February 2026: As a result of focussed discussions with members of the IUCN Species Survival Commission Penguin Specialist Group, we have agreed to post a revised version of this topic. The initial version is available here.
Emperor Penguin (Aptenodytes forsteri)
Given the population devlopment over recent years and the projected further decrease in sea ice coverage I fully support the new classification as vulnerable.
I have reviewed the evidence and fully support the suggested change from Near Threatened to Endangered for the Emperor Penguin given the rapid rate of sea ice loss and its effects on breeding success for this species.
I fully support the new classification as Endangered for the emperor penguin, give the loss of sea ice and impact on breeding outcomes for this species.
On behalf of IUCN co-authors David Ainley, Christophe Barbraud and Michelle LaRue:
We find issues with the information presented in this forum and have sent our concerns by email to the Red List team. Herein are our concerns with respect to Annex 1.
The estimates provided in the BirdLife International version of 450,000 to 520,000 mature individuals is incorrect. The population size (from 50 colonies), as based on estimates derived from high-resolution is 228,000 adult birds in attendance at colonies in the springtime as of 2018 (LaRue et al. 2024). Whether springtime estimates are an index of breeding pairs is unknown, though evidence suggests springtime estimates are a proxy for fledging abundance (Sen et al. 2025).
The text “…equivalent to a median three-generation reduction of 58%, (95% CI = -3.3% to +1.0%),” is inappropriate. It is inaccurate to assume that any identified trajectory will continue unabated and as-is into the future.
The text, “While there are large uncertainties, particularly noting the limited scope of the data, if this rate applies across the population it implies the decline is already rapid over the current and future three-generation period.” should say, “While much remains to be learned, given the relatively limited scope of the data, and given the rapid decline observed, it is now important to determine whether this rate applies to the global population, including within the current estimated three-generation period.” The meaning of these two sentences is quite different, and expert review (the latter sentence) acknowledges further study is required to determine if the rate of decline applies to the three-generation period, as this is unknown. A rate of observed decline over a subsection of colonies for 15 years cannot be: 1. applied to other colonies, nor 2. can that rate be assumed to at all continue for three generations (67 years), within the subsection of colonies, or elsewhere.
The text, “If the population were stable prior to 2009 but subsequently declined by 9.6% to 2018 (as estimated by LaRue et al. [2024]) the overall reduction for the past three generations is around 11%. As declines likely commenced sooner, the past reduction is inferred to fall between 11 and 29%.” is speculation, based on assumptions of trend lines extending backwards and forwards to match the rates calculated over ten years. This is inappropriate.
Regarding, “continuing decline in mature individuals” being “yes” and “estimated” here differs from expert review. The qualifier experts used was “Projected”, not “Estimated”.
Regarding “Number of subpopulations: 1″… To the question, “All individuals in one subpopulation”, within the IUCN expert review, the response was “No”. There are three genetic studies suggesting emperor penguins are either panmictic (Cristofari et al. 2015), comprised of two populations (Younger, Clucas et al. 2015) or comprised of at least four metapopulations (Younger, Clucas et al. 2017).
The sentence, “These changes in the sea ice environment put pressure on emperor penguins as the extent of their breeding habitat decreases, and the sea ice season shortens, potentially decreasing breeding success, whilst moult habitat is reduced which affects adult survival (Trathan et al. 2024).” is inaccurate. The sentence should say, “These changes in the sea ice environment put pressure on emperor penguins as the extent of their habitat decreases, and the sea ice season shortens, potentially diminishing breeding, foraging and moult habitat, the last of which likely affects adult survival”. The forum version added, “breeding” before the word habitat, and changed to “decreasing breeding success”, removed other habitat types, and changed the emphasis on moulting habitat. This sentence should be about habitat and this forumversion revised to include breeding success inappropriately.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments until 2 February 2026. We will now analyse and interpret the information, and we will post a preliminary decision on this species’ Red List category on this page on 2 February 2026, when discussions will re-open.
As a result of focussed discussions with members of the IUCN Species Survival Commission Penguin Specialist Group, we have agreed to post a revised version of this topic (posted above). The initial version is available here.
Many thanks for the comments received on this proposal. Please review the revised topic and respond if your view has changed.
The major change relates to the confidence the initial proposal stated that the population was already undergoing rapid declines. The expert review was clear that the data were not appropriate to extrapolate a rate of reduction to the global population. The published data on which this was based are an index from satellite imagery and can only be used to state the probability that the number of adult birds in spring was lower in 2018 than 2009 (La Rue et al. 2024). The second published paper, using similar methods (Fretwell et al. 2025), covered only around a third of the global population.
The following key points have changed:
1: the past rate of population reduction is now considered ‘Unknown’, rather than being inferred to fall between 11-29 %.
2: the past and future rate of reduction is also now considered ‘Unknown’, rather than suspected to align with the future rate of population reduction.
3: The qualifier for the continuing decline in mature individuals is change to ‘Projected’ to reflect that it is based on the projected declines from the ensemble population modelling, rather than an index of change in the number of mature individuals.
4: A change to the population size has also been made to 228,000 mature individuals with a range based on 95% credible intervals of 190,000-280,000 (LaRue et al. 2024), noting that this is based on a population index from satellite images rather than direct counts.
Generally greater detail has been included to fully document the reasons for change in status at this time.
Preliminary proposal
Based on these revisions, our preliminary proposal for the 2026 Red List would be to list Emperor Penguin as Endangered under Criterion A3bc.
There is now a period for further comments until the final deadline on 8 February 2026, after which the recommended categorisations will be put forward to IUCN.
The final 2026 Red List categories will be published on the BirdLife and IUCN websites later this year, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested in commenting. The window for consultation is now closed and we are unable to accept any more comments. We will analyse and interpret the information, and a final decision on this species’ Red List category will be posted on this page on 16 February 2026.
Recommended categorisation to be put forward to IUCN
The final categorisation for this species has not changed. Emperor Penguin is recommended to be listed as Endangered under Criterion A3bc.
Many thanks to everyone who contributed to the 2026.1 GTB Forum process. The final Red List categories will be published on the BirdLife and IUCN websites later this year, following further checking of information relevant to the assessments by both BirdLife and IUCN.