But that success is unlikely to be repeated in a more watery Arctic Ocean. The northerly sea is "already more productive [in terms of plankton] than the ice-covered ocean of the near-past," says marine biologist Victor Smetacek of the Alfred Wegener Institute for Polar and Marine Research in Germany, who helped lead those biological sequestration experiments in the Southern Ocean. But local conditions, such as a lack of nutrients and a lack of deep- and shallow-ocean water mixing, suggest that the newly open waters of the Arctic Ocean are unlikely to produce massive blooms, large fisheries or sequester CO2. "The CO2 sequestration potential of the Arctic is very limited," Smetacek says. The Arctic will not save itself.
Regardless of what the Arctic meltdown reveals, what is increasingly clear is that the computer models that scientists rely upon to make predictions have failed to capture the rapid pace of change in the far north. The problem stems from spatial resolutions that are too large—a single grid in a typical computer model encompasses 100 square kilometers—to "see" small but important features such as warm ocean water currents or ice export. And the computing capacity is insufficient to render Arctic cyclones and the role they play in breaking up the ice. "Are the models still too conservative or not?" Maslowski asks of the computer simulations that underpin future predictions. "If this present trend continues, we might be having almost no ice by the end of this decade."
Such a total summer loss of sea ice remains speculative at this point. "I wouldn't expect it to keep going straight down," NSIDC's Meier says. "The ice that is remaining may continue to stay thick even with more melt and that may be harder to get rid of. The melt could plateau." At the very least, the sea ice is likely to rebound next year, as has happened after every previous ice melt record. "That wouldn't surprise me at all," Meier says.
What may surprise, however, are the global impacts of the already far advanced loss of Arctic sea ice, particularly on the weather. "We need a few more years of empirical evidence to give a confident answer," Hansen says of the challenge of figuring out how the Arctic meltdown will affect the rest of the globe. Thanks to ever increasing greenhouse gas emissions trapping more and more heat, the world will find out this winter—and for many years to come.
"There's evidence in the paleo-climate record that the climate system is capable of changing quite rapidly," Barber notes. "We're moving into new territory and the impacts of that are unknown scientifically."