Global Warming: It's Now About Time

(Planet Observer/Getty/Chronicle)

Anthropogenic global warming, insist its believers, is nearly all-powerful in its ability to influence nature, but the following assertion sounds extreme:

Climate change is literally impacting time itself

The Earth’s spinning, however, has recently begun to speed up and the length of the day has started getting shorter, for reasons not fully understood. In fact, research by a geophysicist in California finds that it’s only a matter of years before an extra second will need to be subtracted from universal time, rather than added to it.

This possibility is raising concern because many computers, which have been programmed to handle an additional second, aren’t designed to lose a second, threatening to create glitches in systems governing aviation, financial markets, healthcare and more. It’s reminiscent of Y2K, when widespread bugs were feared when the calendar flipped to 2000.

The research, published last year in the science journal Nature, also finds that such a negative leap second and its potential problems are being delayed, perhaps surprisingly, by climate change. Ice that is melting around the Earth’s poles is sending water – and mass – toward the equator and consequently slowing the planet’s rotation, counteracting the faster spin.

“A second doesn’t sound like much,” said Duncan Agnew, author of the recent research and a geophysicist at Scripps Institution of Oceanography at UC San Diego, in a communication to the Chronicle. But, as he explained online: “In today's interconnected world, getting the time wrong could lead to huge problems.”

Agnew’s head-scratching projections are based on the complex and still largely unexplained physics of Earth’s rotation.

As we all know, the planet takes about 24 hours to fully spin around. But because of several factors, this timing varies ever so slightly. It’s also hard to predict. The variation was basically irrelevant until the age of computers, when milliseconds became make or break for things like stock trades and rocket launches.

Earth’s rotation, for thousands of years, has mostly slowed, the biggest driver being the changing tides that come with the gravitational tug of the moon. Currents in the planet’s outer core, which scientists are still trying to figure out, also have slowed the spin. But the core can speed up the spin, too, which may be what’s been happening recently. Additional leap seconds have become a lot less frequent the past two decades.

Since about 1990, Agnew says, the warming climate has become an additional factor, working to slow Earth’s rotation and increase the length of the day. He likens the effect of melting polar ice and the spreading meltwater on the planet’s spin to the inertia of a spinning skater: When the skater spins with her hands over her head, she rotates faster than when she extends her arms to the sides.

“Global warming has proceeded to the point that its effects are showing up in how fast the whole Earth rotates,” Agnew said. “This change in rotation has never been seen before, and this re-emphasizes that we are living in a time when unprecedented changes are happening.”

By extrapolating trends for Earth’s core and other factors affecting rotation, Agnew finds that without the melting ice, a leap second would need to be subtracted from universal time as soon as next year to account for the faster spinning planet. Now, a second won’t have to be removed until 2029, he says.

To summarize: the earth's rotation has slowed over millennia because of the moon's gravitational pull; however, the rotation has recently sped up due to (poorly understood) actions by the earth's core. Now melting ice caps are slowing the spin again. Changes in the earth's rotation add or subtract "leap"-seconds, lengthening or shortening the 24-hour day, respectively.

Even if we accept that ice sheets are melting, a strong faith in the accuracy of computer models is required to believe that the effect on the oceans will slow earth's rotation. Nevertheless, it would not be surprising if the alarmists have taken the hypothesis as proven, and that they're already trying to find a scientist who will claim that slowing earth's rotation by a second every few years is a bad thing.