China's colossal red icebreaker, the Xuelong or Snow Dragon, embarked on a 155-day expedition to Antarctica on Thursday. The voyage marks China's 30th trip to the continent, and many of the 256 crew are scientists hunting meteorites. Also onboard are construction materials to establish the country's fourth Antarctic research station, Taishan, which is to be located in Australian-claimed territory, a vast area of East Antarctica that houses an unknown wealth of coal, iron ores, manganese and hydrocarbon.

In 1960, one year before the Antarctic Treaty came into force, a geologist declared before the US science academy that he "would not give a nickel for all the resources of Antarctica". Today, in a world of dwindling fossil fuels and soaring energy needs, countries are spending lavishly to explore the potential of the world's last unexploited continent.

China, which is resource-scarce, is unambiguous about its polar aims. At a Politburo committee conference in July, president Xi Jinping emphasised the necessity of polar exploration to "take advantage of ocean and polar resources", according to a government website.

In the north, China has been granted observer status by the Arctic Council, allowing it more influence. In the south, the country is rapidly building research stations – a method of assertion on a continent where sovereignty is disputed. In 2003, China's yearly Antarctic spending was £12m; by 2013 it was £35m, accounting for 80% of the total polar budget.

Photograph: Robb Kendrick/Aurora/Getty Images

Article seven of Antarctica's Protocol on Environmental Protection stipulates that activity relating to mineral resources, other than scientific research, is prohibited. But this ruling, up for review in 2048, allows geological surveillance. "It is necessary for us to fully understand the resources on the continent," says Guo Peiqing, a professor of law and politics at the Ocean University of China. "China's exploration of the continent is like playing chess. It's important to have a position in the global game. We don't know when play will happen, but it's necessary to have a foothold."

As budgets of long-established states shrivel, those of newer players including India, South Korea and China expand. The focus on resources by some countries has been of concern to those who value the conservation ethic of the treaty, which protects the continent as a science preserve. "One of the things that's of concern in Antarctic governance is a lack of genuine checking up of what countries are doing," says Anne-Marie Brady, author of an upcoming book on China's polar strategy.

Brady adds that the energy needs of many nations in 2048 will differ from today. If predictions about Antarctica's 200 billion barrel oil capacity prove correct, the continent's reserves would be third largest in the world, according to the Lowy Institute. Fresh water is also abundant. As persistent high temperatures melt ice from the 1.5m sq km of coastal shelf, scavenging could become a reality in a water-hungry world.

With Antarctica, there is much at stake. As a carbon sink, the continent plays an essential role in global weather. The Antarctic Bottom Water – the coldest and most oxygen-rich deep-water body on earth – ventilates the world's seas, and excessive fishing or offshore drilling will decrease its oxygen content, reducing efficacy. Environmental groups have long been worried about the overexploitation of krill, a crustacean vital to its ecosystem, as well as the longevity of the toothfish.

Decision-making in Antarctica is consensual. As countries with conflicting agendas strive to further national interest, the ability to protect Antarctica's ecology weakens. Already the international body established to protect marine life is struggling to ratify new measures. At a meeting last week of the Commission for the Conservation of Antarctic Marine Living Resources, two proposals for new protected areas were stalled when China, Russia and Ukraine withdrew support over fears about fishing curbs.

"It's inevitable that people will want to go to Antarctica because they've taken too much fish from everyplace else," says James Barnes, executive director of the Antarctic and Southern Ocean Coalition. "But it's not inevitable that they [will] get to do so."

• Additional research by Xia Keyu