Missions

The general objective is to investigate the diversity of the warm periods (interglacials) of the past 500 ka using a combined data-model approach. The selected candidate will contribute to the work currently undertaken as part of the MOPGA HOTCLIM project (2020-2026).

Activités

Past warm intervals (interglacials) of the Quaternary represent a series of natural experiments to understand the sensitivity of the climate system to its boundary conditions i.e. the external orbital forcing, atmospheric greenhouse gas concentrations and continental ice sheet volume. In particular, the interglacials of the last 450 thousands of years (ka hereafter) are relevant in the context of current and future global climate change as they are characterized by a warming amplitude in Antarctica, comparable to that simulated for the end of the century.
The boundary conditions varied a lot from one interglacial to another with consequent effects on the recorded climate changes in natural archives. Indeed, paleoclimate records reveal a large interglacial diversity in terms of their intensity, shape and duration. The occurrence of interglacials with differing characteristics is an intriguing aspect of glacial-interglacial cycles that the 'ice age' theory does not account for. Despite significant progress made over recent decades in developing continuous records from climate archives and climate models with different degrees of complexity to test possible mechanisms, the link between interglacial properties, orbital forcing, atmospheric CO2 and resultant feedbacks remains unexplained. Two of the main limitations are that:
-A comprehensive view of the forcings, the climate system response and the impacts at larger scales requires to build paleodata data syntheses providing a spatio-temporal view of interglacial climate at multi-millennial scale. However, such data syntheses are still lacking beyond the Last Interglacial referred also to as Marine Isotope Stage (MIS) 5e, ~129-115 ka).
-The modelling of interglacials and the comparison with paleodata are key (1) to test with physics-based tools climate forcing and feedbacks hypothesized from the data and (2) to evaluate how well Earth System Models also used for future projections, simulate warm climates. However, the realism of Earth System model simulations investigating the diversity of interglacials has not been fully tested yet as model-data comparisons focus mainly on the two most recent interglacials.
As part of the HOTCLIM project, work is on-going to provide the first multi-millennial-scale spatio-temporal climate data syntheses over Marine Isotopic Stage (MIS) 7 (~260-190 ka) and MIS 9 (~350-300 ka). Those two intervals are of particular interest: the MIS 7 warmth intensity is relatively weak while the northern hemisphere summer insolation forcing is one of the strongest in the past 800 ka. As for MIS 9, it is characterized by the highest atmospheric CO2 levels over the last 800 ka.
Hence, we are looking for a postdoctoral researcher who will investigate past interglacial diversity using MIS 7 and MIS 9 as study cases to be compared also with MIS 5e. To do so, she/he will:
* Build on the individual MIS 9, MIS 7 and MIS 5e climate syntheses to compare climate changes at regional scale between these three different interglacial periods as recorded in natural archives;
* Compile existing transient and equilibrium climate simulations from different Earth System models on MIS 7 and MIS 9 and identify key modeled climatic patterns during these two interglacials;
* Lead a comparison between (1) MIS 9, 7 and 5e climate data and (2) outputs from existing and new simulations.
The selected candidate is expected to write scientific articles, to present results in international conferences and to be involved in the ICE3 and IGE activities (group meetings, seminars, ...).

Compétences

The selection will be based on the following scientific and technical criteria:
-Good understanding of the climate system and climate changes during 2 Ma;
-Demonstrated experience in interpreting paleoclimatic dataset;
-Demonstrated experience in climate data analysis;
-Demonstrated experience in programming tools;
-Demonstrated experience in scientific writing;
-Excellent communication skills in English, both oral and written;
-Ability to work as part of a team.

Contexte de travail

The selected candidate will be affected at the Institute for Environmental Geosciences (IGE), in Grenoble, in the French Alps. This is a public research institute under the affiliation of CNRS, IRD, University Grenoble Alpes, and Grenoble-INP. It brings together about 250 people, including 150 permanent members (researchers, teacher-researchers, engineers) and about a hundred contractual agents (doctoral students, postdocs, engineers and technicians). The institute also welcomes several dozen trainees and scientific visitors every year. It is spread over two sites of the Grenoble University Campus that are 5 minutes away from each other. IGE is one of the main institutes within the Observatoire des Sciences de l'Univers de Grenoble (OSUG) which is a federative structure of INSU.
The selected candidate will join the ICE3 team which carries out research that aims at a better understanding of the past climatic and environmental variations, either of natural origin or due to human activities and will be supervised by Emilie Capron.
There will be strong interactions with Nathaëlle Bouttes (Laboratoire des Sciences du Climat et de l'Environnement) who is an expert on climate modelling.

Contraintes et risques

The research will be carried out in either French or English, however it is expected that the non-French speaking candidate will strive to learn the basics of French in order to facilitate communication and integration into the laboratory.