Reefs Resisting Climate Change

Coral reefs are so much more than beautiful underwater artworks. These multicoloured marvels serve as the bedrock of marine biodiversity, offering crucial support to an estimated 25% of all marine species. Coral reefs also provide food and income for over one billion people around the world, while simultaneously protecting coastlines from the ferocity of storms. Despite their significance, coral reefs are among the most threatened ecosystems on the planet. Climate change-driven temperature rises, coupled with the compound effects of overfishing, pollution and habitat destruction, are orchestrating a widespread decline of coral reef systems worldwide, decimating global reef systems. Yet, amid these challenges, the discovery of naturally resilient reefs, alongside coral restoration initiatives, offers hope for these megadiverse ecosystems…

The Climate Change Threat 101

The 2020 reef documentary Chasing Coral first shone a global spotlight onto the oceans' ghostly white coral graveyards, and educated the masses on the disappearance of coral reefs. Three years later, mass coral bleaching continues to threaten reefs worldwide. This is because rising sea temperatures and ocean acidification causes thermal stress, whereby corals expel the algae which gives them their colour and nutrients. If temperatures return to normal, corals reabsorb the algae, however, if prolonged, the coral skeleton, unable to photosynthesize, will weaken and eventually die.

Local Stressors

Aside from the ever-looming threat of climate change, corals must also battle against an onslaught of local stressors. The added pressures of human activities - like overfishing, pollution and habitat destruction - make it harder for reefs to recover from coral bleaching events. This is where both local and global action is key - particularly with the creation of Marine Protected Areas (MPAs). While MPAs can't protect corals from the sun's rays, they can help protect reefs from being attacked at all angles by providing a marine refuge.

Marine Protected Areas (MPAs)

MPAs have some of the healthiest reefs in the ocean. When managed properly, these underwater national parks can help conserve and restore biodiversity, enabling corals to build ecological resilience. Take the issue of overfishing. A 2023 study in the Sabang Islands, Indonesia, found that surgeonfish support coral resilience by reducing algae cover, thereby giving corals room to 'breathe' and reoccupy. The takeaway: healthy fish populations equate to thriving coral reefs.

Palau: A Leader in Marine Conservation

Palau, a remote tropical archipelago in the western Pacific, is a global trailblazer in ocean conservation. For starters, Palau is the only nation on Earth to protect 80% of its marine environment, making Palau Island Marine Sanctuary one of only five large-scale marine protected areas in the world. This island nation is also tackling the issue of sustainable tourism with the Palau Pledge. Another world-first, travellers must pay a green fee on entering Palau and sign a passport pledge to act environmentally responsible - both educating visitors on their impact on the local environment and safeguarding their reefs.

Corals Resisting Climate Change

While MPAs can protect reefs from local stressors, there's still the effects of climate change to contend with. However, some coral species are adapting. In two 2011 and 2012 studies, ocean researchers found that corals in the lagoons in Palau, which are, on average, two degrees warmer than the open ocean, were able to evolve to withstand higher temperatures.

A further 2022 study investigated the abilities Hawaiian of corals - specifically rice, finger and lobe coral - to acclimatize to a two-degree temperature rise over a period of 22 months. The study found that both lobe and finger coral had a remarkably high survival rate (56 percent and 71 percent respectively, while rice coral had a 46 percent survival rate). As essential reef builders in the Pacific and Indian Oceans, these climate-resistant corals are providing a beacon of hope for global reef systems. However, corals can only take so much extreme heat, meaning curbing carbon dioxide emissions is key.

Restoring Coral Reefs

The sheer number of stresses facing coral means it's unlikely these colourful reef-builders will survive without intervention. Coral restoration initiatives can take on many forms, from educating people on how to reduce their impact on coral reefs to directly addressing climate change. Globally, coral nurseries are proving to be one of the most successful initiatives so far. These nurseries grow healthy, young corals which are then replanted back onto reefs.

Resorts across the world are also rising to the challenge of protecting the world's oceans, from working with local communities to reducing energy use and actively restoring reefs. At the Jean-Michel Cousteau Resort in Fiji, guests can help conduct reef checks or plant at the coral farm. The same goes for COMO Maalifushi in the Maldives, which runs a coral propagation program where broken, but still living, coral fragments are collected and attached to frames planted on the seabed. While much more needs to be done to reduce global warming, both at a global and local level, there is hope for the world's reefs in tomorrow's oceans.