Scientists May Have Underestimated Global Sea Level Rise

That may not be as bad as it sounds, though.

Getty Images / Mark Wilson

The rise in global sea levels has been one of the most tangible results of climate change, and it might be worse than we thought. A study published September 19 in Geophysical Research Letters explained that because the areas measured had lower than average rises, historical data may have leaned more conservative in its findings.

“It’s not that there’s something wrong with the instruments or the data,” said Dr. Philip Thompson, associate director of the University of Hawaii Sea Level Center, in an interview with published Monday. Thompson’s team worked with researchers at Old Dominion University and the NASA Jet Propulsion Laboratory. “For a variety of reasons, sea level does not change at the same pace everywhere at the same time. As it turns out, our best historical sea level records tend to be located where past sea level rise was most likely less than the true global average.”

It sounds like a slip-up, but it’s actually good news for scientific accuracy. The research means scientists can say with more certainty that the global sea rise level was not less than 14 centimeters (5.5 inches), and was more likely to be around 17 centimeters (6.69 inches). Ice melt fingerprints, used during the 20th century to measure level changes, was largely concentrated in the northern hemisphere, which this new research shows was a lower figure compared to the rest of the world.

Thompson et al/

“This is really important, because it is possible that certain melt fingerprints or the influence of wind on ocean circulation might cause us to overestimate past sea level rise,” Thompson told, “but these results suggest that is not likely and allow us to establish the minimum amount of global sea level rose that could have occurred during the last century.”

The rising sea level is of serious concern to coastal communities. Six Pacific islands have already disappeared due to the rising levels, and there are concerns about the rising damage costs incurred by local governments. Measuring the changes taking place is of vital importance to these communities, making the team’s research a crucial step in the fight against rising sea levels.

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