Increasingly warm temperatures in West Antarctica is likely the latest sign that global warming is here to stay, according to a team of climate scientists.
In a paper released Sunday by the journal Nature Geoscience, Andrew J. Monaghan of the National Center for Atmospheric Research in Boulder, Colorado, and David H. Bromwich of Ohio State University, note that a recent analysis of the Antarctic Peninsula shows it is warming significantly faster than other regions around the world.
According to their analysis, temperatures at a research station in West Antarctica have warmed by 4.4 degrees Fahrenheit since 1958 — roughly twice the rate predicted by climate scientists. The warming “raises further concerns about the future contribution of Antarctica to sea level rise,” the report notes, as higher summer temperatures raise the risk of a surface melt of ice and snow, possibly resulting rising sea levels around the world.
The results are worrisome, according to researchers, who suggest the rising temperatures further confirm the existence of global warming and that human activities are largely to blame.
“Our results provide further evidence that climate change due to human activities (greenhouse gas emissions) is real. The expectation is that the poles will experience much larger temperature changes than elsewhere, so our results confirm this expectation for West Antarctica,” Bromwich wrote in an email to Science Recorder.
The results also suggest that Antarctica has experienced the same rapid temperature shifts as polar regions like Greenland and the Canadian Arctic, a phenomenon called polar amplification, Bromwich said. The changing temperatures have wrought havoc with local ecosystems and scientists say similar changes are likely to take place around the globe over the next one hundred years.
More importantly, the results of the study are not confined to West Antarctica. Researchers warn that the rising temperatures in Antarctica is not an isolated event. Rather, it shows global warming is widespread and far more prevalent than previously thought. Several ice shelves – thick ice blocks attached to the land at one end – have already collapsed around the Antarctic Peninsula, an area just to the north of the Byrd Research Center. Once these shelves break up, glaciers trapped behind them can slide faster into the sea, raising water levels throughout the world.
“The warming during summer is our unique contribution. If this continues, then much more ice melting at the surface will occur in the coming decades at low elevations. The ice shelves hold back the discharge of ice from West Antarctica into the ocean, and they are vulnerable to extensive surface melting,” Bromwich noted in an email to the Science Recorder. “That could significantly increase sea level rise due to West Antarctic ice loss to the ocean, and this would affect everyone that lives near the ocean.”
The study represents one of the most intensive analyses of past Antarctic temperatures. Antarctica’s Byrd Station temperature records reconstructed by the researchers find that year-by-year temperature increases accelerated there mostly in the 1980s. The research team used the data to study how the temperature has changed over the past fifty years, making it one of the most accurate studies to date.
“We analyzed regular weather observations of air temperature near the ice surface from a manned site, 1957- 1970, and from an automated year-round site, 1980-present,” wrote Bromwich. “Those observations are available to everyone without restriction.”
The scientists said there had been one instance of a widespread surface melt of West Antarctica, in 2005. “A continued rise in summer temperatures could lead to more frequent and extensive episodes of surface melting,” they wrote. The study shows West Antarctica now contributes about 0.3 mm a year to sea level rise, less than Greenland’s 0.7 mm, a statement released by Ohio State University read. The bigger East Antarctic ice sheet is less vulnerable to a thaw.
According to Bromwich, scientists will continue to study the region in the near future, although the research team does not have any definitive plans.