Earth's rotation slows down. Day will be 5 ms longer by 2100

Global warming has a variety of side effects. One of them is the slowdown of the Earth’s rotation, that is, an increase in the length of the day.

In 2002, the oceanographer Walter Munk published a paper in which he examined the effect of glacier melting on changes in the Earth's rotation. Theoretically, the melting of glaciers near the poles and the subsequent movement of water masses to the equator should lead to a slowdown of the planet’s rotation according to the laws of physics, but Munk came to the paradoxical conclusion that an increase in sea level of 2 mm per year for a hundred years did not affect the speed of rotation of the Earth . This conclusion in the scientific world is called the "riddle of Mank."

Scientists from Harvard University have now managed to solve this "riddle". They revealed errors in the calculations of Munk and the used historical data: for example, the sea level rose annually by 1-1.5 mm, and not by 1.5-2 mm, moreover, the oceanographer did not take into account the influence of a number of geophysical factors - for example, According to the latest theories, the Earth used to have a slightly different shape. Given all the factors, the model converges. It turns out that over the past century, Earth days have lengthened by about 1 ms.

Slowing of rotation is manifested in the results of measuring stellar coordinates relative to the Earth, as well as in the orbits of satellites, where you have to constantly make small adjustments.

In the future, the process will become more noticeable, as the melting of glaciers accelerates. Intergovernmental Panel on Climate Change (IPCC) recently published a reportwith an estimate that the increase in the oceans began to approach 3 mm per year, and the melting of glaciers will increase by 15-85%, depending on the amount of carbon dioxide emissions and the rate of forest destruction.

The increase in the world's oceans is associated not only with the melting of glaciers, but also with the thermal expansion of water.

Thus, during the 21st century, the day will increase by about 5 ms. The axis of the Earth will also move a little: the poles will shift about a centimeter.