British polar explorer Ben Saunders was even forced to a abandon an attempt to ski solo from northern Russia across the North Pole to Canada on Monday, saying he had been amazed at how much of the ice had disappeared.
"It's obvious to me that things are changing a lot and changing very quickly," a sunburned Saunders said less than two days after being rescued from the thinning ice sheet close to the North Pole.
The adventurer has been in the region three times in the last three years for extended periods of time.
No Arctic icecap?
An international study last year said global warming would melt most of the Arctic icecap in summertime by the end of the century.
Many scientists blame the rising temperatures on human emissions of greenhouse gases while others point to what they say are longer-term natural warming and cooling cycles.
"The temperatures were incredibly warm ... I had days when I could ski with no gloves and no hat at all, just in bare hands, because I was too hot," said Saunders.
"It's obvious to me that things are changing a lot and changing very quickly"
Last month, the average temperature was just -6C, compared to -17 just three years ago.
Saunders had planned to set off from Russia's northernmost Arctic islands in March but instead of ice, he discovered a 70km open stretch of water. He had to be flown to the closest pack ice.
Bad news for bears
The explorer also noticed the almost complete absence of polar bears on the Russian side.
"That surprised me a lot ... that's historically been a very concentrated area for bears," he said.
"Whereas in 2001 we were attacked by a bear on day two [of the trek] and saw bear tracks nearly every day for the first three weeks, this year I saw four sets of tracks during the entire expedition."
Polar bears hunt out on the ice during summer months and are forced to retreat inland when the ice is too thin.