Ice in Greenland melts four times faster than 15 years ago, and big cities in America like New York can be flooded, scientists have warned.
Ice melts faster than experts expected, and they say it is likely to lead to faster sea level rise, due to warming of the Earth's increasing atmosphere.
The study flies before US President Donald Trump who has repeatedly rejected the scientific consensus on climate change.
He once claimed the phenomenon was a Chinese hoax intended to hurt American exports.
Researchers worry about global sea level rise that has focused on Greenland, where large glaciers drain ice chunks the size of icebergs into the Atlantic. The pieces float, eventually melting.
But a new study, published in the journal Proceedings of the National Academy of Sciences, found that the biggest continuous loss of ice from early 2003 to mid-2013 came from the southwestern region of the country, which was largely devoid of large glaciers.
The study's lead author, Professor Michael Bevis, from The Ohio State University in America, said: "Whatever this is, it cannot be explained by glaciers, because there are not many there.
"That must be the surface mass – ice melting inland from the coastline."
Liquefaction, which Professor Bevis and his colleagues believe is largely caused by global warming, means more rivers are flowing into the ocean during the summer.
The main finding of their study is that parts of Greenland, which were not previously considered a serious threat, are likely to become "major future contributors" to sea level rise.
Professor Bevis said: "We know we have one big problem with increasing rates of ice release by several large glacier outlets.
"But now we recognize the second serious problem: the more mass of ice will go as melt water, like the river flowing into the sea."
He said the findings could have "serious implications" for US coastal cities, including New York and Miami, as well as island nations that are very vulnerable to sea level rise.
And he warned there was no turning back.
"The only thing we can do is adapt and reduce global warming further –
"It's too late for no effect," he added.
"This will cause additional sea level rise. We see the ice sheet reaching a critical point."
Climate scientists and glaciologists have monitored the Greenland ice sheet as a whole since 2002 when NASA and Germany joined forces to launch Gravity Recovery and Climate Experiments, known as GRACE.
This involves twin satellites that measure the loss of ice throughout Greenland. Satellite data shows that between 2002 and 2016, Greenland lost around 280 gigatons of ice per year, equivalent to an annual sea level rise of 0.03 inches.
But the level of ice loss on the island is far from stable.
Professor Bevis's team uses data from GRACE and from GPS stations scattered around the coast of Greenland to identify changes in ice mass.
The pattern they found showed a "worrying" trend – in 2012, ice lost almost four times the rate that prevailed in 2003.
And the biggest surprise is that acceleration is focused in southwest Greenland, part of an island that was previously not known to lose ice quickly.
Scholar's findings are entirely strange with Trump's view.
Only on Sunday, the US leader made fun of the issue of climate change because the eastern United States was hit by temperatures as low as -22C.
He tweeted: "Be careful and try staying in your house. Most countries suffer tremendous amounts of snow and almost reach cold temperatures.
"How great is this system. It's not bad to have a little of that good old-fashioned Global Warming now! "
Trump is controlled by social media because of the lack of understanding of climate change which confuses him only with cold weather.