It sounds unlikely but it's true -the magnetic north pole is moving faster than at any time in human history, threatening everything from the safety of modern transport systems to navigation routes of migrating animals.

Scientists say magnetic north, which for 200 years has been in the icy wilderness of Canada, is moving west towards Russia at about 65km a year.

The speed of its movement has increased by a third in the past decade, prompting speculation that the field could be about to "flip", causing compasses to invert and point south rather than north, something that happens between three and seven times every million years.

The phenomenon is already causing problems in aviation.

Tampa International airport in Florida has spent a month renaming its three runways, which like those at most US airports are identified using numbers that correspond to the direction, in degrees, that they face on a compass.

The speed of magnetic north's movement away from Canada's Ellesmere Island is throwing out compasses by roughly one degree every five years.

Geologists believe the magnetic north pole - which is different from the true North Pole, the axis on which the Earth spins - moves because of changes in the planet's molten core, which contains liquid iron.

The speed of that movement increased significantly from about 1989, possibly because of a "plume" of magnetism deep below ground.

GPS systems, which rely on satellites, have replaced compasses as the guidance system for professional navigators.

But compasses are still valuable, and are still widely used. In some places which cannot be reached by satellite signals, they remain the only option.

Birds that fly south for the winter, and migratory sea creatures, could face confusion. Long-living animals, such as whales and turtles, may have to recalibrate their navigational instincts.