Outlook Currently, the Antarctic environment is still in comparatively good condition. However, the pressures on the continent and the surrounding ocean are increasing. For example, the influence of ocean warming on the melting of ice shelves and the coastal margins of the ice sheet is accelerating, human presence in the region is increasing, and extraction of marine resources is intensifying. Most importantly, climate change processes are now underway that are likely to alter the physical Antarctic environment over the next decades to centuries, and are likely to become irreversible without policy interventions and technological advances. These changes will affect ecosystems and species populations. Organisms must adapt or will disappear. The candidates most likely to vanish are those, such as emperor penguins, that have adapted to narrow environmental limits, and species that grow and develop slowly, or have limited capacity to disperse. Species more adapted to warmer conditions and historically not found in the Southern Ocean are moving south, and may displace subantarctic and Antarctic species through competition for food or breeding habitat. Climate change poses the most serious threat to Antarctic ecosystems. It requires an international effort to counteract its impacts and substantial financial investments to implement global strategies. The Antarctic Treaty System regulates human activities in Antarctica. Several organisations guide and provide advice on activities in Antarctica and the Southern Ocean. One of these is the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), which seeks to conserve Antarctic marine living resources, including through the management of fishing activities in the Southern Ocean. Various international agreements are also in place, such as the Agreement on the Conservation of Albatrosses and Petrels, which sets guidelines for seabird-safe fishing practices. Various efforts are underway to mitigate the impacts of other human-induced pressures. In Antarctica, the Antarctic Treaty parties recently adopted recommendations to reduce plastic pollution in Antarctica and the Southern Ocean (ATS 2021). The great southern region – Antarctica and the Southern Ocean – is unique in the manner it has been managed through the Antarctic Treaty System. Given the new challenges Antarctica now faces – climate change, and increasing and diversifying human activities – Australia and other treaty nations are continuing to develop new regulatory instruments to ensure the continued protection of the Antarctic region and peaceful collaboration among nations. Impacts Changes are occurring in the climate and weather patterns of Antarctica, as well as in the physical and chemical properties of the Southern Ocean (WMO 2018, IPCC in press-a). Many climatic processes that are changing the Antarctic environment appear to be well underway and are likely to persist for decades or more. Although the physical basis of processes driving the changes is well understood, the precise details of the magnitude and rate of change, and the interactions of change processes across the physical and biological environment are the subject of ongoing investigation (Pecl et al. 2017, IPCC in press-b). The impacts of these changes include altered patterns of temperature, wind and precipitation across the Southern Hemisphere; the increasing contribution of Antarctica to global sea level rise; and effects on the global oceans of changes in the state of the Southern Ocean. Impacts on ecosystems Increasing uptake of carbon dioxide (CO2) into the ocean is causing ocean acidification that is likely to have severe biological impacts within decades. The impacts on the structure and function of marine ecosystems could be dramatic (Feely et al. 2004, Doney et al. 2009, Hutchins et al. 2009, Orr et al. 2009, Dupont et al. 2010, Ericson et al. 2010, Hancock et al. 2020, IPCC in press-a). Such changes would have profound effects on ecosystem services, including the productivity of fisheries, and the ability of the Southern Ocean to absorb and store greenhouse gases. These changes are most pronounced in the Southern Ocean because of the naturally low levels of calcium carbonate (CaCO3) and the greater solubility of CO2in cold water (Figuerola et al. 2021). Impacts on krill and fish stocks The demand for krill oil tablets as a dietary supplement and for fishmeal is currently driving an increase in krill catches (Cavanagh et al. 2021), although krill is rarely consumed directly by humans (Nicol & Foster 2016). Furthermore, the value of toothfish has increased over recent years, which could increase the incentive for illegal, unreported and unregulated fishing. The ecosystem consequences of krill fishing continuously operating at the catch levels set by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) are unknown, but these catch levels currently appear to be sustainable and consistent with the maintenance of krill-dependent predators. However, there is a long-term trend for the fishery to concentrate catches in a few small areas, which may lead to localised depletion and impacts on krill-dependent predators (Watters et al. 2020). CCAMLR has adopted conservation measures that seek to spread krill catches over a wider area. However, a more comprehensive management regime is required to better ensure that the needs of predator species are taken into account. The impact of environmental changes such as ocean acidification on krill populations (Kawaguchi et al. 2009) will also have to be considered when setting catch limits for Southern Ocean fisheries. Impacts on global food production The flow-on effects of altered climate patterns in the Antarctic and Southern Ocean region include changing precipitation patterns in the mid-latitudes of the Southern Hemisphere, with consequences for the resilience of food production and ecosystems (IPCC 2013). The impact of climate change on food production is already becoming apparent and varies regionally. Whereas crop yields have generally increased in South America, the impact has been negative in other areas. For example, in Australia, the production of wheat decreased by around 9% per year from 1974 to 2013 (Ray et al. 2019). Impacts on aesthetic and wilderness values The Protocol on Environmental Protection to the Antarctic Treaty (the Madrid Protocol), adopted in 1991, came into force in 1998. Article 3 of the protocol declares the ‘protection of the Antarctic environment and dependent and associated ecosystems and the intrinsic value of Antarctica, including its wilderness and aesthetic value ... shall be fundamental considerations in the planning and conduct of all activities in the Antarctic Treaty area’. Under Annex V of the protocol, some areas are designated Antarctic Specially Protected Areas to manage and ‘protect outstanding environmental, scientific, historic, aesthetic or wilderness values’ (Secretariat of the Antarctic Treaty 2021). Increasing human activities and expansion of the areas accessed by humans may put aesthetic and wilderness values at risk. Issues yet to be resolved are the absence of assessment methods and lack of an agreed definition of these values (Summerson & Bishop 2012, Leihy et al. 2020). Impacts on human health and wellbeing The Antarctic region is widely regarded as being of special significance to society because of its central role in the climate system, its importance in oceanic food production, and its wilderness and aesthetic values. Although humans derive various benefits from Antarctica and the Southern Ocean, the climate and ecosystem services they provide are still largely underappreciated. A recognition of the values, the manner in which they are linked and the feedback mechanisms at play may improve future management of the region (Bax et al. 2021, Cavanagh et al. 2021). Assessment Social wellbeing related to Antarctica 2021 Adequate confidence The environment of Antarctica is changing, and this will affect global climate and marine systems, with flow-on effects to human wellbeing. Legend How was this assessment made Share on Twitter Share on Facebook Share on Linkedin Share this link Assessment Health of the planet 2021 Adequate confidence The environment of Antarctica is changing, and there are increasing pressures on the ecosystem from variability and trends in weather and climate patterns, and the state of the ocean. Assessment Positive environmental stewardship and international cooperation 2021 Adequate confidence Nations continue to work cooperatively to protect the Antarctic environment. Assessment Protection of key species 2021 Adequate confidence There are encouraging signs that some key species that have been under threat are recovering. However, the populations of some species are still decreasing. Assessment Ecosystem services 2021 Adequate confidence Benefits humans derive from Antarctic ecosystems include food provision, carbon capture, nutrient cycling, research, aesthetic experiences, tourism and recreation.