Great Barrier Reef

Significance

Off Australia's north-east coast, the Great Barrier Reef contains what UNESCO describes as the world's largest collection of coral reefs, with about 400 types of coral, 1,500 fish species and 4,000 types of mollusc. UNESCO also lists it as a habitat for threatened species such as the dugong and the large green turtle. It was inscribed in 1981 under natural criteria (vii), (viii), (ix) and (x).

Current Status Rationale

Historical damage is documented in the site's record (mass bleaching in 2016, 2017, 2020, 2022 and 2024), but the current classification is based on present conditions and the most recent credible evidence. The present picture is mixed. Against Critical Concern: GBRMPA says the reef retains its outstanding universal value; AIMS's survey published 11 August 2026 shows northern coral cover back to 35.1% (above the program's long-term average of 27.0%) and central cover at 31.6% (above its long-term average of 20.0%), with the southern region at 26.4%, below its long-term average of 29.3%; heat stress in summer 2025-26 was lower than in the previous two summers and surveys found low levels of bleaching, helped by late-summer monsoon cloud and cooler water (although AIMS also notes that a regional bleaching event was declared in the Northern Management Region and that bleaching likely limited coral-cover gains); and the World Heritage Committee in July 2026 noted with appreciation a finalized water quality strategy, welcomed vegetation-clearing reforms and noted with appreciation that the crown-of-thorns control programme has proven to be an effective management action. For High Concern: the 2024 mass bleaching caused the largest annual declines AIMS has recorded in its northern and southern regions (as reported in its 2024/25 report); the Committee in 2026 noted with utmost concern the continuing negative impact of declining hard coral cover and asked for a full assessment of cumulative bleaching impacts; GBRMPA's 2024 Outlook Report describes an outlook of future deterioration due largely to climate change; Cyclone Narelle (Category 5, March 2026) caused further declines on two surveyed reefs with full assessment still to come; and a fifth crown-of-thorns outbreak wave appears to be emerging in the northern region. The AIMS program leader describes the reef as resilient but under pressure with limited capacity to recover. Confidence is Supported rather than Confirmed: the facts about bleaching, coral cover and Committee positions come from primary UNESCO decision pages and Australian Government science agencies, but the State Party's 2026 state of conservation report, the IUCN/World Heritage Centre technical review and the IUCN World Heritage Outlook 2025 assessment itself were not read in this pass, and the whole-property extent of damage is not established by the survey-based figures. Confidence does not alter the status.

Serious, currently active threats are documented, or major historical damage remains substantially unrepaired. Credible sources support this status, with some limits on corroboration.

Threat Categories

Historical Timeline

1. 2020-12-04
   IUCN rates Great Barrier Reef outlook 'critical' for the first time

   Reuters, via Al Jazeera, reported that the IUCN moved the reef's conservation outlook to 'critical' and deteriorating for the first time. IUCN said climate change is the greatest threat and cannot be addressed at site level, while local threats such as fishing and coastal development can be managed; it cited coral bleaching in 2016, 2017 and 2020.

   Sources: Al Jazeera (republishing Reuters)

2. 2023
   World Heritage Committee decision 45 COM 7B.13

   The Committee noted four mass coral bleaching events since 2016 (attributed to climate change), including an unprecedented event in 2022, expressed serious concern at slow progress on water quality, asked Australia to fully implement the recommendations of the 2022 Reactive Monitoring mission and to submit a progress report by 1 February 2024. It stated that the property's urgent conservation needs call for broad mobilisation, including possible inscription on the List of World Heritage in Danger. It did not inscribe the property.

   Sources: UNESCO World Heritage Centre

3. 2024
   Mass coral bleaching event

   AIMS's 2024/25 report describes a 2024 mass bleaching event as the primary source of coral mortality in its surveys, with fast-growing Acropora corals among the hardest hit. The World Heritage Committee refers to the 2023/2024 mass bleaching event in its 2024 and 2025 decisions.

   Sources: UNESCO World Heritage Centre, UNESCO World Heritage Centre, Australian Institute of Marine Science (AIMS), Long-Term Monitoring Program

4. 2024-08
   GBRMPA releases Great Barrier Reef Outlook Report 2024

   The Great Barrier Reef Marine Park Authority published its five-yearly Outlook Report (page updated 23 August 2024). It describes an outlook of future deterioration due largely to climate change, states that outstanding universal value remains intact while integrity is under growing challenge, and does not cover the 2023-24 mass bleaching event. The covering letter describes the overall outlook as very poor.

   Sources: Great Barrier Reef Marine Park Authority, Great Barrier Reef Marine Park Authority

5. 2025
   World Heritage Committee decision 47 COM 7B.2

   The Committee noted with utmost concern the 2024 Outlook Report's conclusions (continued deterioration largely due to climate change; ecosystem outlook 'very poor'), said mass bleaching events including 2023/2024 have negatively affected the property's Outstanding Universal Value, regretted that the 2025 sediment and nitrogen water quality targets were missed, and asked for an updated state of conservation report by 1 February 2026.

   Sources: UNESCO World Heritage Centre

6. 2025-08-06
   AIMS reports large annual declines in coral cover

   AIMS's Annual Summary Report of Coral Reef Condition 2024/2025 reported hard coral cover falling from 39.8% to 30.0% in the northern region (described as the largest annual decline recorded for that region since monitoring began), from 33.2% to 28.6% in the central region and from 38.9% to 26.9% in the southern region (described as the largest region-wide annual decline yet recorded). It primarily attributed the decline to coral mortality from the 2024 mass bleaching event.

   Sources: Australian Institute of Marine Science (AIMS), Long-Term Monitoring Program

7. 2025-10
   IUCN World Heritage Outlook 4 reportedly again rates the reef 'critical'

   The Australian Marine Conservation Society (an advocacy NGO) and a regional news site reported that IUCN's World Heritage Outlook, released at the IUCN World Conservation Congress in Abu Dhabi in October 2025, again rated the reef's outlook 'critical' and that it was the only site relisted as 'critical' that has not been added to the Danger List. IUCN's own publication page confirms the 2025 report exists (assessing 271 natural and mixed sites) but the report itself was not read, so this rating is single-chain reporting and was not used to determine status.

   Sources: Australian Marine Conservation Society (AMCS), Newsport (archive), IUCN

8. 2026-03
   Cyclone Narelle crosses northern Great Barrier Reef

   AIMS reports that Cyclone Narelle (Category 5) crossed the northern region in March 2026 and caused reef-wide coral declines of up to 5% on two offshore reefs near Lizard Island; a full assessment is to follow surveys in 2027. Earlier, Cyclone Koji (Category 1, central region, January 2026) caused minor coral losses on several reefs.

   Sources: Australian Institute of Marine Science (AIMS), Long-Term Monitoring Program, Australian Institute of Marine Science (AIMS)

9. 2026-07
   World Heritage Committee decision 48 COM 7B.69; property not placed on Danger List

   The Committee noted with utmost concern the continuing negative impact on Outstanding Universal Value, mainly from declining hard coral cover after the 2024/2025 mass bleaching events, asked for a full assessment of the latest bleaching event once available, noted with appreciation the finalized Reef 2050 Catchment Water Quality Strategy, welcomed vegetation-clearing reforms, noted with appreciation the crown-of-thorns control programme, and requested a progress report by 1 December 2028 and an updated state of conservation report by 1 December 2029. The decision text reviewed contains no Danger List statement. AFP reported on 4 July 2026 that UNESCO's draft decision would avoid an 'in danger' listing and that the Australian government welcomed it; the exact adoption date of the final decision was not confirmed here, so the month is shown.

   Sources: UNESCO World Heritage Centre, UNESCO World Heritage Centre, The Korea Times (republishing AFP)

10. 2026-08-11
    AIMS reports partial coral cover recovery

    AIMS's Annual Summary Report of Coral Reef Condition 2025/26 reported hard coral cover of 35.1% in the northern region (up from 30.0%), 31.6% in the central region (up from 28.6%, within margin of error) and 26.4% in the southern region (down from 26.9%, within margin of error). Of 121 reefs surveyed, 28% increased, 56% showed no net change and 16% declined. AIMS's program leader said the reef is showing resilience but its capacity to recover is limited.

    Sources: Australian Institute of Marine Science (AIMS), Long-Term Monitoring Program, Australian Institute of Marine Science (AIMS)

Digital Preservation Index

Overall coverage: Moderate — Documented in several categories, with some notable gaps.

Three of five categories have publicly viewable evidence found in this pass (photographic, virtual tour, academic/scholarly), which meets the moderate tier by the rubric (2-3 categories). Coverage is thin for a property of this size. The photographic evidence is UNESCO's gallery (12 thumbnails shown on the page, 3 pages, with the 'See All' link requesting 28 items, which suggests about 28 in total; credits are to two photographers). The virtual tour found is a single Google Arts & Culture panorama at Saunders Reef, not a tour of the whole property. The academic/scholarly category rests on AIMS's public annual monitoring reports and the Allen Coral Atlas's satellite-based benthic, geomorphic and bathymetric maps of the central Great Barrier Reef (about 10% of the reef, per its 2019 post). Archival records are not counted: the GBRMPA Outlook Report 2024 website (a statutory management assessment) and UNESCO's state of conservation reports and decisions are management or governance assessments, not archives of documentation of the property. No publicly viewable 3D model was confirmed: an AIMS news item of 10 June 2024 reports a photo-realistic 3D digital twin of a section of the reef produced with La Trobe University, but no public viewer or location was found, so 3D documentation is not counted. The record is primarily scientific (monitoring and mapping) rather than heritage documentation, and the Allen Coral Atlas is satellite-based habitat mapping rather than site documentation in the heritage sense, so even the moderate tier rests partly on borderline evidence.

• Photographic

  UNESCO World Heritage Centre hosts a public photo gallery for the property (12 images visible on the page opened, credited to Evergreen and Silvan Rehfeld; pagination suggests about 28 in total).

  View source
• Virtual Tour

  Google Arts & Culture's ocean story offers an interactive 'Take a virtual tour of the Great Barrier Reef' panorama at Saunders Reef (tap and drag to look around). It is a single scene, not a tour of the whole property.

  View source
• Academic Scholarly

  AIMS's Long-Term Monitoring Program publishes annual public summary reports of coral reef condition from manta-tow surveys of over 120 reefs.

  View source
• Academic Scholarly

  The Allen Coral Atlas provides openly viewable online benthic, geomorphic and bathymetric maps; its May 2019 post reports 237 central Great Barrier Reef reefs (about 3,000 sq km, roughly 10% of the Great Barrier Reef) viewable online, mapped with the University of Queensland's Remote Sensing Research Centre and Arizona State University.

  View source

Law and commitments

• Treaty record for Australia