Rising Seas Slow the Planet’s Yearly Journey [View all]

[marmar]

This Creative Commons-licensed piece first appeared at Climate News Network.


LONDON—Scientists may be about to resolve one of the trickiest – and least obvious – questions of climate change: its effect on the rotation of the planet, and therefore on the length of the day.

That doesn’t mean scientists have an answer, and if they get one, it is likely to be measured in units of time that are vanishingly small. But even if the answer is insignificant, the attempt to resolve the question is a measure of the intricacy, impact and reach of global warming as a consequence of the human combustion of fossil fuels: it even affects the axis of the planet, and it changes our days.

Jerry Mitrovica, a planetary scientist at Harvard University, and colleagues report in the journal Science Advances that they have managed to make a connection between global sea level rises of the past and the rotation of the Earth on its year-long journey around the Sun.

More precisely, they have addressed a 13-year-old puzzle known as Munk’s enigma. This study raised a simple question that cannot be answered simply: if changes on the Earth’s surface slow its rotation, surely it should be possible to detect the contribution of sea level rise?

Almost anything can affect the rotation of the planet: the 2011 Tohoku earthquake and tsunami shortened the day by 1.8 millionths of a second, but the advance and retreat of the ice ages would also have altered the clocks, had there been any clocks at the time, and the daily ocean tides have for billions of years been making the day drag on. ................(more)

http://www.truthdig.com/report/item/rising_seas_slow_the_planets_yearly_journey_20151217