Climate change alters the "clock"

The days are getting longer, scientists say. Imperceptible to humans, but the change is not negligible. Climate change, which causes the melting of the polar ice caps, slows the Earth's rotation very slightly, which increases the length of the day by a few milliseconds, a study shows. Antarctica, Greenland as well as numerous glaciers are "in the polar regions", Surendra Adhikari, co-author of the study, explained to AFP. The water resulting from the melting of glaciers under the effect of climate warming is mostly found "in the equatorial regions", and this change in the distribution of masses on the planet "has an impact on the way the Earth rotates". Which means: a little slower. "It's like when a figure skater does a pirouette, first keeping his arms close to his body, then moving them away," says Benedikt Soja, who is also a co-author of the study. The rotation, very fast at the beginning, slows down little by little. Such slower rotation slightly increases the length of a day, which has a total of 86,400 seconds. Since 2000, the rate of daylight lengthening due to climate change has increased to 1.33 milliseconds per century. And if greenhouse gas emissions continue to increase significantly, this rate could exceed 2.62 milliseconds per century by 2080 or 2100. The influence of climate change could therefore exceed the effect of the Moon, which has slowed to her turn progressively the rotation of the Earth for several billion years. "It is very surprising to note that, by the end of the 21st century, in high emission scenarios (...), it is possible that the climate will take over the contribution to a phenomenon" such as "Earth-Moon dynamics" "" commented Surendra Adhikari. While these changes may seem minimal, they have "important implications for terrestrial and space navigation," such as sending signals to distant probes, according to the researcher. According to Benedikt Soja, this study also highlights a symbolic situation: the impact of human activities on the planet is more important than we think.