Sensitivity of the dynamics of Pine Island Glacier, West Antarctica, to climate forcing for the next 50 years

Abstract

Abstract. Pine Island Glacier, a major contributor to sea level rise in West Antarctica, has been undergoing significant changes over the last few decades. Here, we employ a three-dimensional, higher-order model to simulate its evolution over the next 50 yr in response to changes in its surface mass balance, the position of its calving front and oceaninduced ice shelf melting. Simulations show that the largest climatic impact on ice dynamics is the rate of ice shelf melting, which rapidly affects the glacier speed over several hundreds of kilometers upstream of the grounding line. Our simulations show that the speedup observed in the 1990s and 2000s is consistent with an increase in sub-ice-shelf melting. According to our modeling results, even if the grounding line stabilizes for a few decades, we find that the glacier reaction can continue for several decades longer. Furthermore, Pine Island Glacier will continue to change rapidly over the coming decades and remain a major contributor to sea level rise, even if ocean-induced melting is reduced.

Reducing uncertainties in projections of Antarctic ice mass loss

“…However, this comparison remains qualitative as most of the models we compare use different setups that are certainly responsible for a part of the spread between models. Figure 4 presents the evolution of the cumulated contribution of PIG drainage basin to SLR for the period 2000-2050 according to the SeaRISE M3 experiment and according to Joughin et al (2010), Favier et al (2014) and Seroussi et al (2014). As mentioned above, estimations from SeaRISE range from a very limited retreat of the grounded line (e.g., Fig.…”

“…Pine Island Glacier (Joughin et al, 2010;Favier et al, 2014;Seroussi et al, 2014) and Thwaites Glacier (Joughin et al, 2014) in particular have shown considerable contemporary grounding line retreat and thinning . Joughin et al (2010) present a first comprehensive modeling of Pine Island Glacier (PIG) based on a SSA model and using assimilation methods for initialization.…”

“…In this paper, we assess the origin of uncertainty in recent ice sheet model projections of Antarctic sea-level contribution for PIG, based on SeaRISE and results due to Favier et al (2014), Seroussi et al (2014) and Joughin et al (2010), guided by MISMIP and MISMIP3d. We further evaluate the potential bias introduced by models that are limited by marine ice sheet physics and reassess SLR projections for Pine Island Glacier based on MISMIP-tested models.…”

“…In view of the small SeaRISE sample, we extended the sample with recent regional studies (basin-scale), focused on Pine Island Glacier (Joughin et al, 2010;Favier et al, 2014;Seroussi et al, 2014). Since the most significant changes in grounding line position and mass balance are currently observed over PIG , this drainage basin appears to be the most appropriate region to evaluate the impact of model physics/numerics on SLR projecwww.the-cryosphere.net/9/2043/2015/ The Cryosphere, 9, 2043-2055, 2015…”

“…The study finally estimates the contribution of PIG to SLR over the next 20 years ranging from 3.5 to 10 mm. Finally, Seroussi et al (2014) use a higher-order model over PIG to simulate its dynamical response to marine forcing over the next 50 years using a higher-order model, with spatial resolutions down to 500 m at the grounding line. This particular model did not perform the MISMIP experiments, but as with the Joughin et al (2014) model, physics and numerical implementation are conform to MISMIP and MISMIP3d recommendations.…”