NEW weather data shows the Arctic has just experienced its warmest winter on record, with scientists saying the lack of sea ice was “unprecedented” and a sign of severe climate change.

“It’s just crazy, crazy stuff,” said Mark Serreze, director of the US National Snow and Ice Data Centre in Boulder, Colorado, who has been studying the Arctic since 1982. “These heat waves, I’ve never seen anything like this.”

Last month’s record-breaking high temperatures at Cape Morris Jesup on Greenland’s north coast have been more like those in May, said Ruth Mottram, a climate scientist at the Danish Meteorological Institute.

Ice centre senior scientist Walt Meier said that “climate change is the overriding [cause].”

Scientists believe the warming Arctic is causing extreme weather further south.

Rutgers University’s Jennifer Francis warned that “the underlying disease that’s causing [extreme weather] is getting worse,” referring to greenhouse gases from the burning of coal, oil and gas.

Cases of extreme weather “are just the symptoms.”