Antarctica nears tipping points – warnings of global impact | Polarjournal
Penguin population structures change as prey, ice conditions and weather patterns change in the Southern Ocean. Photo: Julia Hager

Just a few days ago, Prof. Markus Rex, expedition leader of the historic MOSAiC expedition, made it clear that initial results from the expedition indicate that sea ice in the Arctic may have already passed its tipping point. At almost the same time, an expert group of leading Antarctic scientists published the report “Climate Change and Southern Ocean Resilience”, in which they also warn that numerous tipping points in Antarctica will soon be reached, with global implications for humanity and biodiversity.

Climate change and its impacts in Antarctica are regularly discussed in the two main diplomatic forums, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) and the Antarctic Treaty Consultative Meeting (ATCM), which is currently taking place for the 43rd time in Paris. However, from the point of view of leading scientists, the measures taken so far are not sufficient to increase the resilience of the Southern Ocean. Therefore, at the end of March this year, they discussed further management measures to cope with climate change and the impact of developments in the Southern Ocean – both the consequences of climate change and management measures – on the global climate as well as on human and ecological systems. The virtual meeting was organized by the Wilson Center Polar Institute and The Pew Charitable Trusts.

Regions in the Southern Ocean proposed as marine protected areas. A network of MPAs could allow for the conservation of different areas, each representing unique ecosystems. Light blue – Existing CCAMLR protected areas; dark blue – Current proposals or draft protected areas being negotiated by CCAMLR. Map: CCAMLR from “Climate Change and Southern Ocean Resilience”, Wilson Center Polar Institute.

Andrea Capurro, Visiting Research Fellow at Boston University and lead author of the report says: “Antarctica is reaching critical thresholds and life around the world is in direct line of the cascading effects. Protecting areas that are most at risk due to climate change, like the Antarctic Peninsula, will not only help us revive biodiversity there but will help boost the resilience of far-flung marine ecosystems. It will also enable us to monitor the long-term effects of other human stressors, like fishing. By nurturing its health in this way, we nurture our own. By building its resilience to climate change, we boost our own.”

The report identifies five key interrelated processes in the Southern Ocean that will be affected by climate change and result in far-reaching changes far beyond the Antarctic region. These include:

  • Shifts in sea ice and ice sheet dynamics
  • Increase in ocean temperatures: collapse of ice shelves and global sea level rise
  • changes in the chemical composition of the oceans: increased uptake of carbon dioxide, leading to acidification and possible disruption of food webs
  • Changes in the biological carbon pump: disruptions in regional carbon storage and sequestration through the exchange of carbon between the atmosphere, plants and animals, and the ocean.
  • Ecosystem and fauna and flora disturbance: impacts on species and ecosystem dynamics leading to loss of biodiversity, altered biological processes, shifts in the geographical distribution of species and changes in food web dynamics, both regionally and globally.
Anthropogenic climate change and the accompanying rapid changes in Antarctica will have profound consequences for humanity and ecosystems worldwide. Of particular concern are the signs that point to the imminent reaching of tipping points that could trigger irreversible, rapid and profound changes in Antarctic biogeochemical cycles and their role in regulating global climate. Graphic: Visual Knowledge, www.visualknowledge.design, from “Climate Change and Southern Ocean Resilience,” Wilson Center Polar Institute

Ecosystem scientist Rachel Cavanagh, who participated in the expert working group along with marine biogeographer Susie Grant, both at the British Antarctic Survey, added: “It is imperative that climate-focused actions are built into conservation and management strategies for the Southern Ocean without delay. Discussions at this month’s ATCM precede the 26th UN Climate Change Conference of the Parties (COP26), to be held in November this year, at which addressing the implications of climate change in Antarctica should be a high priority.”

To address these challenges, the expert working group suggested several actions that CCAMLR could take, such as:

  • the expansion of habitat protection through the creation of a network of marine protected areas around Antarctica;
  • the reassessment of current fisheries management in the light of climate change (until now, decisions on fishing quotas have been based on stock assessments);
  • the use of preventive and ecosystem-based management approaches;
  • Adopt a work plan that takes into account the impacts of climate change in all conservation measures.

With this report, the Expert Working Group raises awareness of the high value of research and governance in this vital region. Its goal is for policymakers to use it as a starting point to bring Antarctica and the Southern Ocean to the forefront of negotiations and to make the challenges in this remote region tangible.

Julia Hager, PolarJournal; Source: British Antarctic Survey

Link to report: https://www.wilsoncenter.org/sites/default/files/media/uploads/documents/PolarPerspectives-Report-FINAL_0.pdf

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