Description du projet
Estimations quantitatives du comportement de la calotte glaciaire
L’océan Antarctique absorbe jusqu’à 75 % de l’excès de chaleur et 40 % des émissions de dioxyde de carbone générées par l’homme et absorbées par les océans. D’autre part, l’absorption de la chaleur observée et le réchauffement associé de l’océan Antarctique a un impact déstabilisant sur les calottes glaciaires de Antarctique. Cependant, on sait peu de choses sur la façon dont ces processus se développeront lors du réchauffement climatique à venir. Ces informations seront utiles pour prédire la fonte de la calotte glaciaire et les scénarios d’élévation du niveau de la mer à l’échelle mondiale. Dans ce contexte, le projet OceaNice financé par l’UE portera sur la compréhension parfaite et sur les estimations quantitatives des changements océanographiques produits à proximité de la couche glacée et des conséquences de la fonte de la calotte glaciaire observée lors des derniers épisodes climatiques chauds. Il sera ainsi possible de prévoir avec précision la future élévation du niveau de la mer.
Objectif
Antarctic ice sheets are destabilizing because Southern Ocean warming causes basal melt. It is unknown how these processes will develop during future climate warming, which creates an inability to project ice sheet melt and thus global sea level rise scenarios into the future. Studying past geologic episodes, during which atmospheric carbon dioxide levels (CO2) were similar to those projected for this century and beyond, is the only way to achieve mechanistic understanding of long-term ice sheet- and ocean dynamics in warm climates. Past ocean-induced ice sheet melt is not resolved because of a paucity of quantitative proxies for past ice-proximal oceanographic conditions: sea ice, upwelling of warm water and latitudinal temperature gradients. This hampers accurate projections of future ice sheet melt and sea level rise.
OceaNice will provide an integral understanding of the role of oceanography in ice sheet behavior during past warm climates, as analogy to the future. I will quantify past sea ice, upwelling of warm water and latitudinal temperature gradients in three steps:
1. Calibrate newly developed dinoflagellate cyst and biomarker proxies for past oceanographic conditions to glacial-interglacial oceanographic changes. This yields quantitative tools for application further back in time.
2. Apply these to two past warm climate states, during which CO2 was comparable to that of the future under strong and moderate fossil fuel emission mitigation scenarios.
3. Interpolate between new reconstructions using high-resolution ocean circulation modelling for circum-Antarctic quantification of past oceanographic conditions, which will be implemented into new ice sheet model simulations.
The groundbreaking new insights will deliver mechanistic understanding and quantitative estimates of ice-proximal oceanographic changes and consequent ice sheet melt during past warm climates, which will finally allow accurate future sea level rise projections given anticipated warming.
Champ scientifique
Programme(s)
Thème(s)
Régime de financement
ERC-STG - Starting GrantInstitution d’accueil
3584 CS Utrecht
Pays-Bas