Rising sea levels have become very conspicuous over the past century such that scientists now believe it has reached the alarming level that is unmatched by any period in the past 6,000 years, The Guardian has learned.

According to scientists who studied and conducted a lengthy and laborious analysis on the trends of historical sea levels, the rising sea levels that we have right now is extremely unusual because of the 20cm rise in the sea levels worldwide.

The alarming increment is thought to have become conspicuous at the start of the 20th century.

The new study - which was led by the Australian National University and published in PNAS - identified rising temperatures as the primary cause of this serious phenomenon.

According to scientists, the inevitable increase in temperatures has led to the melting of polar ice and the thermal expansion of the sea.

Not only that, pumping large volumes of water for drinking water and agricultural use also contribute to the inevitable rising of sea levels.

As per the findings of the Australian National University scientists, the rising sea levels began when ice started melting 16,000 years ago. The slowdown in the changes of sea levels only became apparent until 6,000 years ago.

However, the rising of the sea levels got a boost about 150 years ago when humans began to burn fossil fuels, pumping large amounts of greenhouse gases into the atmosphere, according to USA Today.

"There's something going on today that wasn't going on before," lead researcher Kurt Lambeck said.

The tedious research was made possible by the two-decade-long collection of ancient sediment samples off Britain, Greenland, North America and the Seychelles.

Researchers only collected submerged sediments and some tree roots and certain mollusks, which were used in determining the previous sea level.

"It's like if you leave a big block of ice on the table, it doesn't melt instantaneously, there's always a delay in the system," Lambeck said.

"We know from the last interglacial period that when temperatures were several degrees warmer than today there was a lot more water in the oceans, with levels around 4 to 5m higher than today. The question is how fast that change occurs when you increase temperatures," he added.

In the end, the researchers maintained that there is no means to stop the rising of the sea levels.

"All the studies show that you can't just switch off this process. Sea levels will continue to rise for some centuries to come even if we keep carbon emissions at present day levels," Lambeck quipped. "What level that will get to, we are less sure about. But it's clear we can't just reverse the process overnight."

By the end of this century, the rising sea levels are expected to reach 1 to 3 feet based on this year's Fifth Assessment Report by the United Nations' Intergovernmental Panel on climate Change.

Nature World News reports that the US East Coast may experience daily tidal floods by 2045.