Due to the strong warming of the Southern Ocean, glaciers at the edge of the Antarctic continent are rapidly melting from below. This destabilizes inland ice masses, causing them to collapse. The loss of Antarctic land ice directly contributes to sea level rise. A recent study shows that the collapse of two Antarctic glaciers is inevitable, leading to a global sea level rise of at least 1 meter, and about 1.25 meters along the Dutch coast.
Antarctic glaciers are melting
It has long been known that two large glaciers in West Antarctica, Thwaites and Pine Island, are very sensitive to warming seawater and are currently melting rapidly (figure 1). This is caused by the fact that a large part of these glaciers lies below current sea level and thus easily comes into contact with warming ocean water. As these glaciers retreat, they enter deeper water, making them extremely sensitive to ocean warming. This is concerning because both glaciers contain enough ice to raise global sea levels by more than one meter if they were to melt completely.
More accurate modeling of the Antarctic Ice Sheet
Future changes to the Antarctic Ice Sheet are determined using computer calculations of ice melting, ice flows, and snowfall on the ice sheet. Current observed ice thickness changes are one of the main sources of uncertainty. In a recent study from Utrecht University (IMAU), a new technique is applied to correctly incorporate these ice thickness changes, focusing especially on the two climate-sensitive glaciers mentioned. This allows future developments for various climate scenarios (levels of warming) to be calculated much more accurately than before.
Melting can no longer be stopped
The results of this study paint a very worrying picture. It appears that even if warming were to abruptly stop now (an extremely optimistic/unrealistic scenario), these two glaciers will largely disappear over time (figure 2), first gradually, but ultimately culminating in a rapid collapse (figure 3). This means that global sea level will inevitably rise by at least 1 meter (1.25 m for the Netherlands). The study also shows that this collapse will take at least 300 years. Model calculations for a (more realistic) further warming climate indicate that this period shortens by 25-100 years, and that the associated sea level rise by 2100 doubles. In other words, the collapse of these two glaciers is inevitable, but the timeframe depends on the degree of warming caused by greenhouse gas emissions.
Sea level will inevitably rise by 1.25 meters
This study shows that correctly implementing current observed ice thickness changes in calculations significantly increases the loss of Antarctic land ice and the associated sea level rise, and that just by the disappearance of the two mentioned Antarctic glaciers, the world will inevitably face at least 1 meter of sea level rise (1.25 meters for the Netherlands).
