Several expeditions until 2030

iQ2300 is a multi-year research initiative in Antarctica with recurring fieldwork at the German station Neumayer III and the Swedish stations Wasa and Svea, as well as two icebreaker expeditions at the beginning and end of the period 2025–2030. Researchers will collect basic data to reduce uncertainties about the future of the East Antarctic Ice Sheet. The researchers will, among other things, investigate how the ice has changed since the last ice age, how quickly the ice shelf melts in contact with the sea, whether and where surface melting can occur, how quickly the ice flows, and whether there is meltwater at the bottom. In parallel, atmospheric, Earth system, ice and sea level modelling will be carried out, taking into account new field data.

– We also want to investigate whether there is a risk that the melting could be significantly accelerated, similar to the development that has been observed for parts of the Greenland and West Antarctic ice sheets. The goal is more reliable model studies of the development of the East Antarctic ice sheet over the next few centuries, and thereby a better basis for Swedish municipalities' vulnerability analyses and long-term planning linked to sea level rise, says Arjen Stroeven, professor of physical geography at Stockholm University, and the leader of the research theme iQ2300.

Why the Riiser-Larsen Ice Shelf is in focus

The East Antarctic Ice Sheet currently contributes little to ongoing sea level rise, but this could change quickly if sea temperatures continue to rise. One key factor is the floating ice shelves, which act as a "brake" for the underlying ice sheet. Ice shelves are partly held back by the shape of the coastline and by rock crevasses beneath the ice. If climate change were to melt these floating ice shelves, which slow the underlying ice sheet, the ice would flow more rapidly towards the sea, melt, and contribute to sea level rise.

– The Riiser-Larsen Ice Shelf is such an ice shelf, and it is the fourth largest in Antarctica, with an area larger than the Netherlands. Along the edge of the ice shelf, towards the sea, there is also a relatively warm ocean current at depth, the Weddell Gyre, which, if it were to come closer to the surface, would directly affect the melting of the Riiser-Larsen Ice Shelf from below. This is therefore a very sensitive system that we believe will be able to switch from a minor impact today to a large impact in the future. Together with increasingly warmer sea temperatures and increased melting of the ice shelf, it is also snowing more heavily, suggesting the system is close to balance. We therefore want to study the system in detail before a possible threshold is crossed, at which the Riiser-Larsen Ice Shelf begins to shrink faster and its melting contributes more to sea level rise, says Arjen Stroeven.

Expedition 2025/26 – first step in a multi-year plan

During the expedition 2025/26, several efforts will be carried out to lay the foundation for studies in the coming years on the theme of iQ2300. The studies on the Riiser-Larsen Ice Shelf may be the very first to take place in this part of the ice shelf, and the first expedition truly has the character of both an expedition and an exploration.

The researchers will, among other things:

• measure the ice thickness with ground-based radar and the distance between the underside of the ice shelf and the seabed using seismic methods
• build a weather station and install a stationary ground-based radar near the boundary where the ice shelf begins to float, to monitor changes in ice thickness over the next five years
• install another stationary ground-based radar closer to the ice shelf edge and eventually verify the measurements with data from a future icebreaker expedition and an unmanned underwater vehicle
• use the results to select the best locations for a planned drilling through the ice shelf in three years

– Higher up on the ice shelf, studies are being conducted that will answer the questions of how much snow falls annually and how it is distributed over the ice shelf's surface. This is done partly through ground-based radar that can show snow layers, and partly through analyses of 5–30 metre long drill cores of hard-packed snow (firn) along a profile from the edge of the ice shelf, past the Wasa and Svea stations, up towards the polar plateau at an altitude of about 2,000 metres. The spatial picture is also supplemented by satellite measurements that need to be checked and calibrated with field data, says Arjen Stroeven.

The ambition is to deliver improved estimates of sea level rise through 2300. The results are expected to contribute to future IPCC reports and also be presented during the International Polar Year 2032–2033.