The sun over Greenland has risen two days early, baffling scientists and sparking fears that Arctic icecaps are melting faster than previously thought.
Experts say the sun should have risen over the Arctic nation's most westerly town, Ilulissat, yesterday, ending a month-and-a-half of winter darkness.
But for the first time in history light began creeping over the horizon at around 1pm on Tuesday - 48 hours ahead of the usual date of 13 January.
The mysterious sunrise has confused scientists, although it is believed the most likely explanation is that it is down to the lower height of melting icecaps allowing the sun's light to penetrate through earlier.
Thomas Posch, of the Institute for Astronomy of the University of Vienna, said that a local change of the horizon was 'by far the most obvious explanation'.
He said as the ice sinks, so to does the horizon, creating the illusion that the sun has risen early.
This theory, based on the gradual decline of Greenland's ice sheet, is backed by recent climate studies.
A report by the World Meteorology Organisation shows that temperatures in Greenland have risen around 3C above average over the last year.
It also reported that December was much warmer than usual with rainfall instead of snow recorded for the first time in Kuujjuaq since records began.
It has even been suggested that the sun's early appearance could have an astronomical explanation.
But Wolfgang Lenhardt, director of the department of geophysics at the Central Institute for Meteorology in Vienna, scotched this theory.
He said: 'The constellation of the stars has not changed. If that had happened, there would have been an outcry around the world.
'The data of the Earth's axis and Earth's rotation are monitored continuously and meticulously and we would know if that had happened.'