Arctic Ocean acidification will be worse than scientists thought

June 18 (UPI) -- Climate models have been underestimating the amount of CO2 the Arctic Ocean will likely absorb during the 21st century, researchers say.

New analysis -- published this week in the journal Nature -- suggests the ocean will experience more dramatic acidification than previously anticipated.

If it wasn't for Earth's oceans, the planet would be warming much faster than it already is. That's because the oceans absorb much of the CO2 that humans are emitting into the atmosphere.

Unfortunately, all that absorbed carbon causes the ocean to become more and more acidic. Ocean acidification is a serious threat to species that built calcium carbonate skeletons and shells, including molluscs, sea urchins, starfish and corals.

Different climate models produce a wide variety of predictions for carbon uptake in the Arctic Ocean. For the study, scientists looked at a variety of climate models and isolated the variables responsible for the wide range of predictions.

The research team found a strong correlation between present-day Arctic sea surface densities and associated deep-water formation, and linking the correlation to the variability of carbon uptake predictions.

Scientists were able to narrow the range and improve the accuracy of model predictions by supplying models with more precise, up-to-date observations of sea surface density.

The new findings suggest that if human carbon emissions continue unabated, the Arctic Ocean will absorb 20 percent more CO2 over the 21st century than previously predicted.

"This leads to substantially enhanced ocean acidification, particularly between 200 and 1000 meters," study co-author Jens Terhaar, a climate scientist at the University of Bern in Switzerland, said in a news release.

If CO2 emissions aren't drastically reduced, molluscs and other shell-making marine organisms in the Arctic could be in serious trouble, researchers say.

"Our results suggest that it will be more difficult for Arctic organisms to adapt to ocean acidification than previously expected," said study co-author Lester Kwiatkowski, a climate scientist at the French National Center for Scientific Research in Paris.