Faster global warming predicted, with new Antarctic study

Climate Central By Mikayla Mace, Arizona Daily Star 10 June 18

A group of scientists, including one from the University of Arizona, has new findings suggesting Antarctica’s Southern Ocean — long known to play an integral role in climate change — may not be absorbing as much pollution as previously thought.

To reach their contradictory conclusion, the team used state-of-the-art sensors to collect more data on the Southern Ocean than ever before, including during the perilous winter months that previously made the research difficult if not impossible.The old belief was the ocean pulled about 13 percent of the world’s carbon dioxide — a greenhouse gas that contributes to climate change — out of the atmosphere, helping put the brakes on rising global temperatures.

Some oceanographers suspect that less CO2 is being absorbed because the westerlies — the winds that ring the southernmost continent — are tightening like a noose. As these powerful winds get more concentrated, they dig at the water, pushing it out and away.

Water from below rises to take its place, dragging up decaying muck made of carbon from deep in the ocean that can then either be released into the atmosphere in the form of CO2 or slow the rate that CO2 is absorbed by the water. Either way, it’s not good.

The Southern Ocean is far away, but “for Arizona, this is what matters,” said Joellen Russell, the University of Arizona oceanographer and co-author on the paper revealing these findings. “We don’t see the Southern Ocean, and yet it has reached out the icy hand.”

Oceans, rivers, lakes and vegetation can moderate extreme changes in temperature. Southern Arizona has no such buffers, leaving us vulnerable as average global temperatures march upward.

“Everybody asks, ‘Why are you at the UA?’” Russell said about studying the Southern Ocean from the desert at the University of Arizona. She said the research is important to Arizona and the university supports her work.

…….. scientists know less about the Southern Ocean than the rest of the world’s oceans. What they do know is mostly limited to surface CO2 levels in the summer, when it’s safer to take measurements by ships with researchers aboard. Shipboard sensors that directly measure CO2 are the accepted scientific standard in these types of studies.

Understanding CO2 levels within the air, land and sea and how it is exchanged between the three is necessary for making more accurate future climate predictions.

To fill the gap in knowledge, Russell and her team have deployed an array of cylindrical tanks, called floats, that collect data on carbon and more in the Southern Ocean year-round. Russell leads the modeling component of this project called Southern Ocean Carbon and Climate Observations and Modeling, or SOCCOM.

The floats drift 1,000 meters below the surface. Every 10 days, they plunge a thousand meters deeper, then bob up to the surface before returning to their original depth.

For three years, 35 floats equipped with state-of-the-art sensors the size of a coffee cup have been collecting data along the way and beaming it back to the researchers, like Russell in Tucson. Within hours, the data is freely available online.

They measure ocean acidity, or pH, and other metrics to understand the biogeochemistry of the elusive ocean, but not without controversy.

Making a splash

Alison Gray, an oceanographer at the University of Washington, is the lead author on the study. She said there are two reasons the study may contradict what has previously been thought of about the Southern Ocean: The lack of winter-time observations at the ocean by other researchers and the fact that ocean carbon levels might vary throughout the year.

So while SOCCOM is making it possible to get more data than ever before, others question her nontraditional methods. ………http://www.climatecentral.org/news/antarctic-ocean-discovery-warns-of-faster-global-warming-21865