Madrid Protocol 1991: Antarctic Environmental Protection

What the Madrid Protocol requires: a 40-word direct answer

The Madrid Protocol bans mineral resource activity in Antarctica permanently unless a binding replacement regime is later agreed through a supermajority process (earliest review 2048). It mandates environmental impact assessment for every activity, strict zero-discharge marine pollution rules for ships, waste removal from the continent, species protection, and area management. The Polar Code and MARPOL Annex I add mandatory ship design and HFO prohibition layers on top of those obligations.

Six Annexes at a glance

Background: Antarctic Treaty 1959 and the Treaty System

The Antarctic Treaty 1959 is the parent instrument of the Antarctic Treaty System and the diplomatic foundation on which the Madrid Protocol was built. It was signed in Washington on 1 December 1959 by twelve original signatories: Argentina, Australia, Belgium, Chile, France, Japan, New Zealand, Norway, South Africa, the Soviet Union, the United Kingdom and the United States. It entered into force on 23 June 1961 after ratification by all twelve.

The Treaty’s geographic scope is the area south of 60 degrees south latitude, including all ice shelves but excluding the high seas. Article IV is the celebrated claims-freezing provision, which neither recognises nor renounces existing territorial claims while preventing any new claims or enlargement of existing claims during operation. Article V prohibits nuclear explosions and radioactive waste disposal. Article VII establishes inspection rights for observers from any Consultative Party.

Seven states hold Antarctic territorial claims: Argentina, Australia, Chile, France, New Zealand, Norway and the United Kingdom, with the British, Argentine and Chilean claims overlapping on the Antarctic Peninsula. Russia and the United States maintain a basis of claim without asserting a formal territorial claim. Article IV’s claims-freezing has held throughout more than six decades of Treaty operation.

The Antarctic Treaty System has expanded through subordinate instruments: the 1972 Convention for the Conservation of Antarctic Seals (CCAS), the 1980 CCAMLR Convention (in force 1982), the 1988 CRAMRA mineral resources convention (never entered into force), and the 1991 Madrid Protocol (in force 1998). The Antarctic Treaty Consultative Meeting (ATCM) meets annually as the principal decision-making forum, with the Committee for Environmental Protection (CEP) established under the Madrid Protocol as the principal advisory body for environmental matters.

1991 Madrid Protocol: adoption and 1998 entry into force

The Protocol was negotiated through a series of special ATCMs between 1989 and 1991, against the backdrop of the failed 1988 CRAMRA convention and the surge in international environmental policy that also produced the UNFCCC and the Convention on Biological Diversity. The Protocol was adopted in Madrid on 4 October 1991 at the Eleventh Special ATCM, with the Spanish capital lending the instrument its common name.

Entry into force came on 14 January 1998, thirty days after the deposit of the twenty-sixth ratification, as required by Article 23 of the Protocol body. That article conditions entry into force on ratification by all states that were ATCPs as of the adoption date. The seven-year ratification gap reflects the depth of the obligations assumed and the parliamentary processes required in each state.

The Protocol’s structure comprises twenty-seven articles in the body instrument plus an Annex on Arbitration and the six substantive Annexes. The body covers principles, scope, environmental impact assessment in outline, the mining prohibition, the Committee for Environmental Protection, dispute settlement, amendment, and accession. The Annexes contain the operational rules implementing those principles and carry separate entry-into-force dates.

The Protocol applies to all activities in the Antarctic Treaty area: governmental scientific programmes, non-governmental tour operators, fishing vessels operating south of 60 degrees south, and any other activity for which a party has jurisdiction or responsibility. Vessels of non-party flag states are not directly bound, but MARPOL, the Polar Code and CCAMLR together capture most commercial shipping in the area regardless.

Article 2: “natural reserve, devoted to peace and science”

Article 2 commits the parties to the full protection of the Antarctic environment and dependent and associated ecosystems, designating Antarctica as a “natural reserve, devoted to peace and science.” This single sentence anchors the substantive ambition of the entire instrument.

The natural-reserve designation places the burden of justification on any proposed activity to demonstrate consistency with the protection of the Antarctic environment. As an aspirational matter, it establishes Antarctica as the only continent governed under a broad multilateral environmental regime with such an explicit protective purpose.

Article 3 sets out the Environmental Principles: activities must be planned and conducted to limit adverse impacts on the Antarctic environment; must avoid significant adverse effects on air or water quality, atmospheric, terrestrial, glacial or marine environments, distributions of habitat, native-species populations, and areas of historical and wilderness value; must be subject to prior assessment; and must allow for regular monitoring. Article 4 clarifies that the Protocol supplements but does not modify the parent Antarctic Treaty. Article 5 establishes consistency obligations with other ATS components including CCAMLR.

Article 7: mineral resource prohibition and the 2048 review misconception

Article 7 provides the most celebrated prohibition: “Any activity relating to mineral resources, other than scientific research, shall be prohibited.” The prohibition extends to prospecting, exploration and exploitation of metallic minerals, hydrocarbons, coal and any other commercially exploitable mineral resource.

The duration of the prohibition interacts with Article 25. Article 25.5 provides that, after fifty years from entry into force of the Protocol (that is, after 14 January 2048), any Consultative Party may request through the depositary the convening of a review conference. Such a conference can propose modifications by majority of parties present and voting, provided the majority includes three-quarters of the states that are ATCPs at the time. Any modification of Article 7 specifically requires that a binding legal regime on mineral resource activities is already in force, along with a means to enforce the Article 7 prohibition.

The 50-year provision is not an expiry date. It is the earliest date at which a review process can be requested, and any subsequent modification faces both procedural supermajority requirements and the substantive condition that a binding minerals regime already exists. The 2048 “ban expiry” narrative that circulates in popular coverage is factually wrong. The practical effect is a mining prohibition that is unlikely to be modified before 2048 and that, even after 2048, can only be loosened through a demanding multilateral process.

The Article 7 prohibition replaced the failed 1988 CRAMRA convention. Australia and France declined to ratify CRAMRA in 1989, citing environmental risk and the symbolic importance of Antarctic wilderness. The diplomatic shift, supported by the Antarctic and Southern Ocean Coalition (ASOC) and other environmental organisations, redirected the regulatory architecture from a managed-resource model to a comprehensive prohibition.

Annex I: Environmental Impact Assessment (in force 1998)

Annex I establishes the Environmental Impact Assessment regime. It entered into force on 14 January 1998 as part of the original Protocol package.

The Annex establishes a three-tier framework keyed to predicted environmental impact. Article 1 sets out the preliminary-stage obligation that every proposed activity undergoes a preliminary impact assessment. Article 2 establishes the Initial Environmental Evaluation (IEE) for activities likely to have less than minor or transitory impact. Article 3 establishes the Comprehensive Environmental Evaluation (CEE) for activities likely to have more than minor or transitory impact, with extensive content requirements, public-comment circulation through the Antarctic Treaty Secretariat, and CEP review before the activity may proceed.

CEE processes have been invoked for major national-programme activities including the Belgian Princess Elisabeth Antarctica station (first zero-emission Antarctic station, opened 2009), the Indian Bharati station (commissioned 2012), the Korean Jang Bogo station (commissioned 2014), the Chinese Kunlun and Taishan stations, and the United States’ McMurdo Station modernisation programme under the 2020s Antarctic Infrastructure Modernization for Science (AIMS) initiative.

The CEP reviews CEEs and provides advice to the ATCM on Annex I implementation. The review is non-binding but is highly influential. The Australian Antarctic Division (AAD), United States Antarctic Program (USAP), British Antarctic Survey (BAS) and Antarctica New Zealand all maintain well-developed internal EIA procedures keyed to the Annex I framework. Each national programme publishes its CEEs and IEEs through the Antarctic Treaty Secretariat document system.

Annex II: Conservation of Antarctic Fauna and Flora

Annex II was adopted in 1991 and entered into force on 14 January 1998. A substantial revision adopted by Measure 16 (2009) strengthened the non-native species provisions and consolidated earlier amendments; that revision itself entered into force in 2011.

The Annex prohibits the taking of native mammals, birds and plants in the Antarctic Treaty area except under permit. Taking includes killing, injuring, capturing, handling or molesting, and removal of any native species. Specially Protected Species with elevated requirements include the Ross seal (Ommatophoca rossii) and the Antarctic fur seal (Arctocephalus gazella), plus several penguin and seabird species under regional measures.

The non-native species provisions, strengthened by Measure 16 (2009), prohibit the introduction of any species not native to the Treaty area without a permit, prohibit introduction of soil unless treated, and require precautions to prevent unintentional introduction of micro-organisms. These provisions have become increasingly important as climate warming opens new ecological niches and as visitor volumes have grown past 100,000 per season.

National programme implementation includes biosecurity measures at gateway ports (Hobart, Christchurch, Punta Arenas, Ushuaia, Cape Town), clothing and equipment decontamination protocols, and monitoring for non-native introductions. IAATO has integrated parallel biosecurity protocols into its operating standards, addressing seed transfer on boots, ballast water exchange and hull-fouling inspection.

Annex III: Waste Disposal and Waste Management (in force 1998)

Annex III entered into force on 14 January 1998. It addresses both waste minimisation principles and specific operational rules for the Treaty area.

The Annex creates a general obligation to reduce waste generated in the Treaty area to the maximum extent practicable and to remove waste from the Treaty area wherever practicable. Specific prohibitions cover disposal of PCBs, non-sterile soil, polystyrene packing and pesticides (other than those required for scientific or hygienic purposes), among other categories. Open burning of waste is prohibited except for specific limited categories such as paper and cardboard at remote field camps without access to electric incinerators, and then only with appropriate emission control.

Each party must maintain a waste management plan for each station and field activity, covering waste classification, on-site storage, on-site treatment where applicable, and removal from the Treaty area. Annual waste management reports are submitted to the ATCM through the CEP.

The waste-management regime is among the most stringent in the world for any operating environment. McMurdo Station ships all hazardous and non-biodegradable waste back to the United States. The British Halley VI mobile station was designed to leave no permanent infrastructure footprint on the Brunt Ice Shelf. The Belgian Princess Elisabeth station operates as the first zero-emission Antarctic station with renewable energy and on-site waste processing.

Annex IV: Prevention of Marine Pollution (in force 1998)

Annex IV entered into force on 14 January 1998. It applies to all vessels of Antarctic Treaty parties operating in the Treaty area and parallels the MARPOL Convention discharge regime with Antarctic-specific stringency.

Article 3 prohibits discharge into the sea of oil or oily mixture from any vessel of an Antarctic Treaty party, including all fuel oil, lubricating oil, oil sludge and oily bilge water. This is tighter than the MARPOL Annex I general regime, which permits limited discharges meeting specific criteria, by establishing a zero-discharge standard within the Treaty area.

Article 4 prohibits any discharge into the sea of noxious liquid substances and any other chemical or substance in quantities or concentrations harmful to the marine environment.

Article 5 prohibits disposal into the sea of all plastics including synthetic ropes, fishing nets and plastic garbage bags, with tight rules on other garbage categories.

Article 6 prohibits discharge of untreated sewage within 12 nautical miles of land or ice shelves, with broader restrictions on vessels carrying more than ten persons. These thresholds are tighter than those of the MARPOL Annex IV sewage regime.

The Annex is independent but parallel to MARPOL. Vessels of states that are parties to both must comply with the more stringent regime, which in the Antarctic Treaty area is generally Annex IV. The parallel MARPOL Annex V Antarctic Special Area (designated 1992 by MEPC.51(32)) further reinforces the garbage discharge rules under both instruments. Both operate south of 60 degrees south.

Annex V: Area Protection and Management (in force 2002)

Annex V was adopted by Recommendation XVI-10 (1991) as part of the original Protocol package but was the last of the original Annexes to enter into force, becoming effective on 24 May 2002 after the deposit of the necessary ratifications.

The Annex establishes the integrated Antarctic Specially Protected Area (ASPA) and Antarctic Specially Managed Area (ASMA) regime, replacing the earlier overlapping categories of Specially Protected Areas, Sites of Special Scientific Interest, Specially Reserved Areas and Multiple-use Planning Areas.

An ASPA protects outstanding environmental, scientific, historic, aesthetic or wilderness values. Entry requires a permit from an appropriate authority, and each ASPA is governed by an ATCM-adopted management plan reviewed every five years. An ASMA applies where activities risk mutual interference or cumulative environmental impact, requiring planning and coordination through a management plan; entry is permitted but governed.

The current inventory exceeds seventy ASPAs and a smaller number of ASMAs, covering emperor penguin colonies, early exploration huts (Scott’s Discovery Hut at Cape Evans, Shackleton’s Cape Royds Hut, Mawson’s Cape Denison station), ecologically significant marine areas including parts of the Ross Sea and Terra Nova Bay, the dry valleys of Victoria Land, and station-area integrated management zones around McMurdo, Larsemann Hills and Admiralty Bay. Historic Sites and Monuments (HSMs) form a parallel category, with the inventory exceeding ninety HSMs as of 2026 covering early exploration heritage and Cold War scientific milestones.

Annex VI: Liability for Environmental Emergencies (adopted 2005, not yet in force)

Annex VI on Liability Arising from Environmental Emergencies was adopted by Measure 1 (2005) at the Twenty-Eighth ATCM in Stockholm. As of 2025, the Annex has not yet entered into force. It requires approval by all 28 Consultative Parties entitled to attend the Stockholm ATCM. Approximately 13 parties have ratified or accepted it, including Peru (2007), Sweden (2006), Poland (2009), Spain (2008), Finland (2010), Italy (2011), New Zealand (2013), Norway (2013), South Africa (2013), Australia (2014), Netherlands (2014), United Kingdom (2014) and Ecuador (2016), based on ECOLEX treaty database records. Several major ATCPs including the United States, Germany, Russia, France, China, Japan, Argentina and Chile have not yet completed their domestic ratification processes.

The Annex defines an environmental emergency as an accidental event resulting in or imminently threatening significant and harmful impact on the Antarctic environment. Each operator must take preventative measures to reduce the risk of such emergencies; must take prompt and effective response action when an emergency arises; and where an operator fails to respond, is liable for the costs of response action taken by others.

Liability under Annex VI is strict and capped at limits graduated by ship size and activity type, with insurance or other financial security required. The cap structure broadly parallels that of the Bunkers Convention 2001 and other modern environmental liability instruments.

The Annex VI regime, when in force, will provide one of the most stringent environmental liability frameworks in any treaty system, reflecting the high vulnerability of the Antarctic environment and the severely constrained response capacity in a region with seasonal access windows and extreme remoteness.

Antarctic Treaty: 58 contracting parties (29 Consultative + 29 Non-Consultative)

The Antarctic Treaty contracting parties total 58 as of 2025, comprising 29 Consultative Parties (ATCPs) with full decision-making rights at the ATCM and 29 Non-Consultative Parties with observer rights. The United Arab Emirates acceded in December 2024, bringing the non-consultative count to 29. The ATCP count reached 29 when the Czech Republic elevated to consultative status in 2014.

The 29 ATCPs are: the twelve original signatories (Argentina, Australia, Belgium, Chile, France, Japan, New Zealand, Norway, South Africa, Russia/USSR, United Kingdom, United States) plus Brazil, Bulgaria, China, Czech Republic, Ecuador, Finland, Germany, India, Italy, Republic of Korea, Netherlands, Peru, Poland, Spain, Sweden, Ukraine and Uruguay. Poland (1977) was the first non-original state to attain consultative status.

ATCP status under Article IX(2) of the Treaty requires demonstrated substantive scientific interest through establishment of a scientific station or dispatch of a scientific expedition. Decision-making at the ATCM proceeds by consensus under longstanding practice. The consensus requirement has been a strength of the Treaty System and a source of frustration: it has held the CCAMLR Marine Protected Area proposals under Russia and China objection for over a decade, and has contributed to the slow pace of Annex VI ratification completion.

1988 CRAMRA: the precursor that never entered into force

The Convention on the Regulation of Antarctic Mineral Resource Activities (CRAMRA) was adopted on 2 June 1988 at the Wellington ATCM. It would have established a regulated framework for mineral prospecting, exploration and exploitation, with a Commission, a Scientific Committee, an Advisory Committee on the Environment, and detailed environmental assessment and liability provisions.

CRAMRA never entered into force. Australia under the Hawke government and France under the Mitterrand government declined to ratify in 1989. Both governments cited increasing environmental concern about any commercial mineral activity in Antarctica and the symbolic importance of the continent as wilderness. ASOC and the broader environmental NGO community had campaigned strongly against CRAMRA.

The collapse of CRAMRA opened the diplomatic space for the Madrid Protocol negotiations, which redirected the architecture from a managed-resource framework to a comprehensive prohibition. The Article 7 mining ban is the policy successor to CRAMRA’s failed framework and reflects a fundamentally different regulatory philosophy. CRAMRA remains closed and superseded, although its negotiating record informs the structural choices embedded in the Protocol.

CCAMLR Convention 1982: Antarctic marine living resources

The Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) was adopted in Canberra on 20 May 1980 and entered into force on 7 April 1982. CCAMLR has a wider geographic scope than the Antarctic Treaty: it extends to the Antarctic Convergence (broadly following the Polar Front at approximately 50 to 60 degrees south) rather than the strict 60 degrees south of the Treaty area. But it operates within the Antarctic Treaty System as one of its core components.

CCAMLR’s mandate is conservation, where conservation includes rational use, governed by three substantive principles: prevent decrease in harvested populations below stable-recruitment levels; maintain ecological relationships between harvested, dependent and related populations; and prevent irreversible marine ecosystem changes. The CCAMLR Commission meets annually in Hobart, Tasmania, adopting Conservation Measures by consensus across approximately twenty-five Members.

The Commission governs fisheries including toothfish (Dissostichus eleginoides and D. mawsoni), icefish, krill (Euphausia superba) and other species; established the Ross Sea MPA in 2016 (entry into force 1 December 2017); addresses by-catch including seabirds and seals; and governs Vessel Monitoring System (VMS) reporting and observer programmes.

The krill fishery in CCAMLR Area 48 (Atlantic sector, encompassing the Antarctic Peninsula, South Georgia and South Sandwich Islands) is the largest by catch volume in the Treaty area. CCAMLR’s Fishery Report documented a total Area 48 krill catch of approximately 424,203 tonnes in 2023 and approximately 498,350 tonnes in 2024, the latter a historic high since CCAMLR began collecting data in 1973. Norway dominates: Aker Qrill Company’s three vessels alone caught 307,612 tonnes in 2024. China, South Korea, Ukraine and Chile account for most of the remainder. The broader precautionary catch limit is 5.6 million tonnes per season; the practical operating ceiling under Conservation Measure 51-07 is a trigger level of 620,000 tonnes within Subarea 48 pending development of a risk-based catch-allocation system.

CCAMLR’s interaction with the Madrid Protocol is substantial. CCAMLR addresses the marine living resources dimension that the Protocol body and Annexes do not directly regulate, while the Protocol’s Annex II (fauna and flora protection), Annex IV (marine pollution) and Annex V (area protection) operate across the same waters. The two regimes coordinate through a CCAMLR-CEP relationship and annual information exchange.

Antarctic Special Area under MARPOL Annex V (since 1992)

The Antarctic Special Area under MARPOL Annex V was designated by IMO Resolution MEPC.51(32) in 1992. The designation covers the sea area south of 60 degrees south, paralleling the geographic scope of the Antarctic Treaty area.

The Special Area designation imposes the strictest garbage discharge regime under MARPOL Annex V, prohibiting the discharge of all garbage with very narrow exceptions for food waste meeting specific criteria. The regime parallels and reinforces Annex IV of the Madrid Protocol, with MARPOL providing the global ship-source pollution architecture and the Protocol providing the Antarctic-specific layer.

Vessels of MARPOL party flag states in the Antarctic Special Area must comply with Annex V and the parallel Reception Facilities obligation under MARPOL Annex V Regulation 8. Reception facilities for Antarctic-bound vessels concentrate at the gateway ports: Hobart (Australia), Christchurch (New Zealand), Punta Arenas (Chile), Ushuaia (Argentina) and Cape Town (South Africa). Capacity and waste-stream coordination at these ports has been a recurring topic in IMO and ATCM discussions.

Separately, MARPOL Annex I Regulation 43, which entered into force on 1 August 2011, prohibits vessels from carrying or using as fuel any heavy fuel oil in the Antarctic area. The definition covers crude oils with density at 15°C above 900 kg/m³, other oils with density above 900 kg/m³ or kinematic viscosity at 50°C above 180 mm²/s, and bitumen, tar and their emulsions. A 2014 amendment additionally prohibited carriage of HFO in ballast tanks following a fishing vessel sinking in Antarctic waters. The Antarctic HFO ban carries no flag-state exemptions or waivers, unlike the 2024 Arctic HFO ban under Resolution MEPC.327(75) which does contain limited waivers for Arctic coastal state-flagged vessels. The Antarctic ban has been in force for over a decade with no exceptions.

Polar Code 2017: supplementing the Protocol

The International Code for Ships Operating in Polar Waters (Polar Code) entered into force on 1 January 2017 under both SOLAS Chapter XIV (safety provisions, adopted MSC.385(94), November 2014) and the MARPOL Convention (environmental provisions, adopted MEPC.264(68), May 2015). The Polar Code applies to ships operating in Arctic and Antarctic waters.

The Code establishes three ship categories: Category A (designed for operation in at least medium first-year ice with old ice inclusions); Category B (designed for at least thin first-year ice with old ice inclusions); and Category C (designed for open water or ice conditions less severe than A or B). For each category the Code specifies Polar Ship Certificates, Polar Water Operational Manuals (PWOM), ice-class hull and machinery requirements, lifesaving equipment specifications, communications, fire safety, voyage planning requirements and environmental measures.

Part II of the Polar Code addresses environmental protection: Chapter 1 (oil pollution prevention), Chapter 2 (noxious liquid substances control), Chapter 4 (sewage), and Chapter 5 (garbage). Chapter 5 of Part II prohibits all garbage discharge into polar waters, paralleling the MARPOL Annex V Special Area regime and the Madrid Protocol Annex IV. The Polar Code also incorporates the IACS Polar Class structural requirements (PC1 to PC7) and the parallel ice-class systems of major classification societies.

For Antarctic operations the Polar Code complements the Protocol’s Annex IV by adding the ship-design and operational layers that the Protocol itself doesn’t specify: ice-class hull, sewage and garbage management hardware, and STCW-Polar training requirements. It doesn’t replace Annex IV; it supplements it with mandatory IMO-level standards applicable through flag-state and port-state-control enforcement.

IAATO 1991: International Association of Antarctica Tour Operators

The International Association of Antarctica Tour Operators (IAATO) was founded on 2 October 1991 by seven original member companies, two days before the adoption of the Madrid Protocol. IAATO is a voluntary self-regulatory organisation headquartered in Newport, Rhode Island, whose members cover essentially all commercial Antarctic tourism activity.

IAATO’s Operating Procedures and Voluntary Standards include: vessel size limits at landing sites (maximum 100 passengers ashore at any one time per the standard IAATO site guidelines); guide-to-passenger ratios; biosecurity protocols including boot washing, vacuum cleaning and equipment decontamination; wildlife approach distances and behaviour codes; daily and seasonal visit caps at landing sites; and pre-visit, in-Antarctica, and post-visit reporting. Integration with CCAMLR and the Antarctic Treaty Secretariat runs through annual reporting cycles and information papers submitted to the ATCM.

Antarctic tourism set a new record in the 2023-24 austral summer season at 122,072 visitors, according to IAATO’s report to ATCM 46 (ATCM46 IP102 rev.1). This exceeds the pre-pandemic high of approximately 73,991 in 2019-20. Preliminary IAATO estimates for 2024-25 put the figure at approximately 107,270 visitors, with a decrease attributed to one major cruise-only operator suspending operations for that season. Over 98% of Antarctic tourism activity is concentrated on the Antarctic Peninsula, departing primarily from Ushuaia, Argentina and Punta Arenas, Chile.

The IAATO model has been recognised by ATCM and CEP as a contribution to the Protocol’s environmental objectives. The voluntary self-regulation has scaled from approximately 6,500 visitors in 1992-93 to the current six-figure levels. IAATO’s relationship to the Protocol is voluntary, not mandatory: national Antarctic programmes regulate flag-state operators through Madrid Protocol implementing legislation; IAATO coordinates the operators’ practical implementation; and the ATCM provides multilateral oversight.

IACS Polar Class PC1-PC7 system (2008)

The IACS Polar Class system was published in 2008 as IACS Unified Requirements I1 to I3, establishing seven Polar Classes from PC1 (year-round operation in all polar waters) through PC7 (summer/autumn operation in thin first-year ice with old ice inclusions). The system harmonised previously diverse classification-society ice-class notations into a single mutually-recognised framework.

The PC class hierarchy:

• PC1: Year-round operation in all polar waters
• PC2: Year-round operation in moderate multi-year ice conditions
• PC3: Year-round operation in second-year ice that may include multi-year ice inclusions
• PC4: Year-round operation in thick first-year ice that may include old ice inclusions
• PC5: Year-round operation in medium first-year ice that may include old ice inclusions
• PC6: Summer/autumn operation in medium first-year ice that may include old ice inclusions
• PC7: Summer/autumn operation in thin first-year ice that may include old ice inclusions

The IACS Polar Class notation is incorporated by reference into the Polar Code, with the Code’s Categories A, B and C linked to specific minimum PC ratings. For Antarctic operations the predominant classes encountered are PC6 (most expedition cruise vessels on Peninsula and Ross Sea summer itineraries) and PC7 (lighter expedition vessels for marginal-ice-zone operations). National programme icebreakers and research vessels range from PC2 (Russian Antarctic Expedition vessels) to PC4 (British RRS Sir David Attenborough, Korean Araon) to PC3 (Chinese Xue Long 2) and PC5 (South African SA Agulhas II).

Each major classification society maintains the PC notation alongside legacy ice-class systems: DNV (Ice-1A Super, Ice-1A, Ice-1B, Ice-1C and PC series); ABS (Ice Class series including PC); Lloyd’s Register (Ice Class including PC); Bureau Veritas, Korean Register, Class NK, China Classification Society and Russian Maritime Register of Shipping all maintain interoperable PC and legacy ice-class notations.

MARPOL Annex I Regulation 43 and the HFO regime in Antarctic waters

MARPOL Annex I Regulation 43, which entered into force on 1 August 2011, prohibits ships from carrying or using as fuel any heavy fuel oil in the Antarctic area (south of 60 degrees south latitude). The prohibition covers carriage in bulk as cargo, use as fuel, and carriage as ballast. The definition: crude oils with density at 15°C above 900 kg/m³, or other oils with density above 900 kg/m³ or kinematic viscosity at 50°C above 180 mm²/s, or bitumen, tar and their emulsions. The only exemption is for vessels engaged in securing the safety of a ship or conducting a search-and-rescue operation.

This Antarctic HFO ban is distinct from and predates the Arctic HFO ban. Resolution MEPC.327(75), adopted by IMO MEPC at its 75th session in November 2020, prohibits use and carriage of HFO in Arctic waters from 1 July 2024 with phase-out by 1 July 2029. The Arctic ban includes limited waivers for vessels flagged by Arctic coastal states with sovereign Arctic waters. The Antarctic ban carries no equivalent waivers and has been in effect since 2011.

The risk profile motivating both bans is the same: HFO weathers slowly in cold water and remains hazardous to wildlife and marine ecosystems for extended periods, and response capacity in remote polar waters is severely constrained. For Antarctic operations, the practical fuel options for expedition vessels and national programme ships are marine gas oil (MGO) and very low sulphur fuel oil (VLSFO). The global 0.50% sulphur cap under MARPOL Annex VI Regulation 14 further constrains fuel choices, and Regulation 13 NOx tier standards govern engine NOx emissions for the relevant build-date cohorts.

Operator-side investment in fuel-system modification and fuel-quality management has been substantial since 2011. Modern PC-class expedition vessels on Antarctic itineraries routinely carry only MGO or VLSFO. The annual IAATO pre-trip checklists and gateway-port PSC inspections both verify fuel type compliance as a routine element.

Antarctic research stations: McMurdo, Vostok, Concordia, Halley VI, Princess Elisabeth

The Antarctic continent hosts more than seventy permanent and summer-only research stations operated by approximately thirty ATCP national programmes.

McMurdo Station (United States, USAP, Ross Island, since 1956) is the largest Antarctic station, with summer population peaking around 1,000 and winter population around 200. It is the logistics hub for the USAP including Amundsen-Scott South Pole Station. The 2020s Antarctic Infrastructure Modernization for Science (AIMS) programme is delivering a substantial reconstruction.

Vostok Station (Russia, formerly USSR, East Antarctic plateau, since 1957) sits at 3,488 metres elevation near the geomagnetic South Pole. Famous for the deep ice-core programme retrieving climatic records back more than 400,000 years, and for the discovery of Lake Vostok beneath the ice. Vostok holds the documented world cold-temperature record at minus 89.2 degrees Celsius, recorded in 1983.

Concordia Station (France-Italy joint, Dome C plateau, since 2005) operates year-round at 3,233 metres elevation under the Institut polaire français Paul-Émile Victor (IPEV) and the Programma Nazionale di Ricerche in Antartide (PNRA). Concordia hosts the EPICA successor ice-coring programme, atmospheric science, astronomy and human-physiology research relevant to long-duration spaceflight.

Princess Elisabeth Antarctica (Belgium, Dronning Maud Land, since 2009) is the first zero-emission Antarctic station, designed by the International Polar Foundation with wind and solar primary power, energy-efficient construction and on-site waste processing. It operates as a summer-only station with capacity for approximately twenty personnel.

Halley VI Research Station (United Kingdom, BAS, Brunt Ice Shelf, since 2012) is a mobile station designed to be relocated as the floating ice shelf migrates. Halley contributed to the original detection of the Antarctic ozone hole in the 1980s. Halley VI’s design is a benchmark for low-environmental-impact Antarctic infrastructure under the Madrid Protocol EIA framework.

Other notable stations include: German Neumayer III; Japanese Showa; South African SANAE IV; Norwegian Troll; Indian Bharati and Maitri; Chinese Great Wall, Zhongshan, Kunlun and Taishan and the new fifth station at Inexpressible Island; Korean King Sejong and Jang Bogo; Argentine Marambio, Belgrano II and Esperanza; Chilean Bernardo O’Higgins and Frei with associated airfield; and Brazilian Comandante Ferraz.

Personnel, logistics, and environmental footprint

The total Antarctic personnel population peaks at approximately 5,000 individuals in the austral summer (December to February) and falls to approximately 1,200 in the austral winter (June to August) at year-round stations.

The summer peak reflects the active field research season, station resupply by ship and aircraft, construction and maintenance activity, and the rotation of winter-over personnel. The winter resident population maintains year-round operations at the principal stations, conducts long-night astronomical, atmospheric and biomedical research, and provides emergency response capacity.

The personnel logistics impose a substantial environmental footprint that the Madrid Protocol regime is designed to manage: fuel consumption for power, heating and transport (driving the HFO and fuel-quality regime under Annex IV); waste generation and removal (Annex III); biosecurity and non-native species risks at gateway-port and station entry (Annex II); and infrastructure footprint at stations (Annex I CEE process for new construction and major modification). National programmes have invested in renewable-energy integration, waste-stream optimisation and efficiency improvement through the 2010s and 2020s, with Princess Elisabeth as the most ambitious benchmark.

CCAMLR Marine Protected Areas: Ross Sea MPA and pending proposals

The Ross Sea Region Marine Protected Area was established by CCAMLR Conservation Measure 91-05 (2016) and entered into force on 1 December 2017. It is the largest marine protected area on Earth at approximately 1.55 million km², roughly twice the area of France. New Zealand and the United States co-proposed the MPA; final adoption in 2016 required a difficult diplomatic process over more than a decade.

The Ross Sea MPA comprises three zones: a General Protection Zone (GPZ) of approximately 1.12 million km² where commercial fishing is prohibited; a Special Research Zone (SRZ) of approximately 110,000 km² where research-related fishing is permitted under specific protocols; and a Krill Research Zone (KRZ) of approximately 322,000 km² where krill fishing is permitted under research protocols. The MPA has a 35-year initial term, with review at year 35 (2052).

Two further large proposals have been on the CCAMLR negotiating table for more than a decade but have not been adopted. The Weddell Sea MPA proposal, co-led by Germany and the European Union, would cover approximately 2.18 million km² in the Weddell Sea sector. The East Antarctic Representative System of Marine Protected Areas (ERSMPA) proposal, co-led by Australia, the European Union and France, would establish a network covering approximately 950,000 km². A third proposal, Domain 1, co-led by Argentina and Chile, addresses the Peninsula sector where krill fishing and tourism are most concentrated.

Russia and China have blocked both the Weddell Sea and East Antarctic proposals at successive CCAMLR Commissions through objections focused on the scientific basis for specific boundary geometries, precedent for long-term closure of high-seas areas, and protection of fishing interests. Diplomatic efforts have continued without achieving consensus.

National Antarctic programmes: AAD, USAP, BAS, Antarctica New Zealand

National Antarctic programmes are the principal operational vehicles for Madrid Protocol implementation by ATCPs.

The Australian Antarctic Division (AAD), headquartered in Hobart, operates Casey, Davis and Mawson stations on the Antarctic continent and a station on Macquarie Island. The AAD maintains the RSV Nuyina (entered service 2021, PC3 ice-class) and aviation operations through Hobart. The AAD sits within the federal Department of Climate Change, Energy, the Environment and Water.

The United States Antarctic Program (USAP), administered by the National Science Foundation (NSF) Office of Polar Programs, operates McMurdo Station, Amundsen-Scott South Pole Station and Palmer Station on the Peninsula, with logistics support from the United States Coast Guard, United States Air Force LC-130 Hercules ski-equipped aircraft, and contractors including Leidos.

Antarctica New Zealand, headquartered in Christchurch, operates Scott Base on Ross Island adjacent to McMurdo Station and coordinates the Christchurch gateway-port infrastructure. Long-standing NZ-US logistics cooperation allows shared aircraft and some shared logistics between the two programmes.

The British Antarctic Survey (BAS), headquartered in Cambridge, operates Halley VI, Rothera Research Station on the Peninsula, Bird Island and King Edward Point on South Georgia, and Signy on the South Orkney Islands. BAS operates the RRS Sir David Attenborough (commissioned 2021, PC4) and the legacy RRS James Clark Ross. The Alfred Wegener Institute (AWI) (Germany) operates Neumayer III and the icebreaker Polarstern, with Polarstern II planned for service from approximately 2027. The Chinese Polar Research Institute of China (PRIC) operates four continental stations plus the fifth station at Inexpressible Island (under development as of 2026).

Arctic counterpart: AECO and divergent regulatory architecture

The Association of Arctic Expedition Cruise Operators (AECO), founded in 2003 and headquartered in Longyearbyen, Svalbard, is the Arctic counterpart of IAATO. It performs an analogous voluntary self-regulatory function for Arctic expedition cruise operators, with standards keyed to the Svalbard Treaty 1920 regime, Greenland self-government framework, Canadian Arctic federal and indigenous regulatory framework, and Russian Arctic operational regime.

AECO and IAATO coordinate on issues spanning both poles: biosecurity protocols, oil pollution prevention, wildlife approach standards, Polar Code implementation, and gateway-port reception facility coordination. Both organisations have presented joint papers at IMO MEPC and MSC sessions on Polar Code implementation and the HFO bans.

The Arctic regulatory architecture differs fundamentally from the Antarctic. The Arctic is bordered by sovereign states whose Exclusive Economic Zones, continental shelves and internal waters dominate the regulatory geography. The Antarctic is a single integrated multilateral regime with claims-frozen and predominantly cooperative governance. That contrast makes the Madrid Protocol’s environmental protection regime genuinely unusual in international law. No comparable single instrument governs a similar geographic area under equivalent environmental protection standards.

Port State Control inspection and flag-state authorisation

Port State Control (PSC) inspection for Antarctic-bound vessels operates principally at the gateway ports of Hobart, Christchurch, Punta Arenas, Ushuaia and Cape Town, under the Tokyo MoU (Hobart, Christchurch), the Vina del Mar Agreement (Punta Arenas, Ushuaia) and the Indian Ocean MoU (Cape Town), supplemented by Antarctic-specific verification.

Pre-departure PSC inspection focuses on: Polar Ship Certificate validity and consistency with the planned voyage; PWOM content and currency; ice-class certification under the IACS PC system; bridge-team and crew training credentials including STCW Polar competencies; fuel-system compliance with the MARPOL Annex I Regulation 43 HFO carriage ban; MARPOL Annex IV/V sewage and garbage management equipment; and ballast water management compliance.

For tourist vessels, Argentine and Chilean Coast Guard authorities additionally verify compliance with IAATO operating procedures, including landing-site notifications, passenger-load declarations and biosecurity confirmations. The IAATO Pre-Departure Checklist is widely incorporated into voyage preparation.

Flag-state authorisation adds a parallel layer. The Australian Antarctic Treaty (Environment Protection) Act 1980 (as amended), the British Antarctic Act 1994 and 2013, the United States Antarctic Conservation Act 1978, the New Zealand Antarctica (Environmental Protection) Act 1994 and equivalent statutes in other ATCP states impose authorisation requirements on operators. The combined PSC, IAATO operator-side compliance, and flag-state authorisation regime provides multi-layered enforcement of the Protocol obligations.

Climate change context and the 2048 outlook

The IPCC Sixth Assessment Report (AR6), with the Working Group I physical science basis adopted in 2021 and the Synthesis Report in 2023, strengthened the scientific consensus on Antarctic ice-sheet instability. The West Antarctic Ice Sheet (WAIS) is increasingly vulnerable to marine ice-sheet instability and marine ice-cliff instability, with the Pine Island Glacier and Thwaites Glacier in the Amundsen Sea sector showing accelerating ice loss. The East Antarctic Ice Sheet, long considered stable, shows localised vulnerability in the Wilkes Land and Aurora Basin sectors. The Antarctic Peninsula has warmed faster than the global average, with associated ice-shelf disintegration including the Larsen B collapse in 2002 and the ongoing Larsen C calving sequence from 2017.

The Madrid Protocol regime intersects with the climate-change context primarily through Annex I (EIA processes for new infrastructure must account for shifting ice and weather conditions), Annex V (ASPA boundaries and management plans must adapt to changing ecological distributions), and the broader CCAMLR ecosystem management which is adapting to shifting Southern Ocean productivity and species distributions.

The 2048 Article 25.5 review will occur in a radically different climate, political and technological context than the 1991 negotiation. Renewable energy’s advance, post-fossil-fuel economic structures, climate-driven changes to Antarctic access and ice conditions, and the geopolitical evolution of the Treaty System will all shape the 2048 diplomatic landscape. The procedural and substantive thresholds in Article 25.5 are demanding enough that a significant loosening of the mining ban before mid-century is unlikely, but the review process will be the most consequential Antarctic Treaty event since the original Protocol negotiation.

The completion of Annex VI ratification is the most immediate post-2025 priority. With only approximately 13 of 28 required ATCPs having deposited instruments as of 2025, more than a decade after Australia, the UK and Netherlands ratified in 2014, the remaining hold-outs face continuing diplomatic pressure at successive ATCMs. Activation of the Annex VI liability regime would substantially strengthen the operator-side environmental incentive structure and provide a financial backstop for response to environmental emergencies in one of the world’s most remote and environmentally sensitive regions.

Limitations

The Madrid Protocol regime has structural limits worth noting for maritime practitioners. The Protocol directly binds only vessels of ATCP flag states; non-party flag-state vessels are not subject to Annex IV absent MARPOL or Polar Code coverage. The consensus decision-making requirement at ATCM and CCAMLR creates a structural vulnerability to blocking by individual states on contested measures, as the CCAMLR MPA negotiations illustrate. Annex VI’s liability regime has been non-operative for twenty years since adoption and cannot backstop environmental emergency response until full ratification is achieved.

The geographic scope at 60 degrees south mismatches the CCAMLR Convention area at the Antarctic Convergence (approximately 50 to 60 degrees south), creating a regulatory gap for some marine ecosystems. Enforcement against non-ATCP vessels relies on MARPOL and Polar Code coverage rather than the Protocol itself. And the Annex I EIA process, while thorough, is advisory at the ATCM level: a national programme can proceed with an activity after CEP review regardless of the CEP’s opinion, as long as the party has conducted the prescribed assessment process.

These limits don’t undermine the Protocol’s achievement. The environmental protection designation, the mining prohibition, the five in-force Annexes, the HFO ban, and the Polar Code together constitute the most advanced multilateral environmental regime for any large geographic area on Earth. But practitioners working with Antarctic-bound vessels, national programme logistics, or regulatory compliance should understand that the regime is a layered multi-instrument architecture, not a single comprehensive code.

See also

• Antarctic Special Area and Polar Code
• Polar Code
• MARPOL Convention
• MARPOL Annex V garbage discharge
• MARPOL Annex IV sewage
• MARPOL Annex VI Regulation 13 NOx tier
• MARPOL Annex VI Regulation 14 sulphur cap
• London Convention 1972 / Protocol 1996
• OSPAR Convention 1992
• Helsinki Convention 1992
• Ballast Water Management Convention
• Black carbon Arctic shipping
• Calculator catalogue

References

The primary sources for this article are the Antarctic Treaty Secretariat portal at ats.aq: the Protocol on Environmental Protection to the Antarctic Treaty adopted Madrid 4 October 1991 (Annexes I-V in force 14 January 1998 and 24 May 2002 respectively); Annex VI adopted by Measure 1 (2005) ATCM XXVIII Stockholm, not yet in force; and the Antarctic Treaty 1959 in force 23 June 1961. CCAMLR sources include the CCAMLR Convention 1980 (in force 7 April 1982), Conservation Measure 91-05 (Ross Sea MPA, entry into force 1 December 2017), Conservation Measure 51-07 (krill trigger level) and CCAMLR Fishery Reports for Area 48 krill catch data (2023: 424,203 t; 2024: 498,350 t). IMO sources include the Polar Code (MEPC.264(68) adopted 15 May 2015; MSC.385(94) adopted 21 November 2014; in force 1 January 2017), MARPOL Annex I Regulation 43 (in force 1 August 2011, Antarctic HFO ban), and Resolution MEPC.327(75) (adopted November 2020, Arctic HFO ban from 1 July 2024). IAATO source: ATCM46 IP102 rev.1, IAATO Overview of Antarctic Vessel Tourism 2023-24 Season (122,072 visitors). Full citation links appear in the frontmatter.