A list of "endangered elements"  has been published in a new report, including the rare earth elements (REEs) in particular neodymium, production of which, it is reckoned , will have to increase five-times to build enough magnets for the number of wind-turbines deemed necessary for a fully renewable future. Nonetheless, my rough calculations indicate that this would still take 50 - 100 years to implement, depending on exactly what proportion of the renewable electricity budget would be met from wind-power, and if the manufacturing capacity and other resources of materials and energy needed for this Herculean task will prevail.
Neodymium is a rare earth metal used extensively to produce permanent magnets found in everything from computer hard disks and cell phones to wind turbines and cars. Neodymium magnets are the strongest permanent magnets known, and a neodymium magnet of a few grams can lift a thousand times its own weight. The magnets that drive a Toyota Prius hybrid’s electric motor use around 1 kilogram of neodymium, while 10 - 15 kg of lanthanum is used in its battery . Interestingly, neodymium magnets were invented in the 1980s to overcome the global cobalt supply shock that occurred as the result of internal warfare in Zaire (now Congo). Around one tonne of REE based permanent magnets is needed to provide each MW of wind-turbine power.Of the other REEs, demands for dysprosium and terbium, which are harder elements to extract than their lighter relatives, are such that supply will be outpaced within a decade.The latter have been described as "miracle" ingredients for green energy production since small quantities of dysprosium can result in magnets with only one tenth the weight of conventional permanent magnets of similar strength, while terbium can be used to furnish lights that use as little as 20% of the power consumed by normal illumination. By alloying neodymium with dysprosium and terbium, magnets are created that more readily maintain their magnetism at the high temperatures of hybrid car engines .
However, far more dysprosium relative to neodymium is required than occurs naturally in the REE ores, meaning that another source of dysprosium must be found if hybrid cars are to be manufactured at a seriously advancing rate. 97% of REEs come from China, and it appears that China will run out of dysprosium and terbium within 15 years, or sooner if demand continues to soar. The joker in the pack, is that Chinese hegemony for its own future energy projects may mean that the current amount of REEs being released onto the world markets will be severely curbed.
Peak oil may already be with us, and peak coal in 10-15 years, while peak lithium remains a subject of speculation. Peak neodymium is the latest threat to green-energy, while doubt emerges over the security of many other element groups including the rare earths, the platinum group metals, and elements such as antimony, beryllium, gallium, germanium, graphite, indium, magnesium, niobium, tantalum and tungsten. Helium (used to cool superconducting magnets in hospital MRI scanners) and phosphorus (in agricultural fertilizers) are also under threat.
If even "renewables" cannot save us from waning fossil fuel depletion, the only solution is to begin seriously the deceleration of consumption to a lower-energy society based around local communities immediately, with vastly reduced inputs of energy and all kinds of "mined" resources. Recycling must be key to this most difficult transitional step, in hand with a new concept of a "circular economy", that aims to model nature where nothing is wasted.
Related Reading. "Critical Thinking," By Emma Davies. http://www.rsc.org/chemistryworld/Issues/2011/January/CriticalThinking.asp
 "Going "All The Way" With Renewable Energy?" By Mason Inman. http://news.nationalgeographic.com/news/energy/2011/01/110117-100-percent-renewable-energy/