A Chinese research vessel's escape from pack ice after evacuating 52 people from a Russian ship trapped in Antarctica has shone a spotlight on the country's growing polar ambitions at both ends of the earth.
In the Arctic, China's strategic goals include the opening up of a "northeast passage" shipping route that Beijing hopes will shave days off the journey to Europe, its biggest export destination. And in the Antarctic, Beijing has mounted 30 expeditions and built three research bases - one at more than 4,000 metres altitude, on one of the frozen continent's highest ice caps.
Just as in the space race, experts say China is playing a long game in polar exploration, with the expected territorial and natural resource benefits decades, even half a century, away.
"At the moment, the only Antarctic resources that are really up to exploration are the marine living resources in the Southern Ocean," said Donald Rothwell, a professor of international law at Australian National University.
The Antarctic Treaty bans mining until at least 2048. But "some have observed China's development of its Antarctic interests allow it to be well-positioned if there is a change in the circumstances", Rothwell said.
The 1959 agreement designates the icy continent as a scientific preserve and bans military activity. China did not sign onto the pact until 1983, but has made stunning progress in ensuing three decades.
The Xue Long, or Snow Dragon, icebreaker was on a 155-day mission to construct a fourth Chinese station and survey a site for a planned fifth last week, when it came to the aid of the trapped Russian ship Akademik Shokalskiy. Its helicopter evacuated 52 people from the vessel, something the state-run Global Times said had reaffirmed "China's national progress".
"It is China's growing industrial capacity that empowers Xue Long to perform such a rescue operation," it said.
The ship later became stuck itself, but broke free to open water on Tuesday.
Video: China's Antarctic research ship 'Snow Dragon' breaks free from ice zone
The Xue Long's rescue mission will have given China "a great deal of kudos in the Antarctic community", Rothwell said. "All of that suggests to me that China is gaining a strong foothold and gaining great credibility in Antarctic affairs."
A new, more powerful icebreaker capable of clearing through floes 1.5 metres thick is due to be completed in 2015.
Beijing is devoting US$55 million annually to Antarctic research and exploration, according to Anne-Marie Brady, a professor at the University of Canterbury in New Zealand. That's up from US$20 million a decade ago.
That is still well short of the estimated US$300 million Washington spends on its Antarctic programme every year, and China's presence still lags other countries.
Argentina has 13 facilities on the continent, Russia 12 and the US six - and under the Antarctic Treaty there are limits on new territorial claims or enlarging existing ones. But China's moves at the ends of the earth have drawn concern from critics who say the agreement's territorial aspect is poorly enforced.
Some of the Chinese bases are within an expanse claimed by Australia, which claims 42 per cent of the continent and established the first permanent Antarctic base in 1954.
"We risk getting left behind," the Australian Strategic Policy Institute warned in a report in October. "China, a relative newcomer, is proposing its third station in the [Australian Antarctic Territory]. We've no presence at all in the neglected eastern sector. Effective occupation as a measure of sovereignty might be questioned."
Chinese foreign ministry spokeswoman Hua Chunying did not directly address the issue of a possible territorial claim when asked on Tuesday, but said China supported "the peaceful use of resources in the Antarctic for the benefit of sustainable development for humankind".
On the other side of the globe, China has made five expeditions to the Arctic and last May gained observer status in the Arctic Council, giving it a voice in deliberations over the region's future.