By Thomas Buch-Andersen
BBC News, Copenhagen
"Dragons be here!" That is how the unknown region of the North Pole was marked on ancient Danish maps.
Greenland icebergs: Melting ice may make exploration easier
Much still remains to be mapped and Denmark is engaged in that work now, with a new polar expedition.
Cutting through ice as thick as five metres (16.5ft), 45 scientists are on a mission to explore what is really beneath the frozen sea.
The aim is to gather data showing whether there is a basis for a possible future Danish claim to parts of the Arctic. If evidence is found to prove that the North Pole is geologically linked to Greenland - part of Denmark for more than 600 years - then the kingdom could stake a claim to the pole itself.
According to the latest estimates from the US Geological Survey, the North Pole region holds about a quarter of the world's oil reserves. As global warming continues to melt polar ice, access to the oil reserves should get easier.
The prospect of "black gold" in Greenland has led a growing number of Greenlanders to call for independence from Denmark. A Danish government commission is set to publish recommendations on the future status of Greenland next month.
And the North Pole is not the only source of potential riches in the region. According to the US Geological Survey, the north of Greenland could hold the richest untapped oil and gas reserves.
The Danish Prime Minister, Anders Fogh Rasmussen, has said he is following the polar expedition with great interest. But he added that at this stage Denmark is not preparing to claim the North Pole.
Russian researchers planted a Russian flag on the North Pole seabed on 2 August.
Russia has staked an early claim - but the UN wants more data
"It's not a good thing that various nations are making claims to the North Pole," Mr Rasmussen said. "Now, I am not an expert, but I tend to think that the North Pole is shared property for the whole world."
However, Science Minister Helge Sander has said Denmark has joined the race because Danish scientists believe the North Pole does belong to their country. That has led the opposition to call for the government to make its intentions clear.
"While the prime minister says the North Pole is shared property, the science minister has hinted that the North Pole - or parts thereof - is Danish property. We need the government to make a clear stand," said Rasmus Prehn, Social Democratic shadow spokesman on science.
Russia claims the North Pole is part of Russia. Mr Sander called the Russian expedition a "provocation".
Canada has also shown a keen interest in the Arctic. The Canadian Prime Minister, Stephen Harper, went on a three-day trip to the region earlier this month and said Canada would build two military facilities there.
Race for data
"It's the first time we see this type of diplomatic wrangling and border twists between Western nations as a result of climate change," Bart Mongoven, a scientist with the American think-tank Stratfor, told the Danish newspaper Politiken.
"We could see some serious conflicts of interest, and they won't all have peaceful solutions," he said.
Canada, Denmark and Russia are among many countries that have ratified the UN's Convention on the Law of the Sea, which allows a state sole exploitation rights over all natural resources within a 200-nautical mile (370km) zone extending from its coastline.
Beyond that, a state can claim the right to exploit a further 150 nautical miles of seabed if it can prove that its continental shelf extends that far.
Unlike the states now racing to the North Pole, Norway has already gathered and submitted evidence to make its claims. But Norwegian scientists appear to think that, while part of the region is Norwegian territory, the pole itself is not Norwegian.
There is still a long way to go before Denmark - or any other nation - can stake an official claim to the North Pole.
"We are not guaranteed any success. No one has sailed this area before. The real challenge is the ice," said Christian Marcussen, a leading scientist responsible for the expedition.
He warns against raising expectations too high because of the harsh weather and water conditions.
"It's unrealistic to think that we can drill for potential oil in our lifetime. The problem is the drifting ice which is very difficult to handle. However, there might be certain bacteria or other unique resources underground that could be valuable in future," said Mr Marcussen.
Flemming Christiansen, another scientist at Denmark's GEUS (Geological Survey of Denmark and Greenland), says Denmark is not only interested in the North Pole's potential oil, gas and bacteria. The region is already an attractive sea route.
A successful claim to the North Pole would also allow a state the power to regulate traffic and set environmental standards.
By 2014 the UN will be looking at the scientific evidence gathered by the various national expeditions.
If a scientific battle breaks out, it is ultimately the UN's International Court of Justice in The Hague that may decide to which country the North Pole belongs - if any.
RUSSIA'S ARCTIC CLAIM
1) North Pole: Russia leaves its flag on the seabed, 4,000m (13,100ft) beneath the surface, as part of its claims for oil and gas reserves
2) Lomonosov Ridge: Russia argues that this underwater feature is an extension of its continental territory and is looking for evidence
3) 200-nautical mile (370km) line: Shows how far countries' agreed economic area extends beyond their coastline. Often set from outlying islands
4) Russian-claimed territory: The bid to claim a vast area is being closely watched by other countries. Some could follow suit