Climate change leads to legal uncertainties in the marine area

In the Indo-Pacific, reef islands and reefs naturally expand and contract due to complex biological and physical processes that are still not fully understood. It is currently being increasingly disrupted by climate change, which creates additional uncertainty for small island states and legal offshore areas.

Global distribution of coral reefs (red dots). Image Credit: Millennium Coral Reef Mapping Project/World Atlas of Coral Reefs.

Fortunately, extensive research into the behavior of reef islands, as well as new techniques and methods, may clarify some of the skepticism and support the assertions.

Scientists from Sydney University I have found that as sea levels rise and ocean acidity harms the integrity of coral reefs, atolls and reefs – which are already nebulous and open to interpretation due to their changing nature – will be subject to further twisting.

It is a perfect storm that brings instability and uncertainty to limits that are difficult to define with great precision.

Dr Thomas Fellowes, study lead author and Postdoctoral Research Assistant, School of Earth Sciences, University of Sydney

Dr. Thomas Fellowes adds, “There are geopolitical consequences, too. Reef islands are the legal basis for many large marine areas. Hence, the climate disruptions we are already seeing — and will see in the coming decades — could have a major impact not only on small island states, but on hotly contested border disputes in places like the South China Sea.. “

This treaty, which has been almost universally accepted and signed by 167 countries, regulates everything from territorial waters, up to 12 nautical miles from shore or the low-water line of reefs, to exclusive economic zones, extending up to 200 nautical miles. It codifies regulations governing freedom of navigation and enables countries to use, protect and manage resources in adjacent waters.

For atolls, the outer “low water line” of the reef is used as a legal baseline for the establishment of offshore areas. The potential loss of marine areas due to changes in coral baselines from climate change is a serious concern for countries like Kiribati, as well as for larger nations like Australia, that depend on coral reefs and islands to maintain their claims.

Frances Angadi, PhD student, University of Sydney Law School

Francis Angadi says,But there is still no clear agreement on whether changes to the structural integrity of reef islands due to climate will lead to legal weaknesses. They may not, which is what many Pacific Island nations believe. What is clear is that there is a need for a more detailed understanding of the behavior of reef islands, along with a rethinking of legal rules.“.

Coral reefs are endangered, and thrive only within a specific range of biophysical, oceanic and climatic conditions. But changes in sedimentation due to climate change may support the atolls and reinforce some marine claims. It’s not entirely clear that there will only be losers.

Dr Thomas Fellowes, study lead author and Postdoctoral Research Assistant, School of Earth Sciences, University of Sydney

Scientists claim that determining reef baselines using geographic coordinates, such as GPS, or remote sensing techniques, such as satellite bathymetry, is one way to support current claims.

Another way is to better understand how climate change will affect the island’s ability to support human habitation or economic life, because doing so is another approach to demonstrating that a claim is legitimate under the terms of the treaty.

However, for these strategies to be effective, more data on each reef island system is needed to more accurately determine the true extent of claims already made, assess how resilient these claims are to date, and understand how aspects of climate change may affect them in the future. .

The four ways climate change is affecting coral reef systems and marine boundaries are rising sea levels, rising ocean temperatures, ocean acidification, and increasing storms.

Each influences the intricately linked biophysical processes that allow corals and islands to form, regress, and maintain their overall structural integrity.

For example, warmer temperatures cause a symbiosis of algae in corals and other invertebrates (such as giant clams) to expel their hosts, causing coral bleaching, which, if enough coral organisms die, can cause reefs to collapse. In the following decades, this may cause the outer low-water line of the reef to recede, weakening the basis of marine claim.

Ocean acidification is hampering coral reef formation because the oceans are absorbing increasing amounts of carbon dioxide. Acroporaa small polyp abundant in tropical reefs, and other types of reef-building begin to alter their skeletons so that they are less dependent on carbonate minerals, compromising the stability of the entire reef.

Reefs become corals, barriers, or reefs as they grow and spread. The most common types of coral reefs are those that extend seaward from the shore and create boundaries along adjacent beaches and islands. The reef achieves this at a longer distance, a lake of much deep water that separates it from the land. An atoll develops when a volcanic island submerges below the surface and the coral reefs on it continue to expand.

Journal reference:

colleague, TE, and others. (2022) Stability of reef islands and associated legal marine areas in a changing ocean. Environmental Research Letters.