Oops. Another one of those interesting problems you never heard of that are really almost as important as the tears in Hillary's eyes in a New Hampshire diner . . .
Some of the great things that make human live much easier are dependent on rare non-renewable resources. Helium is one of these, a noble gas with remarkable qualities due to its inert state. It is used for example to cool metals needed to create superconductivity. This process is applied in the medical industry to make Multi-Resonating-Image( MRI) scans, a technique to produce images of body tissue, making accurate diagnosis of health problems without surgery possible. But Helium is also applied in nuclear magnetic resonance spectroscopty (NMR), for the arc welding of various metals amongst which are titanium, magnesium and aluminium, to reduce high-pressure risk in deep-sea breathing systems, to purge and pressurize liquid-hydrogen rocket propulsion systems, to find leaks in pipelines, as a coolant in certain nuclear reactor types, possibly for superfluid gyroscopes and last and for me definetly the least, to let balloons float.
Can Helium be substituted? The answer is no for applications which need cooling below a temperature of minus 210 degrees centigrade since that is the temperature at which the next best thing, liquid nitrogen, freezes. Helium on the other hand only liquifies at minus 260 degrees centigrade and stays in that state even down to absolute zero. Making it the most precious element for cooling at very low temperatures. For MRI scanning this means the available substitutes can only offer much higher temperatures at which the scanner can operate, implying less conductivity and therefore a less effective scanner.
The availability of Helium is thus quite important. So how long will this resource last?
Introduction
Helium is a gas that over time came into existence mainly from the radiogenic decay of uranium and thorium in the earth’s mantle. As it migrated to the surface it has remained trapped in underground fields combined with other gasses and in the earth’s atmosphere. The forming rate is too slow to be of any relevance in the timescale of a few human generations. Interestingly, very few studies are being done on the limitations of this resource. Only one research group in the entire world is currently studying the topic. The number of people who know a great deal about the future supply can be counted on one or maybe two hands. One of these is Phil Kornbluth, executive vice president of Matheson Tri-Gas Global Helium. For some background information on Helium I suggest listening to this interview with Kornbluth.
Types of Helium reserves
The sources of Helium on earth can be broadly divided into three categories; 1) Helium rich resources from natural gas fields with a helium concentration of 0.3% or higher; 2) Helium lean resources from natural gas fields with a concentration below 0.3% which mostly is uneconomical to extract; 3) Atmospheric Helium which will likely never be produced because it is too energy intensive to do so. For the two sources of Helium from natural gas, there is little known about the energy costs of production since Helium has so far been produced as a by-product of natural gas production. In this case only produced when the lifetime of the natural gas field and the gas resources warrant the construction of infrastructure to produce Helium for 20 years or longer.
EDIT
http://europe.theoildrum.com/node/3484