Two years after the Anthropocene proposal was rejected, scholars allege the vote was not transparent and call for the documents to be released, while a review of 12 global stratigraphic records reaffirms 1952 plutonium as a viable boundary marker

Renn and co-authors argue in an Earth's Future paper that unpublished documents show the 2024 rejection of the Anthropocene proposal was illegitimate and that the rationale for the decision was never adequately explained; they call on the IUGS to publicly release key documents related to the vote and to submit the process to independent review, to maintain 'public trust in our capacity to understand and respond to planetary transformation'. Earlier debate centered on whether the stratigraphic evidence was sufficient; this paper shifts attention to the transparency and legitimacy of the decision process and is the first to publicly raise a procedural challenge grounded in what the authors describe as unpublished documents. The basis is the unpublished documents the authors cite and their reading of the voting process; the report also gives the opposing position—Adele Bertini, who co-chaired the voting subcommittee, says the process was fair and points to a comment she co-authored last month in Nature Reviews Earth & Environment giving a technical explanation for the rejection.

In a Nature Reviews Earth & Environment review, Waters, Zalasiewicz and colleagues compile multi-proxy evidence from 12 globally distributed stratigraphic records and conclude that mid-twentieth-century Earth system changes are abrupt, globally synchronous and stratigraphically distinct, providing a basis for precisely defining the Anthropocene as a series and epoch. The review consolidates evidence scattered across multiple candidate sections—lakes, corals, ice cores, peatlands, marine basins—into a single argument spanning both hemispheres and climate belts from tropical to Antarctic, and explicitly argues that the 1952 plutonium increase is the most suitable primary marker for the base. Evidence comes from multi-proxy synthesis across 12 stratigraphic records, including plutonium isotopes, stable carbon and nitrogen isotopes, and fly-ash particles; the text reports specific figures such as atmospheric carbon dioxide and methane at 51% and 157% above Holocene levels and global temperatures 1.5 °C above pre-industrial levels.

The review emphasizes that a sharp global plutonium increase in 1952, related to above-ground thermonuclear detonations, provides the most suitable primary marker for the Anthropocene's base, supported by an array of proxies, many unique to the Anthropocene. It narrows the boundary candidate from a broader 'mid-twentieth century' to the specific year 1952 and argues that this marker can be recognized globally and synchronously and correlated precisely on a global scale. The basis is the synchronous appearance of plutonium isotopes and other fallout products across the 12 records, together with supporting proxies such as stable carbon and nitrogen isotopes and fly-ash particles.

Opponents argue the Anthropocene is better treated as a geological 'event' rather than a formal epoch, on the grounds that human impacts before and after 1952 did not overwhelm the Earth system, and that the Holocene—beginning about 11,700 years ago—should remain a time interval of relative stability. This position moves the dispute from whether the evidence is sufficient to which hierarchical category the Geological Time Scale should use, and it now stands alongside the supporters' case in peer-reviewed literature. The report quotes Phil Gibbard, a geologist at the University of Cambridge who voted to reject the proposal, and notes that he and others have argued for treating the Anthropocene as an event; Bertini and colleagues also published a comment last month giving a technical explanation for the rejection.

This work speaks to stratigraphers, managers of the Geological Time Scale, and interdisciplinary researchers who use the term 'Anthropocene'. The 1952 boundary argued in the review applies to stratigraphic archives capable of preserving plutonium fallout and other mid-twentieth-century markers, such as lake varves, corals, ice cores, peatlands and marine basin sediments; the transparency demand applies to the decision process of the International Union of Geological Sciences and its stratigraphic bodies. For readers trying to understand the current state of the Anthropocene debate, these two threads together define the scope of discussion: one about evidence and boundary definition, one about decision procedure and openness.

The report mentions unpublished documents, but their contents are not laid out in the text, so the specific basis of the procedural-legitimacy allegation remains to be verified once released. The review is subscription content, with the full text and figures not completely available, so details beyond the abstract and key points cannot be assessed here. In addition, the classification dispute over whether the Anthropocene should be an epoch or an event continues in parallel in the peer-reviewed literature, and whether an independent review is launched or the IUGS releases documents remains an open question.