Stretching towards Antarctica lies a hidden natural oasis – a massive underwater plateau created when continents split more than 100 million years ago.
Straddling the Indian and Southern Oceans, the Kerguelen Plateau is three times the size of Japan. It’s farthest depths are four kilometres below the surface; its islands form one of the most isolated archipelagos on Earth. These include Heard Island and McDonald islands, Australia’s only active surface volcanoes.
Australia and France share a territorial border across the Kerguelen Plateau and work together to study it. The most recent findings, The Kerguelen Plateau: Marine Ecosystems and Fisheries, have been published by the Australian Antarctic Division.
The collaboration has fostered new knowledge of the Kerguelen Plateau as a unique living laboratory – and as the home to one of the world’s most expensive fish.
Tracking the Patagonian toothfish
Volcanic activity pumps vast amounts of minerals such as iron into the water, making the Kerguelen Plateau a biological hotspot.
The plateau hosts populations of Patagonian toothfish, or Dissostichus eleginoides, a predatory fish that lives and feeds near the bottom of the Southern Ocean. The brownish-grey fish grow up to 2 metres long, live for 60 years and can weigh 200kg. The species is often marketed as Chilean seabass.
Australia and France have worked together since the early 2000s to eliminate illegal, unregulated and unreported fishing, to understand the toothfish’s population dynamics and surrounding ecology. As a long-lived top predator with a broad diet, they have a key role in the structure of communities inhabiting the seafloor.
The toothfish is also economically important. Its snow-white flesh is prized as rich, good at carrying flavour and rich in omega-3 fatty acids. Catches command high market prices: prepared fillets have sold for more than A$100 per kg in recent years.
Approved commercial fishing vessels catch Patagonian toothfish around the plateau. Over the past few decades, scientific observers on fishing boats have tagged and released more than 50,000 toothfish at the Australian islands. This, along with annual surveys, biological sampling and data collection, has shed light on the species’ biology and population ecology.
This informs management measures such as total allowable catches and “move on” rules, where vessels must cease fishing in an area once a predetermined weight of non-target fish has been caught.
The nations continue to manage toothfish populations, as well as fish, seabirds and marine mammals that interact with fishing activity.
The shallow banks of the plateau support a spectacular diversity of long-lived sponges, brittle stars, anemones, soft and hard corals and crustaceans. These fragile and slow-growing communities are vulnerable to disturbance. Fishing gear fitted with automated video cameras helps locate and protect sensitive areas, and Australia and France have established marine reserves and managed areas across the plateau.
A unique underwater oasis
The plateau’s islands are incredibly isolated and provide the only breeding and land-based refuge for birds and seals in this part of the Southern Ocean.
Submarine volcanoes, some of them active, surround the islands and are particularly abundant around the younger McDonald Islands.
The plateau cuts across the strong current systems that sweep around the South Pole. This thrusts deep, cold water, enriched with volcanic minerals, to the surface then back to the seafloor. In turn, this powers a food chain stretching from small zooplankton to fish and predators such as Patagonian toothfish, penguins and albatross, and diving marine mammals such as elephant seals and sperm whales.
Carbon and nutrients returned to the seafloor support diverse communities of invertebrate and fish species that could not inhabit this location if not for the plateau.
The orientation and location of the Kerguelen Plateau make it a canary in the coalmine for understanding the southward shift in marine ecology due to climate change. As sea temperatures rise and ocean currents shift, plant and animal species will move south in search of cooler waters.
Recent modelling suggests those species most at risk from climate change in this region are those sedentary or slow-moving invertebrates, such as sea urchins.
Policy backed by science
Work continues to build comprehensive maps of the seafloor, deploy a network of ocean robots to collect physical and biological information, and use French and Australian fishing fleets for research.
The plateau’s waters are in the region overseen by the Commission for the Conservation of Antarctic Marine Living Resources, an international treaty body. French-Australian research is presented to the commission at meetings in Hobart each year to guide management decisions.
The cross-country partnership is a model for international scientific cooperation and fisheries management. In the context of a changing climate, these efforts will provide insight into future impacts on natural systems throughout the Southern Ocean.
International leaders and policymakers gathering in Katowice, Poland, for the 24th annual round of UN climate talks know that they have plenty of work to do.
They are hoping to make progress on the Paris Agreement Work Programme, otherwise known as the Paris Rulebook – the guidelines needed to guide implementation of the Paris Agreement. That agreement was struck three years ago, but it is still not clear how the treaty’s goals to curb global warming will actually be achieved.
This requires all countries not only to slash global greenhouse emissions, but also to help the world adapt to the impacts of climate change. The agreement requires countries to develop national climate plans, to report back on their progress, and to ramp up their efforts in the coming years.
The ‘what’ and the ‘how’
Whereas the Paris Agreement talks about what needs to be done, the Paris Rulebook to be agreed at Katowice is about how nations can set about achieving it. Unlike the previous, more prescriptive Kyoto Protocol, the Paris Agreement allows countries to choose their own approach to climate change. But it is important that actions taken by countries are done within an agreed, transparent framework of rules.
Rules need to be agreed about nations’ emissions targets, climate finance (including climate aid for developing countries), transparency, capacity building and carbon trading. Bringing all of this together is a huge challenge for negotiators. They need to establish a common set of rules applicable to all countries, while also maintaining the crucial principle of “common but differentiated responsibilities and respective capabilities” that underpins the UN climate process.
Already lagging behind
As well as being difficult, the task is also urgent. There is already evidence that countries are struggling to live up to their Paris commitments.
Analysis of the current emissions targets (known as Nationally Determined Contributions) shows that countries need to do more to reach the 2℃ goal. Meeting the 1.5℃ goal will be harder still and will need ambitious and swift action, as recently highlighted by a special report from the Intergovernmental Panel on Climate Change.
Although much of the focus has been on the challenge of bringing emissions targets into line with the Paris goals, our research suggests that climate adaptation efforts are also lagging behind.
Climate adaptation involves managing climate-related risks and deciding on how to manage and prepare for unavoidable impacts, such as increases in intensity and frequency of extreme weather events such as heatwaves and extreme storms, along with slow-onset impacts from sea level rise.
Many countries have developed climate adaptation policies as part of their climate change response. Our recent research analysed 54 of these national adaptation plans to understand how they match up to the intent of the Paris Agreement (as outlined in Article 7 of the Agreement).
We found that most adaptation plans only partially align with the Paris Agreement. Plans were largely focused on the social and economic aspects of adaptation, and were broadly aligned to countries’ existing policy priorities, especially around disaster management and economic development. For developing countries, there was a strong focus on linking adaptation and development.
However, countries are struggling to include environmental considerations into their planning. While the Paris Agreement clearly emphasises the important role that ecosystems play for climate adaptation, most plans are silent on this point.
What’s more, developed countries tended to take a less participatory approach to adaptation planning. Planning in developing countries was hampered by limited access to scientific knowledge but they made more use of local and traditional knowledge. The issue of resourcing and support for developing countries remains a challenge for climate change adaptation.
More work needed
Our results suggest that countries need to build on their existing adaptation plans to meet the ambitions in the Paris Agreement. There are good opportunities to better balance social and economic aspects with environmental and ecological considerations to improve planning.
Many countries, including Australia, have ratified the Paris Agreement, but few are delivering the ambitious action it requires. Besides pursuing deeper cuts to greenhouse emissions, countries need to revisit and update their adaptation strategies. Australia is well positioned to do so, given its economic wealth, its technical abilities, and the extensive climate adaptation research it has already undertaken.
Increasingly, we know what needs to be done to combat climate change. The Katowice summit will hopefully advance an agreement on how countries can do it. But actually doing it on a globally coordinated scale will be the biggest challenge, and there is some way to go to catch up.
Edward Morgan, Research Fellow in Environmental Policy and Planning, Griffith University; Brendan Mackey, Director of the Griffith Climate Change Response Program, Griffith University, and Johanna Nalau, Research Fellow, Climate Adaptation, Griffith University