The 2050 Challenge to a Sustainable Sea

Written by Noelle Helder

The ocean is in trouble – but it’s not (yet) too late

Scientists have laid out an ambitious plan to restore marine habitats in three decades – a plan that would help marine life achieve a sustainable future. If decisive action is taken now, we may be able to prevent irreversible damage to our ocean. 

The ocean is a significant life-supporting environment, hosting high levels of biodiversity, regulating the climate, and sustaining vibrant cultures and economies. To meet the demands of a growing human population, we are increasingly dependent on the ocean. From fisheries to protecting coastlines from storms, the ocean supports our livelihoods to the tune of $1.5 trillion USD (2010), a value projected to double by 2030 (The Ocean Economy 2030). Ocean-based solutions to global challenges are expected to become even more important over time as a source of food, clean water, and alternative energies.

However, many marine species, habitats, and even entire ecosystems have faced disastrous declines under our watch. Industrial whaling historically drove large mammal populations to the brink of collapse, while pollution and unregulated fishing have likewise hindered ocean productivity. Coral reefs are prime examples of this degradation, with precipitous declines in coral cover and structure across the globe. Other important ecosystems like mangroves have been transformed from productive habitats to ocean front properties as coastal development continues to expand. 


Yet, according to a new study published in Nature, significant recovery in the ocean could be achieved by 2050 – if (and it’s a big if) we can successfully mitigate major stressors, including climate change. The authors argue that the ocean has proven its ability to recover and replenish when a stressor is removed, citing examples like rebounding fish stocks after World War I and II when fishing was restricted and the return to health of numerous water bodies following a reduction in the use of fertilizers. 

Marine conservation and policy success stories indicate that the ocean, and many of its species, can be resilient. The International Union for Conservation of Nature (IUCN) Red List shows that the proportion of marine species threatened with extinction has decreased from 18% in 2000 to 11.4% in 2019. Many large mammals have shown particularly impressive comebacks. For example, migratory humpback whales in eastern Australia had declined to less than a few hundred individuals in 1968 as a result of commercial whaling. Currently, their numbers have reached over 40,000 individuals.

Fig. 1 Recovery trajectories over time for a sample of marine species from different parts of the world. Source: Duarte et al, 2020 

Stricter regulations have also been put in place to both protect and restore at-risk habitat. Marine Protected Areas (MPAs) are one of the most widely used tools for habitat protection, with just over 7% of the ocean now protected.  This number is expected to continue to grow by up to 8% every year. Further, habitat restoration projects for oyster reefs, kelp forests, mangroves, and coral reefs are now widely practiced (See how restoration projects have expanded over time).

The struggle ahead

However, the road to recovery will be long. The new plan identifies 6 ‘recovery wedges’ that must be implemented across all marine systems in order to be successful. These include protecting species and spaces, harvesting wisely, restoring critical habitat, reducing pollution, and mitigating climate change. None of these pieces are enough to enact global change on their own. Success hinges on a concentrated, timely effort where all wedges of protection are prioritized, using scientifically proven tools that span across regions, borders, governments, and communities. The challenges that have stood in the way of conservation have not gone away – including (but not limited to) a lack of alternative income sources for fishing communities, lack of funding and enforcement for protected areas, and a rapidly changing climate. 

So what does this all mean for coral reefs?  Unfortunately, there are still many challenges ahead. Even if we meet these ambitious objectives by 2050, coral reefs and deep sea habitats are expected to show the most moderate levels of recovery, as more time will be needed to stem off the precipitous declines that they are facing. Factors that influence reef decline, such as overfishing and pollution, are exacerbated by a warming climate. Restoration efforts, while increasing in scale, have had a limited impact so far. Now more than ever, there is a need to develop restoration techniques that restore important ecosystem processes that will promote reef recovery – like placing corals on reefs with more herbivores to limit macroalgae growth, or prioritizing reefs that have a known source of coral larvae. Targeting species that have shown resistance or adaptation to climate change should also be prioritized in order to give reefs a fighting chance. 

The call to action

While providing lots of good news for the potential future of the ocean, this plan should be viewed as a call to action. To achieve these objectives will take a focused and unified global effort that prioritizes the leadership and involvement from local communities and science-backed policy reform. We are all partakers of the ocean and have a role in preserving its future. We need the educators, policy makers, enforcement officers, researchers, fisherwomen and men, and journalists to take up the cause and advocate for change in their communities. We need employees to hold their companies accountable, artists to create visuals that instill a sense of urgency, and entrepreneurs to develop sustainable products.

Most importantly, we need you to act now. 

Read the article here: 

Duarte, C.M., Agusti, S., Barbier, E. et al. Rebuilding marine life. Nature 580, 39–51 (2020).

Additional sources: 

OECD. The Ocean Economy in 2030 (OECD Publishing, 2016).

IUCN. The IUCN Red List of Threatened Species. (accessed 5 April 2020).MPA Atlas. Atlas of Marine Protection. (accessed 5 April 2020).

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