1.5° target and the West Antarctic ice sheet
ZUWEISS is a BMBF funded project in which the benefits of a limitation of global warming to 1.5°C and 2°C are investigated.
The exceedance of critical temperature thresholds in the Southern Ocean can lead to an irreversible collapse of the West-Antarctic Ice Sheet. This would result in a sea level rise of several meters, influence the global ocean circulation and would therefore have consequences for the global climate. To determine the extent and the uncertainty of these effects under a given global warming (1.5°C, 2°C, business-as-usual: about 4°C), scenarios which are available worldwide as well as new simulations with the Alfred Wegener Institute Climate Model (AWI-CM) and a state-of-the-art ice sheet model are combined. Paleo climate scenarios are taken as a reference point and can be used to judge the quality of the model studies. The goal of this project is to work out what positive consequences a global warming limit of 1.5°C above the pre-industrial level which is currently discussed in the politics would have compared to less ambitious aims such as the 2°C limit or even no attempt to reduce greenhouse gas concentrations.
Publicly available simulations of the Coupled Model Intercomparison Project 5 (CMIP5) are used as driving data for the ice sheet model to study changes in the ice sheet and shelf ice over the next hundreds of years. To consider the feedback mechanisms between shelf ice, ocean, and atmosphere, coupled ice sheet – ocean – atmosphere simulations are computed for the first time in a high horizontal resolution and on climate time scales of several hundreds of years (Figure 1). The focus is on the Antarctic ice sheet but will be extended to changes in other regions (Arctic, northern and southern mid-latitudes, tropics) in the course of the project.
Özgür Gürses | Madlene Pfeiffer | Christian Rodehacke | Tido Semmler