Scientists have long believed that rising sea levels due to warming temperatures and melting glaciers could lead to an increase in extreme weather events and threaten global food supplies, and now research suggests that it could even cause days to become longer.
The phenomenon is known as “polar wander”, and as the Daily Mail explained, it is driven by the influx of meltwater from glaciers into the oceans. The movement of all this ice and water has caused the planet’s axis to migrate at a rate of one centimeter per year, and over the past century it has added one one-thousanth of a second to the length of the average day.
“Because glaciers are at high latitudes, when they melt they redistribute water from these high latitudes towards lower latitudes, and like a figure skater who moves his or her arms away from their body, this acts to slow the rotation rate of the Earth,” Harvard geophysicist Jerry Mitrovica, lead author of a new Science Advances paper detailing the findings, told Reuters.
“Imagine a figure skater who doesn’t stick their arms straight out but rather sticks one at one angle and the other out at another angle. The figure skater will begin to wobble back and forth. This is the same thing as polar motion,” he added. While the effects are “small” now, they may worsen unless more is done to combat climate change, Mitrovica noted.
Phenomenon unlikely to have any significant impact
The geophysicist and colleagues from the US, Canada, and France studied changes in the Earth’s rotation and axis against the backdrop of global sea level increases during the 1900s. Their work builds upon previous research from the same team which revealed that—as warming temperatures cause glaciers to melt—the redistribution of their mass throws off the planet’s axis.
While the rotational slowdown does not pose a danger to the planet at this time, Mitrovica told the Daily Mail that if polar ice sheet melting rates increase before the end of the century as many experts predict, than it could further slow down the Earth’s rotation—ultimately leading to significantly longer days and possibly other types of disruptions.
Or not. Mitrovica said told CNN that polar wander is unlikely to have any lasting significant impact on the planet in practical terms. However, he said that his team’s research provides a new tool to help assess the amount of melting that is taking place. As he explained, “It gives you one, simple, unpolluted measurement of what the Earth’s ice sheets and glaciers are doing.”
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Feature Image: NASA
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