Underwater melting of tidewater glaciers is occurring much faster than was predicted, said researchers. They used a new approach to directly measure submarine melt, which could enhance projections of sea level changes.
The findings published in the journal Science could lead to improved forecasting of climate-driven sea level rise, based on a new method developed by the researchers.
"Our study shows that the prevailing theory significantly underestimates melt rates. These results suggest a stronger coupling between the ocean and glacier than previously expected and our work provides a path forward to improve our understanding of how the ocean impacts glaciers," Jackson said.
melt rates are significantly higher than expected across the whole underwater face of the glacier -- in some places 100 times higher than theory would predict.
"We also found, as expected but never shown, that melt rates are higher in summer than in spring, and that variations in melt rates across the terminus cause overcutting and undercutting," Jackson said.
While the study focused on one tidewater glacier, the new approach should be useful to researchers who study melting at other tidewater glaciers around the world, which would help to improve projections of global sea level rise.
"Future sea level rise is primarily determined by how much ice is stored in these ice sheets," Sutherland said. "We are focusing on the ocean-ice interfaces, because that's where the extra melt and ice is coming from that controls how fast ice is lost. To improve the modeling, we have to know more about where melting occurs and the feedbacks involved."
According to the researchers, the results also align with several recent studies of other glaciers that have indirectly suggested that theory under-predicts melting.