A scientific report has stated that claims that the Arctic Ocean is almost completely, and permanently, ice-free is an oversimplified statement. The report came from the scientists at the Scripps Institution of Oceanography. Till Wagner and Ian Eisenman, the research scientists, believe they have resolved the debate over the irreversible loss of Arctic sea ice.
In 2007, Arctic sea ice loss was at a record minimum. The idea that there is a sea ice tipping point has been a topic of public debate around the notion that climate change is man-made. The idea of irreversible Arctic sea ice loss is backed by mathematical models of the physical process, which scientists thought were driving the changes in the ice. The models predicted that an increase in global warming would create a waterfall of melting that would not stop until there is no more ice to melt.
The research produced by Wagner and Eisenman was co-funded by the Office of Naval Research (ONR) and the National Science Foundation. The report backs the Arctic Roadmap, the goals of the U.S. Navy, to assess changes in the Arctic Ocean and determine the challenges of national security. The assessment is all for future naval operations as the strategic Arctic region gains accessibility.
The ONR’s interest in the changes in the Arctic Ocean and the Arctic sea ice go beyond strategic processes. It is understood that the dynamics of sea ice are critical to the changing environment. The Navy’s physical models do not determine the process of controlling ice formation and ice melting. ONR is experimenting with sea ice, acoustics, the open water process and circulation.
Scientists who have been using global climate models (GCMs), which are more detailed and involved than process models, did find that sea loss was a response to higher greenhouse gases. Computer simulations showed that this is reversible when there is a reduction in greenhouse gases. However, it could not be determined which model was correct, therefore, it was not clear whether a tipping point was an actual threat.
This debate is settled in the study, performed by Wagner and Eisenman, that will be published in the Journal of Climate and titled How Climate Model Complexity Influences Sea Ice Stability. The team put together a model that was able to find the missing links in the process models and the GCMs. This was used to assimilate what actually causes sea ice tipping points to happen in some models, but not others.
Eisenman said there were two key physical processes, often overlooked in other process models previously used, that were essential to determining if the Arctic sea ice loss was reversible. One physical process shows how heat travels from the warmest places to the coldest places. The other physical process has to do with the seasonal cycle. These two factors were left out of other models and studies, so they arrived to a tipping point that did not correspond with reality.
Wagner stated that their study shows that the evidence for sea ice tipping, when the additional processes are considered and added to the equation, do not hold up. The Arctic summer sea ice will not be devoured. Therefore, according to Wagner and Eisenman’s results, if all the Arctic sea ice is melted by global warming, it is possible to get it back if the planet is cooled down enough.
By Jeanette Smith
Photo courtesy of Patrick Shyu – Creativecommons Flickr License