Raphaël Hébert
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View article: The colors of proxy noise
The colors of proxy noise Open
The complex biological and physical processes that preserve paleoclimate information over centuries or longer introduce variations in proxy time series that are unrelated to the true climate. These non-climatic variations act on different …
View article: From eons to epochs: multifractal geological time and the compound multifractal - Poisson process
From eons to epochs: multifractal geological time and the compound multifractal - Poisson process Open
Geological time is punctuated by events that define biostrata and the Geological Time Scale’s (GTS) hierarchy of eons, eras, periods, epochs, ages. Paleotemperatures and macroevolution rates, have already indicated that the range ≈ 1 Myr t…
View article: LegacyVegetation: Northern Hemisphere reconstruction of past plant cover and total tree cover from pollen archives of the last 14 kyr
LegacyVegetation: Northern Hemisphere reconstruction of past plant cover and total tree cover from pollen archives of the last 14 kyr Open
With rapid anthropogenic climate change, future vegetation trajectories are uncertain. Climate–vegetation models can be useful for predictions, but they require extensive data on past vegetation for validation and improving systemic unders…
View article: Lacking oceanic-driven internal multidecadal climate variability is compensated by forced variability in model simulations
Lacking oceanic-driven internal multidecadal climate variability is compensated by forced variability in model simulations Open
Regional climate change in the $21^{st}$ century will result from the interplay between human-induced changes and internal climate variability. Competing effects from greenhouse gas warming and aerosol cooling have historically caused mult…
View article: On the suitability of data assimilation products to quantifying variability and teleconnections across scales
On the suitability of data assimilation products to quantifying variability and teleconnections across scales Open
Data assimilation techniques, such as the Kalman Filter, have enabled the development of complete climate field reconstructions over the last millennium, commonly referred to as paleoclimate reanalysis. These techniques effectively integra…
View article: Spectral divergence in hydroclimate and temperature between models and reconstructions 
Spectral divergence in hydroclimate and temperature between models and reconstructions  Open
The relatively short observational record limits our ability to understand the long-term variability of key climate factors like temperature and hydroclimate. Climate models and paleoclimate proxies appear to have long-term temperature var…
View article: Scaling Geochronologies
Scaling Geochronologies Open
Much of our knowledge of the Earth’s past is gleaned by interpreting varying layers in outcrops, cores drilled through lake and ocean sediments, and sheets of rock and ice. These were laid down under highly variable conditions and their st…
View article: The Colors of Proxy Noise
The Colors of Proxy Noise Open
Uncertainty in paleoclimate time series is inherent to the complex biological and physical processes involved in forming and archiving them in the environment for centuries or longer. The timescale-dependency of this uncertainty is often r…
View article: Lack of evidence for alternative stable states in Northern Hemisphere forests during the past 8 ka
Lack of evidence for alternative stable states in Northern Hemisphere forests during the past 8 ka Open
With increased pressure from anthropogenic climate change, boreal forests are suspected to be approaching tipping points which could cause large-scale changes in tree cover and affect global climatic feedback. However, evidence for this pr…
View article: Comment on essd-2023-486
Comment on essd-2023-486 Open
Abstract. With rapid anthropogenic climate change future vegetation trajectories are uncertain. Climate-vegetation models can be useful for predictions but need extensive data on past vegetation for validation and improving systemic unders…
View article: Comment on essd-2023-486: consider rejection
Comment on essd-2023-486: consider rejection Open
Abstract. With rapid anthropogenic climate change future vegetation trajectories are uncertain. Climate-vegetation models can be useful for predictions but need extensive data on past vegetation for validation and improving systemic unders…
View article: Comment on essd-2023-486
Comment on essd-2023-486 Open
Abstract. With rapid anthropogenic climate change future vegetation trajectories are uncertain. Climate-vegetation models can be useful for predictions but need extensive data on past vegetation for validation and improving systemic unders…
View article: LegacyVegetation 1.0: Global reconstruction of vegetation composition and forest cover from pollen archives of the last 50 ka
LegacyVegetation 1.0: Global reconstruction of vegetation composition and forest cover from pollen archives of the last 50 ka Open
With rapid anthropogenic climate change future vegetation trajectories are uncertain. Climate-vegetation models can be useful for predictions but need extensive data on past vegetation for validation and improving systemic understanding. E…
View article: The Emergence of Low-Frequency Variability: Comparison of Historical Data and Simulations
The Emergence of Low-Frequency Variability: Comparison of Historical Data and Simulations Open
Regional climate change projections over the course of the 21st century require the accurate simulation of both anthropogenic and natural variability. The spatial patterns of natural variability are relatively well constrained on sub-decad…
View article: The quandary of detecting the signature ofclimate change in Antarctica
The quandary of detecting the signature ofclimate change in Antarctica Open
Global warming driven by human activities is expected to be accentuated in polar regions compared with the global average, an effect calledpolar amplification. Yet, for Antarctica, the amplitude of warming is still poorly constrained due t…
View article: Spatio-temporal climate fingerprint in palaeoclimate data vs models
Spatio-temporal climate fingerprint in palaeoclimate data vs models Open
Knowledge on natural climate variability is pivotal for making future climate projections. Previous studies demonstrated that centennial to millennial temperature variability is lacking in climate model simulations and that this bias is sp…
View article: Unified scaling framework for Holocene, Quaternary and Phanerozoic geochronology variability
Unified scaling framework for Holocene, Quaternary and Phanerozoic geochronology variability Open
With few exceptions, paleodata are irregularly sampled; this poses numerous challenges for the statistical characterization of paleoindicators, this includes the indicators needed to understand the climate and macroevolution.  The key…
View article: Biome‐ and timescale‐dependence of Holocene vegetation variability in the Northern Hemisphere
Biome‐ and timescale‐dependence of Holocene vegetation variability in the Northern Hemisphere Open
Global climatic changes expected in the next centuries are likely to cause unparalleled vegetation disturbances, which in turn impact ecosystem services. To assess the significance of disturbances, it is necessary to characterize and under…
View article: Regional pollen-based Holocene temperature and precipitation patterns depart from the Northern Hemisphere mean trends
Regional pollen-based Holocene temperature and precipitation patterns depart from the Northern Hemisphere mean trends Open
A mismatch between model- and proxy-based Holocene climate change, known as the “Holocene conundrum”, may partially originate from the poor spatial coverage of climate reconstructions in, for example, Asia, limiting the number of grid cell…
View article: LegacyClimate 1.0: a dataset of pollen-based climate reconstructions from 2594 Northern Hemisphere sites covering the last 30 kyr and beyond
LegacyClimate 1.0: a dataset of pollen-based climate reconstructions from 2594 Northern Hemisphere sites covering the last 30 kyr and beyond Open
Here we describe LegacyClimate 1.0, a dataset of the reconstruction of the mean July temperature (TJuly), mean annual temperature (Tann), and annual precipitation (Pann) from 2594 fossil pollen records from the Northern Hemisphere, spannin…
View article: LegacyClimate 1.0: a dataset of pollen-based climate reconstructions from 2594 Northern Hemisphere sites covering the last 30 kyr and beyond
LegacyClimate 1.0: a dataset of pollen-based climate reconstructions from 2594 Northern Hemisphere sites covering the last 30 kyr and beyond Open
This repository consists of code to run the climate reconstruction from fossil pollen data for an example site based on the R-rioja package. The input data includes harmonized open-access modern and fossil pollen datasets so that customize…
View article: LegacyClimate 1.0: a dataset of pollen-based climate reconstructions from 2594 Northern Hemisphere sites covering the last 30 kyr and beyond
LegacyClimate 1.0: a dataset of pollen-based climate reconstructions from 2594 Northern Hemisphere sites covering the last 30 kyr and beyond Open
This repository consists of code to run the climate reconstruction from fossil pollen data for an example site based on the R-rioja package. The input data includes harmonized open-access modern and fossil pollen datasets so that customize…
View article: Comment on cp-2022-89
Comment on cp-2022-89 Open
Abstract. Noise in Holocene paleoclimate reconstructions can hamper detection of centennial-to-millennial climate variations and diagnoses of the dynamics involved. This paper uses multiple ensembles of reconstructions to separate signal a…
View article: Do tree-rings match the low-frequency patterns represented in climate models?
Do tree-rings match the low-frequency patterns represented in climate models? Open
Whether tree-rings faithfully archive the low-frequency variability (LFV) in climate remains debated. In theory, trees are fundamentally limited by being relatively short-lived and therefore unable to capture variations in the climate that…
View article: Emergence of Low-Frequency Temperature Variability in Instrumental Data and Model Simulations
Emergence of Low-Frequency Temperature Variability in Instrumental Data and Model Simulations Open
The amplitude and spatial distribution of low-frequency natural variability is determinant for regional climate projections, but it is still poorly understood.  In a previous study, pollen-based temperature reconstructions were u…
View article: Comment on egusphere-2022-914
Comment on egusphere-2022-914 Open
Abstract. The regional impacts of multiple possible future emission scenarios can be estimated by combining a few Earth System Model (ESM) simulations with a linear pattern scaling model such as MESMER which uses the pattern of local tempe…