Understanding sea ice retreat


By Gwen Schanker, editorial columnist

Each Thursday afternoon this past month, I’ve attended a lecture on ice-ocean interaction, each led by an expert in the field. The talks, held at the Woods Hole Oceanographic Institution (WHOI), are part of a course in the Massachusetts Institute of Technology (MIT)/WHOI Joint Program in Oceanography and are open to all members of the community, including college interns like myself. The experience of attending these talks is kind of like how I imagine it must feel to stand on a piece of ice in the warming Arctic.

The lectures start with fairly intuitive information: Over time, temperatures have increased and the duration of the sea ice season has decreased – concepts I’m somewhat familiar with. They feel fairly steady. About 10 minutes in, however, it’s like my piece of ice breaks off from the rest of the sheet and floats away, leaving me to fend for myself in the changing climate. I find myself swimming in new vocabulary like bifurcation and halocline, and, as a result, struggle to keep up with what’s going on beyond the basics.

Additional education on the topic of sea ice comes from news articles on the recent reveal that sea level rise is greater today than in the past several thousand years. A study published last week, coauthored by WHOI scientist Jeff Donnelly, presented data showing that the sea level rose about 5.4 inches between 1900 and 2000. The rise is attributed to the effects of anthropogenic (human-caused) climate change, primarily temperature elevation due to increased levels of greenhouse gases. This has led to thermal expansion, melting of polar ice caps and ice retreat in parts of Greenland. Coverage of the study emphasized the link between temperature, melting ice and rising sea level, and the researchers themselves state explicitly that without anthropogenic climate change, the rise in sea level would have been much less dramatic.

Regardless, the complex information presented left readers divided, with more than a few commenters proclaiming, “Global warming is a hoax.” Despite the confidence of scientists, there’s plenty of confusion surrounding the concept of sea ice retreat and sea level rise. That’s true not only for non-believers but for students like myself as well, who are on board with the general concepts but get bogged down in the specifics. One thing that’s becoming clear through the Thursday lectures is the sheer number of factors that create the changes we’re experiencing, from El Niño oscillations to the strength of currents surrounding the Arctic and Antarctic, which cause ice in the Arctic to retreat while ice in the Antarctic expands – a seemingly contradictory phenomenon that results from the dramatic difference between these two systems.

While scientists uncover new research on sea ice every day, the significance of this doesn’t seem to be getting through to readers. Whether that’s due to excessive details or widespread denial is unclear, but it indicates a need for stronger communication. About six months ago, I wrote a column describing the challenges of science writing and how it’s easy to overdramatize a topic, leading to inaccuracy. The consequences of sea ice retreat are chilling, but as a communicator, I am faced with the challenge of telling a straightforward story while also showing exactly what’s at stake. In last Thursday’s lecture, speaker Doug Martinson of Columbia University stated that even if global warming was switched off tomorrow, the amount of heat in the deep ocean would continue to affect our climate for years to come. That’s the kind of dramatic statement that needs to get through to readers – it’s just a matter of breaking down the details in a way that doesn’t make them feel like they’re drifting off into the ocean.