are thinning faster than previously thought, so fast that if the current rate continues, several of these massive floating pieces of ice could disappear within a century, according to new research out of at the University of California, San Diego. The scientists analyzed 18 years worth of satellite data — a longer, more continuous amount of time than any previous studies of this region — to get their results.

“West Antarctic losses increased by 70 percent in the last decade, and earlier volume gain by East Antarctic ice shelves ceased. In the Amundsen and Bellingshausen regions, some ice shelves have lost up to 18 percent of their thickness in less than two decades,” the researchers wrote in , published Wednesday, Mar. 25 in the journal Science.

Let’s break down that summary, piece by piece.

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First, it’s important to understand that the Antarctic ice shelf are divided into two regions or parts, the East Antarctic ice shelves and the West Antarctic ice shelves. For the first half of the study period, the mass of ice in the East actually grew, possibly due to increased precipitation rates, lead researcher Fernando S. Paolo of Scripps, explained to weather.com. At the same time, ice in the West was thinning. Yet the two balanced each other out so there were no significant losses or gains in ice.

During the second decade in the research period, however, something changed, and both East and West ice began losing volume, the West at an alarmingly speedy rate, in two places in particular, the Amundsen and Bellingshausen regions. “These ice shelves,” Paolo said, “they have changed 18 percent, they have lost 18 percent of their average volume.”

Though that may not sound significant, Paolo clarifies why it actually is. “Some of these ice shelves, they have existed for thousands of years,” he said. According to the National Snow and Ice Data Center (NSIDC), in places protected from the elements, these can “survive for thousands of years, bolstered by the rock of peninsulas and islands.” So given that the rate of change projected by Paolo and colleagues means some of these disappearing in a fraction of that time, “now we realize that is a substantial change,” he said.

There’s the potential for sea levels to rise as these shelves thin and melt, though because they are already in the water, the relationship is a little complex. The shelves act like a sort of barrier, preventing ice streams and glaciers from ending up in the ocean, notes NSIDC. “If an ice shelf collapses … the glaciers that fed into the ice shelf speed up, flowing more quickly out to sea.” That, in turn, ups water levels.

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Paolo said he and his colleagues are trying to “understand what is causing the current changes that we see. That’s the only way we can improve our prediction tools,” he noted. To that end, the researchers are looking at the impact of environmental variables such as El Nino in the tropical Pacific, sea surface pressure, sea surface winds and ocean temperatures on the ice shelves. “We try to find these correlations,” Paolo said.

For Paolo, at least, it’s a labor of love; the scientist has been interested in Antarctica since high school. “I love going there and seeing the Antarctic environment,” he said. “That was a defining moment.”

The paper, “,” ran online in Science on Wednesday, Mar. 25, 2015.

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Pedersen Glacier is photographed from Aialik Bay in Alaska in 1909. (USGS/ U.S. Grant)