It might be the second most common element in the observable universe but until very recently, Earth, it was thought, was running out of helium. Aside from its obvious uses in balloons given out at children's parties by pizza restaurants, the noble gas actually has a number of vital medical and scientific applications—and in recent decades we've burned through most of our once-enormous reserves.

Helium is used mostly as a coolant, especially in MRI scanners, which use around one fifth of the world's reserves in liquid form to cool the machines' superconducting magnets. The semiconductor industry also uses it to grow crystals, while modern materials science also uses its high-yield cooling properties, as do certain advanced telescopes. Despite its uses, however, Earth was believed to be coming to an end of its reserves, having been allowed to squander what was once considered a fairly useless resource.

Researchers from Durham and Oxford universities, however, have surprised the scientific world by discovering a huge new reserve in Tanzania's Rift Valley in east Africa—using a new technique which could be used to find even more. It turns out that volcanic activity helps release the gas from the ancient rocks which usually hold it, allowing it to rise to shallower gas fields.

Diveena Danabalan, of Durham University's Department of Earth Sciences, said: "We show that volcanoes in the Rift play an important role in the formation of viable helium reserves. Volcanic activity likely provides the heat necessary to release the helium accumulated in ancient crustal rocks. However, if gas traps are located too close to a given volcano, they run the risk of helium being heavily diluted by volcanic gases such as carbon dioxide, just as we see in thermal springs from the region. We are now working to identify the 'goldilocks-zone' between the ancient crust and the modern volcanoes where the balance between helium release and volcanic dilution is 'just right'."

Further Reading Price shocks waiting as US abandons helium business

"This is a game changer for the future security of society's helium needs and similar finds in the future may not be far away," said Oxford professor Chris Ballentine.

Earth lost most of its helium billions of years ago, and much of the rest that remains is formed underground due to the decay of radioactive elements like uranium. That which makes it to the surface inevitably escapes from the atmosphere, as it is light enough to be overcome Earth's gravitational pull Oil and gas prospectors in the early 20th century realised that helium, which now only exists on Earth at about five parts per million, was unusually abundant in the USA's massive reserves of fossil fuels, and the American government soon built up huge underground storage facilities, notably in Amarillo, Texas, to collect the gas for use in barrage balloons. By the late 20th century, slightly before helium's usefulness as a coolant was fully realised, the expensive US National Helium Reserve was ordered by Congress to start selling the gas off—hence cheap balloons.

Before this new discovery, the US reserve—around 24 billion cubic feet—was slated to run out for good in 2018, putting the world at great risk of running out, or at least facing prohibitive costs for what was once an incredibly cheap resource. The price has risen 500 percent in 15 years, and while there were believed to be other supplies left in the world, including in Qatar and Algeria, the American sell-off was of such worry to academics it prompted the late Nobel laureate professor Robert Richardson to claim that party balloons should cost $100 (£75) a piece.

"Once helium is released into the atmosphere in the form of party balloons or boiling helium it is lost to the Earth forever, lost to the Earth forever," he said.

"In 1996, the US Congress decided to sell off the strategic reserve and the consequence was that the market was swelled with cheap helium because its price was not determined by the market. The motivation was to sell it all by 2015," he once told The Independent. "The basic problem is that helium is too cheap. The Earth is 4.7 billion years old and it has taken that long to accumulate our helium reserves, which we will dissipate in about 100 years. One generation does not have the right to determine availability for ever."

It remains to be seen whether this discovery will mark a new boom era for squeaky-voiced helium antics, or whether this new non-renewable reserve will be treated with more seriousness.