Anthropogenic climate change is driving Antarctica to a point of no return. This is already affecting most earth systems and will have serious implications for humanity and biodiversity. This conclusion was reached by the virtual expert working group of the Polar Institute at the Woodrow Wilson Science Center and the Pew Charitable Trusts, which included leading scientists – specialists in Antarctica from various scientific fields.
The group presented its findings in the report “Climate Change and the Resilience of the Southern Ocean, or Polar Prospects,” issued for the annual meeting of the Antarctic Treaty Consultative Parties, which is being held in France from 14 to 24 June 2021.
Antarctica, scientists write, plays a central role in regulating the world’s climate system. Rapid sea level rise due to melting Antarctica will occur if the Paris Agreement targets (no more than 2 ° C warming in the 21st century) are exceeded. Then, by 2060, the world will come to a tipping point – a warming of 3 ° C, and no amount of human effort will be able to prevent a rise in sea level by 17 to 21 cm just due to the melting of the Antarctic ice by 2100.
The Expert Working Group notes that climate-oriented actions can enhance Antarctic resilience through climate-oriented actions, including the establishment of marine protected areas around Antarctica and the integration of climate change issues to protect humankind from the catastrophic effects of Antarctic ice melt.
The Southern Ocean plays the role of a distribution center for the World Ocean: with the participation of its cold waters, the thermal regime is regulated, the salinity is influenced by the convergence of giant fresh icebergs, and the extraordinary biodiversity provides a significant part of the nutrients for all living things. But in recent years, its waters, both on the surface and at great depths, have warmed faster than the world average. The Southern Ocean has absorbed a disproportionately large amount of anthropogenic carbon dioxide from all captured by the World Ocean – about 40%. The consequence of this is fundamental shifts in ocean life, which will cause physical, biological and socio-economic consequences of a global scale.
Five key processes in the Southern Ocean are approaching the point of no return – and if they are not stopped, severe global consequences are inevitable:
1. Ocean temperature rise. Warm waters around Antarctica are causing glaciers to retreat and melting ice shelves. These changes could cause instability of the ice sheet and the convergence of ice into the ocean, which will lead to their melting and irreversible multimeter rise in global sea level with devastating consequences for coastal regions around the world – threatening the existence of 1 billion people.
2. Degradation of the ice cover. Changes in the area, seasonality and thickness of sea ice lead to the loss of critical habitats and also threaten biodiversity. This affects the productivity and access of fishing vessels to resources in a changing ecosystem.
3. Changes in ocean chemistry. When the ocean absorbs more carbon dioxide from the atmosphere, its acidity rises. This can have serious consequences for the entire ecosystem, disrupt food webs and potentially affect commercial species.
4. Changes in the region’s capacity to absorb carbon. Warming reduces the efficiency of the Southern Ocean biosystem in exchanging carbon between the atmosphere, plant and animal populations, and surface and deep water. Changes in this process – one of the most important ecosystem processes on Earth – have irreversible consequences for the health of the oceans.
5. Shifts in the dynamics of ecosystems and species. Climate change leads to the loss of biodiversity, changes in biological processes, shifts in the geographical distribution of species and changes in the dynamics of food webs regionally and then globally. For example, this could already lead to the southward migration of krill, which plays a key role in the Antarctic food chain. Changes in fish and krill populations affect other species, including seabirds, penguins, seals and a variety of whales. The cumulative consequences of all of these processes are largely unknown.
Avoiding worst-case climate impact scenarios in Antarctica requires immediate and significant reductions in greenhouse gas emissions across all sectors of the economy and countries. Greater focus on climate issues is required on the part of organizations responsible for the management and conservation of marine life in the region, such as the Convention for the Conservation of Antarctic Marine Living Resources (CCAMLR). Although CCAMLR has recognized climate change as one of the greatest challenges facing the Southern Ocean since 2009, its involvement in joint management decisions is still limited. The report notes that the proposed work program
Antarctica is experiencing an unusually cold start to winter, cold which is threatening to break the icy continent’s lowest temperature ever recorded–the -89.6C (-129.3F) registered at Vostok Station on July 21, 1983.
‘Spare a thought for the hardy crew who are wintering down in Antarctica,’ reads the opening paragraph of a recent newshub.co.nz article, ‘who are experiencing near-record breaking cold this week of -81.7C (-115F)‘–logged at Japan’s Dome Fuji Station.
Antarctica New Zealand science tech Jamie McGaw, who is camped 2,400km away from Dome Fuji, at Scott Base, says he “can’t even imagine that extreme cold”.
“I mean, the coldest I’ve experienced here, even in wind chill, is the -60Cs and that is pain — that is any bare skin exposed feels like it’s on fire.”