Climate Change is Altering How the Poles Drift
Ice loss driven by climate change is affecting Earth's spin axis. Continue reading →
The spin of the earth is a constant in our lives. It's quite literally why night follows day.
And while that cycle isn't going away, climate change is messing with the axis upon which our fair planet spins. Ice melting has caused a drift in polar motion, a somewhat esoteric term that tells scientists a lot about past and future climate and is crucial in GPS calculations and satellite communication.
Polar motion refers to the periodic wobble and drift of the poles. It's been observed for more than 130 years, but the process has been going on for eons driven by mass shifts inside the earth as well as ones on the surface. For decades, the north pole had been slowly drifting toward Canada, but there was a shift in the drift about 15 years ago. Now it's headed almost directly down the Greenwich Meridian (sorry Canada no pole for you, eh).
"Since about 2000, there has been a dramatic shift in this general direction," Surendra Adhikari, a researcher at NASA's Jet Propulsion Laboratory, said. "It is due to climate change without a doubt. It's related to ice sheets, in particular the Greenland ice sheet."
That ice sheet has seen its ice loss speed up and has lost an average of 278 gigatons of ice a year since 2000 as temperatures warm. The Antarctic has lost 92 gigatons a year over that time while other stashes of ice from Alaska to Patagonia are also melting and sending water to the oceans, redistributing the weight of the planet.
Adhikari and his colleague Erik Ivins published their findings in Science Advances on Friday, showing that melting ice explains about 66 percent of the change in the shift of the Earth's spin axis, particularly the rapid losses occurring in Greenland.
It's a huge, mind boggling process on the global scale, but imagine it like a top. Spinning a top with a bunch of pennies on it will cause wobble and drift in a certain pattern. If you rearrange the pennies, the wobble and drift will be slightly different.
That's essentially what climate change is doing, except instead of pennies, it's ice and instead of a top, it's the planet. Suffice to say, the stakes are a little higher.
Ice loss explains most but not all of the shift. The rest can mostly be chalked up to droughts and heavy rains in certain parts of the globe. Adhikari said this knowledge could be used to help scientists analyze past instances of polar motion shifts and rainfall patterns as well as answer questions about future hydrological cycle changes.
Ice is expected to continue melting and with it, polar motion is expected to continue changing as well.
"What I can tell you is we anticipate a big loss of mass from West Antarctic and Greenland ice sheets and that will mean that the general direction of the pole won't go back to Canada for sure," Adhikari said.
If it continues moving down the Greenwich Meridian or meanders another way remains to be seen, though.
"This depends highly on the region where ice melts, or if the effect of ice melt would be counterbalanced by another effect (for example sea level rise, increased water storage on continents, changes of climate zones)," Florian Seitz, the director of German Geodetic Research Institute, said in an email.
In the here and now, polar motion shifts matter for astronomical observations and perhaps even more importantly for the average person, GPS calculations.
More From Climate Central:
Climate Change to Cut Global Financial Assets by Trillions Clouds Play Lesser Role in Curbing Warming, Study Finds This article originally appeared on Climate Central, all rights reserved.
Before 2000, Earth's spin axis was drifting toward Canada (left globe). Climate change-driven ice loss in Greenland, Antarctica and elsewhere is pulling the direction of drift eastward.
You've heard a lot about how human-driven climate change will lead to hotter temperatures, cause sea levels to rise and make storms more intense. But it's projected to have plenty of other unpleasant and even disastrous effects as well. Here are 10 of them. Scientists believe that rising temperatures will lead to increased evaporation of the Great Lakes' water, and precipitation won't make up the difference. That means we're likely to see declines in water levels over the next century, and one study predicts they may drop as much as 8 feet.
Thanks to climate change, jumbo-sized ragweed plants will spew out more pollen for a longer, more miserable allergy season.
By altering the wild environment, climate change makes it easier for newly mutated microbes to jump between species, and it's likely that as a result, diseases will emerge and spread across the globe even more rapidly.
A recent Nature article reported that male Australian central bearded dragons have been growing female genitalia because of rising temperatures, a phenomenon that had not previously been observed in that species.
Rising sea levels are wiping out beaches all over the world already. Importing fresh sand and building them up again is only a temporary solution. To make matters worse, there's currently a sand shortage, due to demand from fracking, glass and cement making.
Bark beetles are eating old growth forests, because the winters aren't cold enough to kill them off. So more trees like this American Elm will die.
Warmer temperatures mean there will be more water vapor trapped in the atmosphere, leading to more lightning. A University of California-Berkeley study predicts that lightning strikes will increase by about 12 percent for every degree Celsius gained.
Wine grape harvests are being hurt. Regions that have historically supplied the world’s best wine will no longer be hospitable climates to grow wine grapes, according to research by the Environmental Defense Fund and others.
Coffee flavor depends upon really narrow conditions of temperature and moisture, and climate change is going to wreak havoc with that. Worse yet, as coffee growing regions become warmer, pests that couldn't survive in the past will ravage the crops. This is already being seen in Costa Rica, India and Ethiopia, which have experienced sharp declines in crop yields.
Scientists say that as ice sheets and glaciers melt, the weight that's removed from the Earth's crust changes the stresses upon volcanoes. That unloading effect can trigger eruptions.