural worldwide, and growing concern about the recorded, and caused runoff can promote the growth of algae that pace of their decline. Done right, efforts to save around 70% of the world’s reefs to bleach once compete with corals for space — a problem reefs could protect other ecosystems by safe- or more in consecutive, record-breaking hot that is exacerbated by the overfishing of her- guarding coastal catchment areas and provid- years7.) bivores. Under many pressures, the capacity ing a model for similar approaches that could In Australia, engineers are using a robot of corals to reassemble after disturbances be applied to diverse systems. Indeed, the to disperse coral larvae to degraded sites and might be so reduced that a new stable eco- plight of coral reefs could finally help to push experimenting with underwater fans to cre- system results, often consisting mainly of nations past a societal and political tipping ate cooling, artificial upwellings. In Florida, mats of algae or cyanobacteria. point, where the protection of ecosystems, surviving corals are being transferred from The sustained protection of coral reefs with their multiple services and functions, is degraded reefs to aquaria to rescue them similarly requires making many changes at seen as socially and politically necessary. from disease. In many countries, artificial once: reducing greenhouse-gas emissions, reefs are being built to promote biodiversity, rebuilding fish stocks and improving water HEAT STRESS or corals are being reared in the laboratory or quality. This requires policymakers to work Raised sea temperatures during heatwaves can in underwater ‘nurseries’ and later transferred with a much broader range of social actors, kill sensitive corals or prompt them to expel to reefs. Coral sperm are even being frozen in including commercial and recreational the beneficial microscopic algae (Symbio the hope that populations could be restored fishers, farmers, the tourism industry, min- dinium and related genera) living in their tis- in the future8. ing companies, energy providers, property sues, resulting in mass bleaching. Over one or Such interventions are difficult, expen- developers and individual citizens. two decades, most coral populations depleted sive and labour-intensive. Replanting coral The importance of such broader-scale, by bleaching can recover. But the gap between fragments grown in a nursery costs between synergistic policy interventions to protect consecutive bleachings has shrunk drastically $1 million and $4 million per hectare9. Thus, ecosystems is starting to be recognized in — from an average of 25 years in the 1980s to even without factoring in ongoing mainte- multilateral policy agreements; by major just 6 years since 2010 (ref. 4). nance, restoring 10 km2 of reef would cost environmental non-governmental organi- Already, people in the 22 small-island in the region of $1 billion9. None of these zations and international aid agencies; and nations and territories of the southwest approaches will restore the ecological func- even by some countries. Pacific have increased their reliance on tions of reefs at a meaningful scale. (Indeed, The Ramsar Convention on Wetlands of imported foods, including canned meats given the current levels of human influence International Importance, for example, now and packaged products, in part because of on the environment, restorations to past highlights how the conservation of wetlands depleted fish stocks. Food imports to coun- ecological conditions and past levels of bio- can help to achieve multiple goals. They can tries such as Samoa and Tonga now exceed diversity are no longer possible10.) What’s conserve biodiversity, act as carbon sinks total exports5. What’s more, deaths in the more, small-scale attempts at coral garden- and provide ecosystem services such as pro- Pacific from preventable diseases, such as ing, aquarium breeding and cryopreservation tection against flooding. (In 1971, when the convention was established, it focused much UNDER PRESSURE more on the conservation of species than on Coral reefs listed as World Heritage sites have been increasingly the broader benefits of wetlands.) a ected by regional and global bleaching since 1980. Likewise, non-governmental organizations

Regional bleaching event Global bleaching events are beginning to combine ecological, eco- 30 nomic and social interventions to help sustain ecosystems. For instance, environmental char- 25 ity the Nature Conservancy in Arlington, Vir- ginia, is considering funding the installation 20 By 2017, 27 out of the 29 of sewage-treatment plants and other infra- World Heritage reefs had structure that would improve public health experienced bleaching.

15 as well as prevent sewage from reaching coral INFORMATION SOURCE: SEE SUPPLEMENTARY reefs12. And agricultural research and develop- 10 ment agencies, such as CGIAR in Montpel- lier, France, are supporting integrated national

Cumulative number reefs of 5 policies for agriculture and the environment in Pacific island nations to address the declin- 0 ing supply of reef fish and the altered move- 1978 1981 1984 1987 1990 1993 1996 1999 2002 2005 2008 2011 2014 2017 ment of pelagic stocks due to climate change.

ALEXIS ROSENFELD/GETTY Biologists track corals in nurseries amid renewed bleaching in French Polynesia.

(Historically, agricultural and environmental Also, various nascent and underused meeting in Baku. The index assesses the ministries in most countries have operated in funding schemes could complement con- risk to individual World Heritage sites (29 of silos, or even in opposition13.) ventional, popular ones. These underused which are coral reefs) from extreme climate Meanwhile, the Philippines, Indonesia, schemes include green economic stimuli, events and changes in climate over the next Malaysia, Papua New Guinea, the Solomon such as public–private partnerships to facili- 30 years. Some environmentalists are suggest- Islands and Timor-Leste have formed the tate the development of renewable-energy ing that this type of index could also be used Coral Triangle Initiative on Coral Reefs, Fish- systems16; and ‘debt-for-change’ schemes, to track accountability. Specifically, such tools eries and Food Security. Established formally whereby organizations such as the Nature could compare the vulnerability of a country’s in 2014, this transnational partnership ini- Conservancy help to pay off a country’s World Heritage site with its national policy on tially focused on the conservation of marine debt in exchange for the nation reducing its carbon emissions and its progress on achiev- biodiversity, megafauna and coastal resources. environmental impact. More-controversial ing Paris climate agreement commitments. Since August 2017, the six governments have industrial and philanthropic payments for Conceivably, a World Heritage site at high risk also begun to address the management of ecosystem services and ecosystem insurance in a country reneging on its promises could mangroves, seagrass meadows and tidal schemes, such as the coral reef insurance be classified as ‘in danger’. Such a develop- marshes to help sequester carbon. A similar programme deployed in Mexico in the past ment would represent a radical expansion of initiative called the Global Environmental year17, could also help. UNESCO’s oversight, and would highlight for Facility Pacific Ridge to Reef Programme is Already, key agencies are extending the the first time the responsibilities of individual seeking to promote sustainable energy and responsibility for safeguarding coral reefs nations for protecting World Heritage sites food production, while reducing global green- beyond local reef governments, managers from climate change. house-gas emissions and pollutant runoff into and users. For example, in a major departure coastal waters, in 14 Pacific island nations14. from the past (see Supplementary informa- THE WORLD IS WATCHING So, on many fronts, the approach we tion), the United Nations Educational, Scien- Ultimately, coral reefs will be lost unless endorse is gaining traction. The major chal- tific and Cultural Organization (UNESCO) global carbon emissions are slashed to 45% lenge now is establishing the governance, World Heritage Centre is beginning to focus of 2010 levels by 2030 (ref. 1). Yet a bolder, organizations, mechanisms and funding to on the long-term and distant drivers of reef scaled-up approach to the stewardship of land realize broad, synergistic goals at scale. decline2, not just on the symptoms of reef deg- and sea — focused initially on coral reefs — Conventional governance — for instance, radation. So, too, are the US National Oceanic could itself help society to meet this goal. of fisheries or agriculture — is typically unco- and Atmospheric Administration and the International attempts to address cli- ordinated, competitive and short-sighted15. Great Barrier Reef Marine Park Authority. mate change have repeatedly derailed1. At a We think that catchment-based agencies In July, the latter called for immediate reduc- national level, vested interests, entrenched could better integrate environmental, social tions in global greenhouse-gas emissions and priorities and social inertia are enormous and economic planning. A good example is acknowledged that local actions on water pol- barriers to change. Australia’s lock-in to coal the 86-year-old Tennessee Valley Authority lution and fishing pressure cannot reverse the is a case in point18. But individual countries in the United States. This agency led innova- ongoing decline of reefs. such as Bhutan and Costa Rica, states such tions in education, agriculture and energy That same month, the Climate Vulnerabil- as California and Tasmania, and even certain use in the 1930s to help lift the region out of ity Index (cvi-heritage.org) was presented at cities such as Copenhagen and Canberra are the Great Depression15. the World Heritage Committee’s annual setting powerful examples for the rest of the

COMMENT GARY CRANITCH, QUEENSLAND MUSEUM/GREAT BARRIER REEF FOUNDATION QUEENSLAND MUSEUM/GREAT CRANITCH, GARY

A tethered robot — LarvalBot — disperses coral larvae on 3 hectares of the Great Barrier Reef.

5. Savage, A., McIver, L. & Schubert, L. Clim. Dev. world with mitigation and adaptation ini- centrepiece of many of the protests. https://doi.org/10.1080/17565529.2019.1605 tiatives. California, the world’s fifth-largest We urge scientists, policymakers, non- 284 (2019). economy, has set a target date of 2045 for car- governmental organizations and philan- 6. World Health Organization. Progress on the bon neutrality. In August, the state brokered thropists to tap into this energy and develop Prevention and Control of Noncommunicable Diseases in the Western Pacific region: Country a deal with four leading carmakers to reduce a bold strategy to protect reefs, other eco- Capacity Survey 2017 (WHO, 2018). air pollution, despite strong criticism from systems and people in our warming world. ■ 7. Eakin, C. M., Sweatman, H. P. A. & Brainard, R. E. US President Donald Trump. Coral Reefs 38, 539–545 (2019). 8. National Academies of Sciences, Engineering, Powerful efforts to protect coral reefs Tiffany H. Morrison is professor of and Medicine. A Research Review of Interventions could similarly set an example for the world. environmental governance and Terr y to Increase the Persistence and Resilience of Coral Reefs are revered worldwide. Their loss has P. Hu g h e s is director and professor of Reefs (National Academies Press, 2019). 19 9. Bayraktarov, E. et al. Restor. Ecol. https://doi. even inspired ‘last-chance tourism’ and biology at the Australian Research Council org/10.1111/rec.12977 (2019). what psychologists and others are labelling Centre of Excellence for Coral Reef Studies, 10. Bellwood D. R. et al. Biol. Conserv. 236, 604–615 ‘ecological grief’20. The plight of these charis- Townsville, Australia. W. Neil Adger is (2019). 11. Turner, M. G. et al. Phil. Trans. R. Soc. B (in the press). matic and stunningly beautiful systems, and professor of human geography and Katrina 12. Wear, S. L. BioScience 69, 360–367 (2019). of the people who depend on them, is rapidly Brown is professor of social science at the 13. Rawe, T. et al. Transforming Food Systems Under galvanizing a broad spectrum of support — University of Exeter, UK. Jon Barnett is Climate Change: Local to Global Policy as a Catalyst for Change (CGIAR, 2019). from the United Nations to film stars, youth professor of global environmental change 14. Granit, J. et al. A Conceptual Framework for movements and industry barons. at the University of Melbourne, Australia. Governing and Managing Key Flows in a Source-to- In 2017, the Leonardo DiCaprio Founda- Maria Carmen Lemos is professor of Sea Continuum (GEF, 2017). tion in Beverly Hills, California, began to environment and sustainability at the 15. Morrison, T. H., Lane, M. B. & Hibbard, M. J. Environ. Plan. Manag. 58, 1601–1616 (2015). install a self-funding system of renewable University of Michigan, Ann Arbor, USA. 16. Republic of Fiji. COP23 Talanoa Dialogue energy in coral-reef communities across Dave Huitema, Cindy Huchery, Tomas Submission: ‘Where are We?’ (UN Framework Fiji, in partnership with the Fijian gov- Chaigneau, Rachel Turner, Missaka Convention on Climate Change, 2018). 17. Beck, M. W. et al. Nature Commun. 9, 2186 ernment and others. In 2018, the charity Hettiarachchi. (2018). Bloomberg Philanthropies in New York City e-mail: [email protected] 18. Nyberg, D. & Wright, C. Acad. Manag. Proc. announced that it would provide $86 mil- https://doi.org/10.5465/AMBPP.2019.90 1. Intergovernmental Panel on Climate Change. (2019). lion to help build the resilience of coral-reef Special Report on Global Warming of 1.5 °C (IPCC, 19. Piggott-McKellar, A. E. & McNamara, K. E. and fishing communities in ten countries, 2018). J. Sustain. Tour. 25, 397–415 (2017). including Australia, Fiji, Indonesia and the 2. Heron, S. F. et al. Impacts of Climate Change on 20. Cunsolo, A. & Ellis, N. R. Nature Clim. Change 8, World Heritage Coral Reefs: Update to the First 275–281 (2018). United States. And in May this year, when Global Scientific Assessment (UNESCO World students in more than 1,600 cities across 125 Heritage Centre, 2018). Supplementary information, including a full 3. Hughes, T. P. et al. Nature Clim. Change 9, 40–43 list of signatories and all author affiliations, countries walked out of school to encour- (2019). accompanies this article online (see go.nature. age more climate action, coral reefs were the 4. Hughes, T. P. et al. Science 359, 80–83 (2018). com/2kiuy4n).