Global warming is increasing the number of icebergs in the Southern Hemisphere

At least two clusters of more than 100 icebergs have split off their Antarctic ice shelf and are headed towards New Zealand, prompting authorities to issue navigation warnings for the southern coast of the island nation.

Scientists say the icebergs are remnants of the Ross Ice Shelf that broke off from Antarctica a decade ago. One of the largest chunks - nearly a mile long - was seen off the Macquarie Island coast 280 miles from New Zealand earlier this month. As the mass moves north and through warmer waters it continues to melt and break up into smaller pieces.