Highlight articles

A global compilation of diatom silica oxygen isotope records from lake sediment – trends and implications for climate reconstruction

This paper presents the first comprehensive compilation of diatom oxygen isotope records in lake sediments (δ18OBSi), supported by lake basin parameters. We infer the spatial and temporal coverage of δ18OBSi records and discuss common hemispheric trends on centennial and millennial timescales. Key results are common patterns for hydrologically open lakes in Northern Hemisphere extratropical regions during the Holocene corresponding to known climatic epochs, i.e. the Holocene Thermal Maximum.

Bayesian multi-proxy reconstruction of early Eocene latitudinal temperature gradients

Large-scale palaeoclimate reconstructions are often based on sparse and unevenly sampled records, inviting potential biases. Here, we present a Bayesian hierarchical model that combines geochemical with ecological proxy data to model the latitudinal sea surface temperature gradient. Applying this model to the early Eocene climatic optimum highlights how our integrated approach can improve palaeoclimate reconstructions from datasets with limited sampling.

Toward generalized Milankovitch theory (GMT)

Despite significant progress in modelling Quaternary climate dynamics, a comprehensive theory of glacial cycles is still lacking. Here, using the results of model simulations and data analysis, I present a framework of the generalized Milankovitch theory (GMT), which further advances the concept proposed by Milutin Milankovitch over a century ago. The theory explains a number of facts which were not known during Milankovitch time’s, such as the 100 kyr periodicity of the late Quaternary.

GMT)">Read more

Rejuvenating the ocean: mean ocean radiocarbon, CO2 release, and radiocarbon budget closure across the last deglaciation

Radiocarbon is best known as a dating tool, but it also allows us to track CO2 exchange between the ocean and atmosphere. Using decades of data and novel mapping methods, we have charted the ocean’s average radiocarbon ″age” since the last Ice Age. Combined with climate model simulations, these data quantify the ocean’s role in atmospheric CO2 rise since the last Ice Age while also revealing that Earth likely received far more cosmic radiation during the last Ice Age than hitherto believed.

Late Cenozoic sea-surface-temperature evolution of the South Atlantic Ocean

We present two new sea surface temperature (SST) records in comparison with available SST records to reconstruct South Atlantic paleoceanographic evolution. Our results show a low SST gradient in the Eocene–early Oligocene due to the persistent gyral circulation. A higher SST gradient in the Middle–Late Miocene infers a stronger circumpolar current. The southern South Atlantic was the coldest region in the Southern Ocean and likely the main deep-water formation location in the Middle Miocene.

The new Kr-86 excess ice core proxy for synoptic activity: West Antarctic storminess possibly linked to Intertropical Convergence Zone (ITCZ) movement through the last deglaciation

It is unclear how different components of the global atmospheric circulation, such as the El Niño effect, respond to large-scale climate change. We present a new ice core gas proxy, called krypton-86 excess, that reflects past storminess in Antarctica. We present data from 11 ice cores that suggest the new proxy works. We present a reconstruction of changes in West Antarctic storminess over the last 24000 years and suggest these are caused by north–south movement of the tropical rain belt.

ITCZ) movement through the last deglaciation">Read more

Investigating hydroclimatic impacts of the 168–158 BCE volcanic quartet and their relevance to the Nile River basin and Egyptian history

This work is a modeling effort to investigate the hydroclimatic impacts of a volcanic “quartet” during 168-158 BCE over the Nile River basin in the context of Ancient Egypt’s Ptolemaic era (305-30 BCE). The model simulated a robust surface cooling (~1.0-1.5°C), suppressing the African monsoon (deficit of >1mm day-1 over East Africa) and agriculturally vital Nile summer flooding. Our result supports the hypothesized relation between volcanic eruptions, hydroclimatic shocks, and societal impacts.

BCE volcanic quartet and their relevance to the Nile River basin and Egyptian history">Read more

Reconstructing Holocene temperatures in time and space using paleoclimate data assimilation

To look at climate over the past 12 000 years, we reconstruct spatial temperature using natural climate archives and information from model simulations. Our results show mild global mean warmth around 6000 years ago, which differs somewhat from past reconstructions. Undiagnosed seasonal biases in the data could explain some of the observed temperature change, but this still would not explain the large difference between many reconstructions and climate models over this period.

Dynamics of the Great Oxidation Event from a 3D photochemical–climate model

In the context of understanding the 3D photochemical effect on the Earth’s oxygenation that happened around 2.4 Ga, we developed a 3D photochemical–climate model to investigate the possible impact of atmospheric circulation and the coupling between the climate and the dynamics of oxidation. We show that the diurnal, seasonal and transport variations do not bring significant changes compared to 1D models. Nevertheless, we highlight a temperature dependence for atmospheric photochemical losses.

Is it possible to estimate aerosol optical depth from historic colour paintings?

This study investigates the possibility of inferring information on aerosol optical depth from photographs of historic paintings. The idea – which has been applied in previous studies – is very interesting because it would provide an archive of the atmospheric aerosol loading covering many centuries. We show that twilight colours depend not only on the aerosol optical thickness, but also on several other parameters, making a quantitative estimate of aerosol optical depth very difficult.

Publications Highlight articles

Highlight articles

Information for

External links