The products were Beyer, CHELSA-TraCE21k, EcoClimate, PALEO-PGEM-Series and WorldClim. Their spatial resolutions ranged from 0.008° for CHELSA-TraCE21k to 1° for PALEO-PGEM-Series, while their temporal coverage, underlying climate models and downscaling approaches also differed. The analysis did not determine whether the observed discrepancies originated in the climate simulations, downscaling procedures, proxy records or a combination of these factors.

To assess modelled cooling, the researchers extracted temperature-change estimates at 174 locations represented by two proxy compilations by Farrera et al. (1999) and Bartlein et al. (2011). The records consisted of fossil pollen and plant macrofossil data from radiocarbon-dated sediment records. Fifty-nine locations were inside mountain ranges delineated by the Global Mountain Biodiversity Assessment inventory, and 115 were outside them.

At each location, the authors compared the difference between present and LGM temperatures in each dataset with the corresponding proxy-derived difference. The five products generally estimated warmer LGM conditions than the proxies, indicating less cooling. Outside mountain ranges, median deviations from the proxy estimates for WorldClim, Beyer and EcoClimate were −0.08 °C, 0.28 °C and 0.14 °C, respectively. CHELSA-TraCE21k, PALEO-PGEM and the global grid cooling comparison had larger deviations of 1.11 °C, 1.35 °C and 1.33 °C.

Within mountain ranges, all five datasets had warmer median LGM temperatures than the proxy records. Median deviations were 2.1 °C for CHELSA-TraCE21k, 0.8 °C for WorldClim, 1.27 °C for Beyer, 0.9 °C for EcoClimate and 1.38 °C for PALEO-PGEM. The global grid cooling method, which subtracted a uniform 4.673 °C cooling estimate from the present-day CHELSA-TraCE21k raster, had the smallest median deviation in mountains at 0.33 °C. Its difference from the proxy estimates was significantly smaller within mountains than outside them at p < 0.01; the corresponding in-mountain versus out-of-mountain effect was not significant for the other methods.

A hierarchical generalised additive model using restricted maximum likelihood examined how dataset–proxy differences varied with latitude. The geographic pattern was not uniform. The datasets generally underestimated LGM cooling in the tropical mountains of Central and South America, including the northern and central Andes, and in South Africa. In parts of western and northwestern North America, continental Asia, Southeast Asia and Oceania, they instead overestimated cooling relative to the proxies. Differences were relatively stable across the Southern Hemisphere but more variable in the Northern Hemisphere. Some large negative differences occurred mainly at northern high-latitude locations, where proxy-derived LGM temperatures were 8 °C and 13 °C higher than corresponding dataset estimates.

To demonstrate the consequences of the temperature differences, the researchers reconstructed temperature-delimited treelines. For eligible mountain ranges, they extracted the temperature associated with the present-day treeline location from CHELSA v2.1, then located the LGM elevation at which each paleoclimate dataset and the global grid cooling method reached that temperature, allowing a margin of ±0.25 °C for resolution constraints. Elevation data were resampled to the spatial resolution of each climate product, and minimum, maximum, mean and standard deviation treeline elevations were calculated for each range.

Reconstructed treeline elevations differed by thousands of metres among datasets in some ranges, including the Tian Shan, Hindu Kush and central Andes, while other ranges showed closer agreement. Maximum differences exceeding 3,000 m occurred especially in the Americas, including the Rocky Mountains, Pacific Coast Ranges, Cordillera de la Costa and southern Andes. The global grid cooling method yielded a treeline estimate for 70 of 75 mountain ranges, compared with 67 for CHELSA-TraCE21k. Coarse-resolution products did not consistently capture smaller ranges and islands.

Spatial resolution also affected how products represented temperature gradients with elevation. In the Central European Highlands, Beyer, EcoClimate and PALEO-PGEM assigned single temperature values across broad elevation ranges, whereas CHELSA-TraCE21k and WorldClim showed a clearer decline in temperature with increasing elevation. The study was a global comparison and sensitivity analysis rather than an evaluation of a single reconstruction method. Its limitations included uneven proxy coverage, sparse records in many mountain ranges and uncertainties in proxy estimates. The results show that mountain and biome reconstructions based on paleoclimate products can depend materially on dataset resolution, regional bias and the method used to estimate LGM temperature change.

Subject of Research: Comparative assessment of Last Glacial Maximum temperature datasets and their effects on mountain treeline reconstructions

Article Title: Global variability in LGM cooling amongst paleoclimate datasets affects biome reconstructions in mountains

Article References: Rentier, E. S., Mottl, O., Pacheco-Riaño, L. C., Schultz, L., Seguinot, J., Wiersma, A. T., Grytnes, J.-A., & Flantua, S. G. A. (2025). Global variability in LGM cooling amongst paleoclimate datasets affects biome reconstructions in mountains. Frontiers of Biogeography, 18, Article e135871. https://doi.org/10.21425/fob.18.135871

Image Credits: AI Generated

DOI: 10.21425/fob.18.135871

Keywords: Last Glacial Maximum, paleoclimate modelling, treeline reconstruction, mountain biomes, mean annual temperature, proxy records, spatial resolution, biogeography, climate cooling, comparative analysis, Global, variability

The research, led by Laura Boyall of Royal Holloway University of London and Bangor University, together with Alice Milner, Klaus Dodds, and Celia Martin-Puertas, took an unusually direct approach: they interviewed the people on both sides of the divide. Six policy advisors from UK Civil Service departments — including the Department for Energy Security and Net Zero, Defra, the Foreign, Commonwealth and Development Office, and the Environment Agency — and five senior palaeoclimate scientists from UK universities were questioned in semi-structured interviews about how they perceive, produce, and use evidence about past climates. The transcripts were then analysed using reflexive thematic analysis, with codes developed inductively from the data and grouped into three overarching themes: evidence, context for climate change, and temporal resolution.

The most striking finding concerns where decision makers actually get their climate information. The interviews revealed what the authors describe as an evidence hierarchy, and at its very top sit the assessment reports of the Intergovernmental Panel on Climate Change. Every single decision maker interviewed named the IPCC as their preferred first source, citing its role as a single, trusted synthesis of thousands of peer-reviewed studies, its rigorous review process, and — for those working on international policy — its global acceptance. Below the IPCC came boundary organisations and knowledge brokers such as the Met Office, the World Meteorological Organisation, World Weather Attribution, and the Climate Change Committee, followed by commissioned research, government websites, and only then peer-reviewed journal articles. Expert advice and seminars sat at the very bottom of the hierarchy, used rarely despite being valued when they occur.

That lowly position for journal articles is significant, because it is precisely where most palaeoclimate evidence lives. The study explains that academic papers are written by scientists for scientists, dense with methodological detail, specialist terminology, and field-specific background that makes them slow to digest for officials working under tight deadlines. Single studies also need to be interpreted alongside a wider body of literature to be meaningful, making them less directly useful than syntheses. And there is a more mundane obstacle: many relevant papers sit behind paywalls that policy departments cannot afford to breach, pushing officials toward freely accessible alternatives. In other words, the default dissemination format of palaeoclimate research is almost perfectly misaligned with how its potential users actually consume evidence.

On the substance, there was genuine agreement between the two groups. Both scientists and decision makers agreed that palaeoclimate has a real role to play, above all in contextualising current and future warming. Records of past climates show how the climate system behaves over centuries and millennia, revealing the full range of natural variability and the frequency of rare but high-impact events that the short instrumental record simply cannot capture. Without that longer baseline, the study notes, policymakers risk systematically under- or over-estimating the likelihood of extremes, misidentifying the drivers of climate variability, and failing to anticipate thresholds or abrupt transitions. Palaeoclimate scientists interviewed for the study described contributing summaries of ecosystem tipping points and reconstructions of past water availability directly to the Foreign Office, and one remarked that everything we know about the climate system is ultimately based on understanding the past.

Yet the interviews also exposed a stubborn practical problem: time. Policy operates on electoral cycles and planning horizons of a few years to a few decades, while many palaeoclimate reconstructions resolve change only on centennial to millennial scales. One decision maker described hitting a wall of insufficient granularity, unable to extract from a coarse reconstruction any information useful for, say, mapping flood risk from a rapid-onset rainfall event. Another noted bluntly that if a graph of past climate looks like a straight line at 100-year resolution, a policymaker has little they can act on. Interestingly, the study suggests the problem is partly one of perception rather than fact: not all decision makers were aware that palaeoclimate reconstructions can achieve decadal or even annual resolution. The mismatch, the authors argue, reflects a failure to communicate why longer timescales matter, not an inherent irrelevance of the data.

Communication emerged as the principal barrier across all three themes — both the format in which palaeoclimate is disseminated and the messaging about its relevance. The study situates this within a well-documented critique of the so-called deficit model, the assumption among many scientists that publishing a paper initiates a linear flow of knowledge into policy. In reality, evidence use is indirect and shaped by institutional cultures, trust, timing, and political priorities. One decision maker even noted a preference for publicly funded research, treating public funding as a safeguard against perceived bias. The academic reward structure compounds the problem: under the UK’s Research Excellence Framework, traditional publications carry a 60 percent weighting in institutional assessments while impact beyond academia counts for just 25 percent, giving researchers little institutional incentive to engage with policy at all.

The authors do not leave the problem hanging. They distil a set of actionable recommendations aimed squarely at palaeoclimate scientists. First, write policy briefs: short, jargon-free summaries of the policy-relevant parts of a study, which surveys in other disciplines have found to be among the most effective tools for crossing the science-policy interface. Second, pursue transdisciplinary collaboration, embedding palaeoclimate evidence within research that already incorporates the socioeconomic and political dimensions that shape real decisions. Third, seek science-policy training, ideally through secondments and placement schemes such as those listed by the UK Government Office for Science, which build networks and first-hand understanding of how evidence is actually used. Fourth, and most importantly, embrace co-production — working with decision makers and boundary organisations such as the Met Office from the very start of a research project, so that the questions asked, the resolutions targeted, and the outputs produced are aligned with genuine policy needs from day one.

There are encouraging signs that the tide may be turning. Within the IPCC’s most recent assessment report, palaeoclimate content was deliberately distributed throughout the document rather than confined to standalone chapters, meaning that officials absorbing the report encounter long-term climate context naturally, without needing to seek it out. The study also points to the influence of individuals: decision makers with a palaeoclimate background could far more readily identify where such evidence would be useful, and past Chief Scientific Advisers — including Defra’s former CSA Gideon Henderson, an Earth-system scientist — have brought exactly that training into government. The authors acknowledge their study’s limitations, including a small sample of eleven interviews and a UK-specific focus, and they call for similar work across other national and supranational policy environments and a broader range of stakeholder groups. But the core message is clear and urgent: the past holds evidence the future desperately needs, and the barrier is not the science — it is the conversation around it. Fix that, the researchers argue, and palaeoclimate could finally take its place alongside instruments and models in the evidence base on which climate policy is built.

Subject of Research: Barriers and facilitators to integrating palaeoclimate evidence into UK climate policy decision making

Article Title: Barriers and facilitators for using palaeoclimate evidence in UK climate decision making

Article References: Boyall, L., Milner, A. M., Dodds, K., & Martin-Puertas, C. (2026). Barriers and facilitators for using palaeoclimate evidence in UK climate decision making. Geoscience Communication, 9(2), 275-289. https://doi.org/10.5194/gc-9-275-2026

Image Credits: AI Generated

DOI: 10.5194/gc-9-275-2026

Keywords: palaeoclimate, climate policy, science-policy interface, UK Civil Service, IPCC, evidence hierarchy, knowledge exchange, co-production, policy briefs, climate decision making, proxy records, Geoscience Communication

The methodology behind the study is straightforward but rigorous. The authors searched Scopus, the multidisciplinary citation database launched by Elsevier in 2004, using keywords such as climate change, paleoclimate, Holocene, climate variability and Quaternary, combined with Boolean operators and explicit inclusion and exclusion criteria. After removing duplicates and screening titles and abstracts for relevance, they retained 1,141 articles published across the 22-year window. The dataset was then analyzed and visualized with VOSviewer, the bibliometric mapping software developed at Leiden University’s Centre for Science and Technology Studies, alongside Microsoft Excel. This allowed the team to track annual publication trends, identify the most productive countries, institutions and authors, map keyword co-occurrences, and construct citation networks linking the field’s core journals. The authors are careful to note that their findings depend entirely on the coverage, accuracy and classification practices of Scopus itself, a caveat that shapes how the results should be read.

The temporal trends reveal a field in sustained expansion, though not without turbulence. In 2002, the earliest year of the analysis, only 26 documents appeared in the search results. Output climbed irregularly thereafter, with a sharp jump between 2012 and 2013, when the count leapt from 42 to 73 papers, and another surge between 2016 and 2018, culminating in a peak of 84 publications in 2018. The trajectory was not monotonic: 2014 saw a steep fall back to 42 documents, and 2022 dropped to 58 after hovering between 65 and 73 in the preceding years, before recovering slightly to 68 in 2023. These oscillations, the authors suggest, may reflect irregularities in publication patterns or in how the database collects and indexes records. The overall message, however, is unambiguous: scientific interest in Holocene climate variability has grown substantially over the long term, mirroring broader concern about understanding natural climate baseline conditions against which modern anthropogenic warming can be compared.

The geography of the field is strikingly lopsided. The United States leads with more than 300 publications, followed by Germany with roughly 250 and the United Kingdom with around 225. China ranks fourth with approximately 175 papers, and France contributes about 150. Canada, Australia, Spain, Switzerland and Sweden round out the top ten, each producing between 75 and 125 documents. At the institutional level, the Chinese Academy of Sciences stands out as the single most prolific affiliation, exceeding 100 papers, with France’s CNRS close behind. The University of Bern in Switzerland, Spain’s Consejo Superior de Investigaciones Científicas and Germany’s Alfred-Wegener-Institut Helmholtz-Zentrum occupy an intermediate tier, while Lanzhou University, the Deutsches GeoForschungsZentrum GFZ, China’s Ministry of Education and the University of Minnesota Twin Cities contribute more modest volumes. The map that emerges is one of dense research capability in North America, Western Europe and China, and comparatively thin coverage elsewhere.

Individual researchers show similarly uneven productivity. Melanie J. Leng tops the author ranking with around 18 papers in the dataset, well ahead of R. Lawrence Edwards at roughly 10. Achim Brauer, Hai Cheng and Feng Sheng Hu each published between six and eight papers, while most other highly ranked authors produced fewer than five. In the journal landscape, Quaternary Science Reviews dominates both in output and influence, typically publishing between 5 and 15 relevant papers per year and reaching approximately 15 in 2023. The Holocene follows a fluctuating path of 3 to 10 papers annually, Quaternary International varies between 2 and 8 with growth after 2010, and Palaeogeography, Palaeoclimatology, Palaeoecology records 2 to 7 per year. The Journal of Quaternary Science trails with 1 to 3. Citation network analysis confirms Quaternary Science Reviews as the most influential source, followed by Quaternary International, with related outlets such as Climate of the Past, the Journal of Paleolimnology and Marine Geology anchoring the multidisciplinary edges of the network.

Perhaps the most revealing finding concerns disciplinary breadth. Earth and Planetary Sciences accounted for about 37.7 percent of the publications, the largest single share, but the remainder is scattered across a remarkable range of fields: Environmental Sciences at 18.4 percent, Agricultural and Biological Sciences at 15.9 percent, and Arts and Humanities at nearly the same 15.8 percent, with Social Sciences contributing 8.1 percent. Medicine, chemistry and energy each registered only fractions of a percent. Keyword density mapping reinforces this picture of interdisciplinarity. The word Holocene dominates the center of the co-occurrence network, surrounded by clusters referencing paleoenvironment, precipitation, monsoon and glaciology, alongside oceanographic and isotopic terms such as Atlantic Ocean, oxygen isotope and sea surface temperature. Palynological and sedimentary vocabulary, including lacustrine deposit, pollen and fire history, appears prominently, and terms like genetics, mitochondrial DNA and genetic variability hint at links to biological evolution and species adaptation. Holocene climate research, in other words, is not the province of climatologists alone but a genuinely hybrid enterprise spanning geology, ecology, archaeology and even the humanities.

The study contextualizes this bibliometric portrait within the scientific substance of the field. Holocene climate variability has been reconstructed from a diverse suite of paleoclimate archives, each with distinct strengths. Ice cores from polar regions deliver annual-resolution records of oxygen isotopes with precise dating; speleothems from caves capture seasonal-scale signals in isotope ratios and trace elements; marine sediment cores, rich in foraminiferal assemblages and magnesium-to-calcium ratios, offer centennial-scale resolution with moderate dating accuracy. Pollen assemblages document past vegetation and hydroclimate, charcoal reflects fire activity, and stable isotopes such as δ18O and δ13C are widely used to infer temperature, precipitation sources and moisture balance. The driving mechanisms span multiple timescales: slow orbital forcing from Milankovitch cycles shaped the early to mid-Holocene climatic optimum, while solar variability, volcanic eruptions and internal ocean-atmosphere dynamics, including the Atlantic Meridional Overturning Circulation, the North Atlantic Oscillation and the El Niño-Southern Oscillation, generated abrupt and regionally heterogeneous responses such as the 8.2 ka cooling event. Transient model simulations from the Paleoclimate Modelling Intercomparison Project broadly reproduce orbitally driven trends, though discrepancies persist in the magnitude and timing of regional hydroclimatic shifts, particularly in the tropics and Southern Hemisphere.

The bibliometric data also expose structural weaknesses that the authors argue the field must confront. Regional disparities are pronounced: Europe, North America and China dominate the literature, while Africa and South America remain markedly underrepresented, a gap that echoes the spatial bias already known in proxy data coverage itself. Temporal resolution varies enormously across archives, from annually layered tree rings and ice cores to coarser marine sediments, complicating direct comparison of short-lived climatic events. Chronological uncertainties arising from radiocarbon calibration and reservoir effects further limit the precision of regional syntheses, and proxy sensitivity can differ depending on local environmental conditions. The authors also flag the limitations of their own approach, noting that English-language dominance in the indexed literature, keyword selection and Scopus’s disciplinary classifications all introduce potential biases into the analysis. They call for stronger integration of climate models with high-resolution proxy data, improved dating techniques, and expanded interdisciplinary and global collaboration to fill the geographic and methodological gaps.

Why does this matter beyond the census-taking? Because the Holocene is the stage on which human civilization developed, and its climate history provides the natural baseline against which modern, human-driven warming must be judged. Since the Industrial Revolution, emissions of carbon dioxide and methane have intensified the greenhouse effect to a degree that now overwhelms the natural forcings, orbital, solar and volcanic, that governed Holocene variability for millennia. Understanding how climate behaved under purely natural conditions, and how societies responded to events like the African Humid Period’s abrupt termination or the sapropel S1 interval in the eastern Mediterranean, informs climate resilience strategies, resource management and policy development. The authors expect research on the topic to keep growing in the coming years, and their analysis suggests where that growth is most needed: in the under-sampled regions of the global South, in the integration of models with proxy records, and in the high-resolution chronologies that would let paleoclimatologists pin down exactly when and how fast past climates changed. A field that can map its own blind spots, this study shows, is far better equipped to close them.

Subject of Research: Bibliometric analysis of Holocene climate variability research publications from 2002 to 2023

Article Title: Bibliometric analysis of Holocene climate variability research papers from 2002 to 2023 identifying trends leading contributors and thematic developments

Article References: Bouabid, N., Mnasri, H., Srarfi, F., & Tagorti, M. A. (2026). Bibliometric analysis of Holocene climate variability research papers from 2002 to 2023 identifying trends leading contributors and thematic developments. Discover Geoscience, 4(1), Article 325. https://doi.org/10.1007/s44288-026-00682-4

Image Credits: AI Generated

DOI: 10.1007/s44288-026-00682-4

Keywords: Holocene, climate variability, bibliometrics, Scopus, paleoclimate, VOSviewer, proxy records, Quaternary Science Reviews, research trends, climate forcing, interdisciplinarity, research gaps