Findings of thicker sea ice near Antarctica are causing scientists to scratch their heads.
The ice paradox has already been a puzzling one for researchers who believe global warming risks melting sea ice and causing water levels to rise worldwide. Sea ice has been growing each year, bucking conventional wisdom, but now there’s even more confusing results: an underwater robot has found that sea ice is also much thicker than previously though, according to Discovery News.
Climate models suggests that sea ice should actually be shrinking due to a rise in global temperatures, largely believed to be due to humanity’s output of carbon dioxide particularly in the last century.
However, satellites observations show that the ice is actually expanding, setting new records the last three years. Antarctica’s land-based ice sheet, meanwhile, is melting.
Climate scientists hope to use measurements of sea ice thickness to help explain why the sea ice is growing. They want to know if the thickening is happening underwater as well.
The findings were published in the journal Nature Geoscience.
True to the common “tip of the iceberg” expression, most of the floating sea ice near Antarctica is underwater, making it difficult for scientists to observe and measure it from satellites. Ships and drilling aren’t reliable measurements either, because the thickest ice is extremely difficult to reach.
The research group has been using the autonomous underwater vehicle (AUV) for the past four years as a way to get at the bottom of sea ice and perform more accurate measurements. The vehicle can swim up to 100 feet deep and is equipped with an upward-facing sonar that can survey sea ice from the bottom. This gives it an advantage over drilling.
Antarctic sea ice swelled to 7.6 million square miles during the southern winter, and it is poised to break records set in 2012 and 2013. Scientists define sea ice area as portions of the ocean where ice concentration is at least 15 percent.
Meanwhile, the Arctic ice continued to shrink, dropping to 1.96 millions quare miles on Sept. 15, an area about double that of Greenland, the sixth lowest level sine tracking began in 1979.