Climate changes Earth’s rotation

If you love your planet – and I think you should, then the most beautiful image ever produced must be the photograph of the Earth taken from space by NASA a few years ago. Never before could anyone living on this planet see the Earth from this perspective and get a sense of its enormity. And its loneliness.

We see a luminous marbled sphere the colour of a milky blue sky that seems to glow with an interior light. We have never before seen our planet from space. Never seen the Earth as an alien might see us. Never seen the Earth as a whole fully-formed planet and not just a flattened landscape from a point on the surface where the slightly curved horizon is as far as we can see.

What is striking is how clean this planet appears to be. Pale blue seems cleaner even than colourless white. It suggests translucent water in its purest form and a habitat welcoming life. The Earth seems bathed in pure water. This luminous perfectly-formed planet shines out against the deep blue-black of the empty silent space in which the slowly spinning planet effortlessly moves.

You wouldn’t think it would be so easy to physically disrupt the movement of such a massive planet. Weighing in at about 6 trillion billion tons and travelling around the sun at more than 100 000 km an hour, planet Earth has some serious momentum going for it. And yet it wobbles. It wobbles ever so slightly around its axis—the result of some cataclysmic impacts with several huge meteors that smashed into the Earth thousands maybe millions of years ago with enough force to bang the planet slightly off its axis. So planet Earth is not immovable. That enormous angular momentum can be smacked with such force by an incoming meteor that the planet is knocked off its axis to a tiny but measurable degree.

But we humans have a way of being much more devious. A recent report from NASA’s Jet Propulsion Lab has found that the melting of the ice sheets of Greenland and Antarctica is having a measurable effect on the Earth’s axis of rotation. Greenland is losing 272 billion tons of ice a year. Antarctica almost as much. A tiny fraction of the mass of the planet to be sure, but enough of a change in the distribution of mass around the axis of rotation so as to slightly change the way Earth wobbles around its axis. Called the polar motion, it has been measured for over a century and during that time the true north pole has been shifting slightly to wards Canada. In the last few years it has reversed course and is now moving towards the British Isles. An expert at the Center for Space Research at the University of Texas is quoted as saying that there is nothing to worry about: “It’s just another interesting effect of climate change.”

Nothing to worry about? Seriously? Nothing to worry about? Where have we heard that one before?

Remember Captain Edward Smith? He was the captain of the Titanic. A massive unsinkable ship. “Don’t worry”, he smiled as the compartments below deck started to flood. “It’s unsinkable. It says so right here in the user manual.” “Nothing to worry about. Trust me.”

But isn’t this an astonishing and frightening first? How many times before, in the billion-year history of this pale blue planet has homo sapiens, or any of those Neanderthal species that came before, ever come close to applying enough force, or done enough damage, to move the Earth off its orbit? Because that’s what we have done. Shifting the distribution of mass about the axis of planet Earth will change its orbit around the sun. Not by much, but it’s the not the measurement that counts. Don’t listen to the physicists who tell you the change is infinitesimal. Ask them if they can measure it. You will see them hesitate, because these days they can measure everything down to infinitesimal and beyond. So we humans that populate this planet, because of the way we use our planet, damage our planet–the way we rip it apart, fracture it, and burn the carbon that was laid down millions of years ago by primeval forests, have succeeded in doing the impossible.

We have changed the way the Earth moves around the sun.

We are going down a path that is unknowable. That leads to a place that no-one can yet imagine. It may be benign—a change of seasons, unusual weather; nothing serious. But it may be inconceivably worse. Only time will tell. But seriously, are we just going to sit back and watch what happens?

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