U. team finds ocean storing excess heat
A research team led by Yair Rosenthal, a professor in the Institute of Marine and Coastal Sciences, came back from the Pacific Ocean with startling news.
“The ocean is warming fast, and we’re not sure why,” Rosenthal said.
The team’s research spans 10 years and suggests the ocean’s rate of heat gain, as recorded in the last 60 years, is 15 times greater than any that natural warming has shown in the last 10,000 years, said Braddock Linsley, a research professor at the Lamont-Doherty Earth Observatory at Columbia University.
“[We] know that we released a lot of heat due to fossil fuel burning and other activities, but we couldn’t find it because the [surface] temperature had not been increasing,” Rosenthal said.
The oceans have been working to buffer the ongoing rise in atmospheric temperatures, but researchers are uncertain as to how the effects of this heating will manifest, he said.
“It’s important to know that water has a high [capacity] for temperature, and so the ocean is the ultimate place where we store heat,” he said. “The atmosphere doesn’t store heat.”
The paper’s authors — Rosenthal, Linsley and Delia Oppo, a senior scientist at the Woods Hole Oceanographic Institution — traveled to Indonesia to collect sediment samples in the equatorial Pacific Ocean.
They utilized Proterozoic fossils of organisms called foraminifera that inhabit the sediment in the mid-depths of the ocean and secrete calcium carbonate shells.
Linsley stated that the shells’ magnesium concentrations serve as paleo-thermometers. Warmer waters promote higher magnesium concentrations.
“[We] were able to reconstruct Pacific intermediate water temperatures using [this] magnesium content … [to view] the last 10,000 years,” Linsley said.
Data shows that temperatures have gone through extreme fluctuations over time, he said. 1,500 years ago marked a high-temperature period known as the “Medieval Warm Period,” and 400 years ago, temperatures reached a minimum during the “Little Ice Age.”
Yet following that time, the trend reversed dramatically.
Today’s 0.32 percent increase seems small, but it is quick for only 60 years, especially when multiplied by the ocean’s volume, Linsley said.
Surface temperatures were also found to be up to 1.5 degrees less than intermediate water temperatures during some fluctuations, which is representative of water’s long-term effectiveness as a buffer.
Rosenthal noted buffer temperature changes do not happen in a human lifetime, but instead, over hundreds of years.
He said one problem with the research is that they only have information for the last 60 years instrumentally and for 400 to 10,000 years ago through the shell data. The ambiguity lies in the gap between those periods.
Current research is focused on bridging this gap with the continued use of the foraminifera, he said. The team has taken a recent voyage near Papua New Guinea for this purpose.
For now, though, the researchers have already made a few of their own hypotheses on what is causing the discrepancies.
“[This] could be … partly global warming, but it could also [be that] … the ocean is still recovering from [the Little Ice Age], whereas the surface has long recovered … since it’s hard to penetrate the deep ocean,” Yair said.
At this point, Braddock and Yair both agree that the team sees no immediate concern.
“The best-case scenario is that the ocean … is taking more heat than we thought … [and] may be slowing down the warming,” Yair said. “That’s one way to look at it, which is my optimistic way.”
Media sources, such as Science magazine and the British Broadcasting Corporation, have reported on these findings, which have been met with strong responses, especially by global warming skeptics, Braddock said.
Yet Yair insists it is still too early to make any meaning from the findings. Whether the shift is natural or not is still unknown.
“It doesn’t prove [global warming]. It just shows that [we have] a longer time scale to consider the response of the ocean,” he said. “The past few days have shown me that global warming became a religion. [Some people] believe in what they want to and discredit the others.”
Yair would rather the public relax and wait to understand what further research finds out, he said.
“This research is not driven by some political or policy agenda,” he said.
What he feels really deserves more attention is the amount of participation and progress in his field at the University.
“While there are three authors of this paper, there are a lot of Rutgers students that participated in this research, undergraduates and more, on the cruise and in the labs,” he said. “So it’s all really a community effort.”
Emily Bryk is a science teacher who worked with Yair on his research in Indonesia as a graduate student.
“Yair is a phenomenal and driven scientist, and I think that in his lab, there’s a real feeling that we were doing important work,” she said.
By his team’s strong, continuing success in research, Yair shows that research at Rutgers yields critical and promising work.
“I hope that we use these capabilities to essentially position [ourselves] as the leading institution to deal with this issue,” Yair said.