Planet Earth is moving towards days of more than 24 hours, but why?
We already know that the impact of human activity on the planet is considerable, both on biodiversity and on the climate, but new research shows that it also has an impact on the rotation of the Earth around the sun. Global warming, of which Man is the main actor, causes the lengthening of our days. This alarming observation is the result ofA recent study published in PNASan American multidisciplinary scientific journal.
While this remains invisible to the naked eye for us, scientists have observed that the Earth’s rotation speed is becoming slower and slower. In the future, the Earth will no longer take 24 hours to complete a full rotation, but rather one day, but more. One of the reasons for this “loss of speed” of the Earth is the gradual disappearance of glaciers. The melting of ice in Greenland and Antarctica has been accelerating for 30 years. This phenomenon causes methane to be released into the atmosphere, aggravating climate change. It also causes sea levels to rise, so much so that between the end of the last century and the beginning of the next, sea levels could have risen by 15 centimetres. This has the direct consequence of changing the mass of the planet and creating a greater concentration of mass at the equator.
“The initially fast rotation becomes slower because the masses move away from the axis of rotation, increasing the physical inertia.” “It’s like when a figure skater does a pirouette, first holding her arms close to her body and then stretching them out,” explains Benedikt Soja, co-author of the study and researcher at the ETH Zurich.
So we are heading straight for longer days. Since 1900, the climate has lengthened the length of a day by about 0.8 milliseconds, but the findings of the researchers behind the study show that global warming alone could triple this lengthening within a hundred years. It’s tiny, we might say, it won’t change anything. But this invisible phenomenon already poses serious problems. Problems that impact both our everyday lives and a whole host of technologies ranging from GPS to probes sent outside our solar system.
Still, for the moment, the slowing of the Earth’s rotation and the lengthening of days are in every way less worrying than the other problems caused by rising sea levels. Already this year, some of the inhabitants of the island of Gardi Sugdub, in the San Blas archipelago, have had to leave their homes because of rising sea levels, making them Panama’s first climate refugees.