Adding a new clue to how the last ice age ended, researchers have revealed that New Zealand glaciers melted at the same time when European glaciers briefly expanded.

For the two decades since ice core records revealed that Europe was cooling at the same time Antarctica was warming over this thousand-year period, scientists have looked for an explanation.

And now a new study brings them a step closer by establishing that New Zealand was also warming, indicating that the deep freeze up north, called the Younger Dryas for the white flower that grows near glaciers, bypassed much of the southern hemisphere.

"Glaciers in New Zealand receded dramatically at this time, suggesting that much of the southern hemisphere was warming with Antarctica. Knowing that the Younger Dryas cooling in the northern hemisphere was not a global event brings us closer to understanding how Earth finally came out of the ice age," Nature quoted study lead author, Michael Kaplan, a geochemist at Columbia University's Lamont-Doherty Earth Observatory, as saying.

Ice core records show that warming of the southern hemisphere, starting 13,000 years ago, coincided with rising levels of the heat-trapping gas, carbon dioxide.

The study is the first to link this spike in CO2 to the impressive shrinking of glaciers in New Zealand.

The scientists estimate that glaciers lost more than half of their extent over a thousand years, and that their creep to higher elevations was a response to the local climate warming as much as 1 degree C.

To reconstruct New Zealand's past climate, the study's authors tracked one glacier's retreat on South Island's Irishman Basin.

The study has been published in Nature. (ANI)