The gap between simulated prediction and real-life observation in Arctic sea ice melt can be attributed to complicated internal drivers.
As an indicator of the impacts of climate change, Arctic sea ice is hard to beat. Scientists have observed the frozen polar ocean advance and retreat at this most sensitive region of the Earth over decades for insight on the potential ripple effects on assorted natural systems: global ocean circulation, surrounding habitats and ecosystems, food sources, sea levels and more.
Despite efforts to make model simulations more closely mirror actual observations of Arctic sea ice melt, however, a gap has opened: Reports on the ground indicate the ice is melting at a much faster rate than predicted by global climate models.
“Based on this phenomenon, people have different opinions,” said UC Santa Barbara climate scientist Qinghua Ding, an assistant professor in the campus’s Earth Research Institute. The consensus of the climate science community, he said, is leaning toward the idea that the discrepancy is due to flawed modeling. “It’s something like the model has some bias; it has some low sensitivity to anthropogenic forcing,” he explained.
Ding and his group disagree. In a study titled “Fingerprints of internal drivers of Arctic sea ice loss in observations and model simulations,” published in the journal Nature Geoscience, the group says the models are just fine. About 40 to 50 percent of sea ice loss over the last three decades, they argue, is attributable to significant but as yet little-understood internal drivers — among them effects that originate partially as far away as the tropics.
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Image via University of California Santa Barbara
