What would a world without reefs look like?

Written By Danielle Moloney 


Coral reefs serve a critical role in maintaining the status quo of the Earth, including sustaining a livable environment. Recent headlines highlighting the crisis of mass coral bleaching and subsequent coral mortality beg the question: what would happen to the planet and humanity in the total absence of reefs?

Why are reefs so important?

Although coral reefs may seem far afield for many people, their everyday impact on the environment and human life is nearly incomprehensible. From an environmental perspective, coral reef ecosystems support 25% of marine biodiversity while occupying just 0.1% of the ocean surface (United Nations Environment Programme 2000). Though they live in nutrient poor environments, corals are essential for nutrient recycling and fixation below the waves (Seneca et. al 2010). 

Valued for their ecosystem and economic services, corals present a fragile, unique community characterized by a sensitivity to chronic stressors such as persistent high temperatures (Wilkinson 1992). Over 4.5 billion people around the globe rely on the oceans for their primary source of protein, making them crucial for the support of mankind. Furthermore, while reefs tend to live in shallow waters near coastlines, their structure provides a critical line of defense to coastal communities against the damaging impact of storms. From an economic standpoint, estimates have cited corals as contributing $29.8 billion USD annually to the global economy (International Coral Reef Initiative). The list of benefits provided by reefs goes on, so what would our lives and planet look like without them? Here are a few major changes that we would see in the absence of reefs:

1. A public health crisis 

Given the millions of people who rely on marine protein for a healthy diet, one of the first impacts of reef mortality would be malnutrition and eventually famine in seafood-dependent communities. This impact would be felt almost immediately after the hypothetical loss of all reefs planet-wide. Feeding the rapidly growing global population has already thrown humanity into a crisis; the collapse of reefs would further exacerbate this problem. 

2. Societal instability 

Given the large number of people who are employed indirectly through reef economy, whether it be tourism or fisheries, the social implications of reef collapse would be hard hitting. As millions of people lose their jobs, it is reasonable to believe that social and political instability would follow in the wake of a compromised global economy. The race to attain resources in hopes of retaining the stability of nations would likely cause social chaos. 

3. Extinction and environmental damage 

Reef degradation caused by decreased ocean pH would directly impact much of the marine life in the ocean, especially in sensitive and fragile species that are already on the verge of extinction. As atmospheric carbon levels rise, temperatures also rise, therefore oceans become more acidic, and pH sensitive reefs are struggling to keep up. These ‘diversity hotspots’ are projected to lose biodiversity as temperatures climb and the baseline function of the ecosystems becomes altered (Pratchett et. al 2011). 

Fig. 1 A 2018-2019 heat stress outlook for coral reefs from the National Ocean and Atmospheric Administration (NOAA). NOAA predicts 60% coral bleaching based on anticipated heat stress for the four month period ranging from November 2018 through February 2019. The planet’s largest reef system, the Great Barrier Reef, can be seen listed as ‘Alert Level 1’ off the northeastern coast of Australia. Photo from NOAA, 2018 (https://coralreefwatch.noaa.gov/satellite/analyses_guidance/pacific_cbts_ag_20181106.php)


The effects listed above would vary in intensity from person to person, community to community, and nation to nation as there are varied dependencies on reefs for stability. For example, the nations in Oceania depend on coral reefs more so than other populations who may be further removed from the benefits of reefs (Suatoni 2016). The imminent threat of humanitarian instability looms ever larger as the trend of reef health continues to decline. 

Though the facts regarding a world without reefs can seem bleak, the good news is that coral reefs aren’t going anywhere anytime soon. Many reefs around the globe are still healthy and productive, so while we need not confront a reefless planet as of 2019, it is still worthwhile to consider the immense value that these systems contribute to life on earth and recognize that life as we know it would not be possible in their absence. Although sensitive to environmental change, many reefs have shown resilience in the face of global change, and by adapting to keep up they serve as an indication of the health of their habitat. Scientists and researchers work to solve problems plaguing these ecosystems every day. Many people already strive to live their lives in accordance with a lifestyle that supports healthy coral reefs. Change begins with individual action – educate yourself about how you can prevent us from ever seeing a world without reefs. 

Please see the following links for more information regarding how you can have a positive impact on coral reefs: 

Please contact the author with any questions: dmoloney@fandm.edu 


Béné, C., Barange, M., Subasinghe, R., Pinstrup-Andersen, P., Merino, G., Hemre, G. I., & Williams, M. (2015). Feeding 9 billion by 2050–Putting fish back on the menu. Food Security, 7(2), 261-274.

Pratchett, M. S., Hoey, A. S., Wilson, S. K., Messmer, V., & Graham, N. A. (2011). Changes in 

biodiversity and functioning of reef fish assemblages following coral bleaching and coral 

loss. Diversity, 3(3), 424-452.

Seneca, F. O., Forêt, S., Ball, E. E., Smith-Keune, C., Miller, D. J., & van Oppen, M. J. (2010). 

Patterns of gene expression in a scleractinian coral undergoing natural bleaching. Marine 

Biotechnology, 12(5), 594-604.

Suatoni, Lisa (2016). Coral-dependent Nations Vulnerable to Global Change. National Resource 

Defense Council. 

Wilkinson, C. R. (1992). Coral reefs of the world are facing widespread devastation: can we 

prevent this through sustainable management practices?. K4 Health.

United Nations Environment Programme, Coral Reef Unit (2000). Coral Reefs: Valuable but 

Vulnerable. UNEP. 

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