If we carry on using and throwing away metals at our current rate, important elements will become scarce remarkably quickly, says Harald Sverdrup (University of Lund). Sue Bowler asks how he knows, and what we can do to avert the technological and political fallout of peak metal.
Geoscientist 19.8 August 2009
Peak oil – the time when we are extracting oil at the highest rate, after which resources dwindle – has become a familiar term in the public mind, driving interest in conservation, efficiency and alternative energy. But hydrocarbons are not the only resources that will peak in this way. Many common metals will also reach their peak production rates on human timescales. Harald Sverdrup (Department of Chemical Engineering at the University of Lund, Sweden) is one author of a report* suggesting that some key elements that will become scarce far earlier than might be expected – with significant consequences for how societies think about and use our natural resources. One thing’s for sure – we can’t continue to imagine that any natural resources are limitless if we carry on using them the way we do now.
“People tend to think about peak oil, but peak metal is just a couple of decades behind,” says Sverdrup. The 20 most important metals will move into scarcity in the next hundred years. Some of these are metals where there is absolutely no shortage at all, at the moment. But we have to wake up and take serious thought about how we are going to manage this situation.”
Sverdrup, along with Deniz Koca (also at Lund) and Karl-Henrik Robért of consultants ‘the Natural Step “ in Stockholm, extrapolated from known and estimated resources, together with current and expected future extraction rates, to find out when we can expect metals to become scarce. There are a lot of uncertainties in this, Sverdrup admits, but they are confident that their estimates hold water. “We considered the resources we know to be left in the ground, both low grade and high grade, as well as the deposits we believe to be accessible” says Sverdrup. “And we looked at how long they will last at current and projected extraction rates. We combined three different mathematical methods to get our estimates: straight burn-off, the Hubbert curve and some dynamic modelling including the effects of changing the price, which have similar results to the Hubbert curve.”
Straight burn-off is the name given to extraction and use of all a resource, with no holding back for environmental aesthetics or when the price is low – the sort of situation, the report suggests, that applies only under a dictatorship or in a truly unregulated marketplace. The Hubbert curve is that established by M King Hubbert to model oil resources and works well – as does the dynamic modelling for a market where price affects demand.
Sverdrup, Koca and Robért combined these methods to find out when key metals will become scarce, and when production is likely to peak. They considered metals in three categories: those needed for infrastructure and technology, those essential for human subsistence, and those used for energy generation. The first and third of these can be considered: Running out of the first group could hold back technological development, as would, in a less direct way, the third. Running out of the second group would hold back development in a more fundamental way, but is unlikely to happen on the sort of timescale that matters.
So, what runs out first? “Helium, silver, gold, zinc, tin and indium will become scarce within 30 years”, says Sverdrup, if we carry on as at present. These metals offer a snapshot of the change of focus that Sverdrup and co-authors advocate if we are to manage resources effectively in the future. We think of silver and gold as precious metals, and their price means that they are to a large extent recycled, although not completely. But zinc, and tin?
Galvanised buckets are not yet considered precious, and are more often thrown to landfill than recycled. Indium is an example of elements that play key roles in electronics and the new technologies being developed for energy, to cope with peak oil and the atmospheric load of greenhouse gases. Platinum, lithium and gallium also have important functions in electronics, and they will reach their peak within 200 years – more quickly if they are used substantially more than they are today, perhaps driven by legislation addressing climate concerns.
“Precious metals are recycled because we know of old that we have to recycle them – and it pays for itself, like a bonus,” says Sverdrup. “You don’t throw gold, or platinum, or silver away. That same logic applies to other metals. Once nickel, say, gets to £80 or £100 per kilo, you don’t throw it away because that’s throwing away money. That these metals are too valuable to throw away has not sunk in yet.”
It’s not only metals that we can consider valuable now, but also elements that are abundant and widely used that will end up in short supply. “There’s supposed to be enough aluminium in the globe to last for ever” points out Sverdrup; “but the easy-to-extract ores will last less than another hundred years. There will still be plenty of aluminium, but it will exist in granite and extracting it is not an easy thing to do. You could do it, but it would take so much energy that you’d need an atomic plant for the job – and aluminium would no longer be a cheap metal. It would be like gold.” In other words, anyone wrapping their sandwiches in aluminium foil in 2150 would have to be seriously rich – and decidedly ostentatious.
Awareness of the imminent scarcity of metals will change behaviour, which in turn will alter these outcomes. “We need to realise that we have tough challenges ahead. We need to focus and be aware of the changes to come, and we have to be especially clever in closing the resource cycles by recycling – it’s good economic sense anyway.” And major boosts to recycling would significantly lengthen the ‘lifetimes’ of these resources; for example, getting recycling rates up to 90% means we use only 10% of the fresh resources we would have needed. But it is precisely for these strategic metals that recycling rates are pitifully low, typically around 30% for aluminium and ferrous metals. And elements used within electronics, in batteries and as alloys are more often not recycled at all, as you find when you try to get rid of an old computer.
The perceived reward of recycling will need to increase before it will be seen as worthwhile to separate out the many components of an old washing machine, for example, and this could take place via a shift in values. Manufacturing goods in such a way that these components can be recycled easily would increase the initial cost, but would give the final article more intrinsic value, suggest Sverdrup et al. But there’s also the associated costs of recycling, notably the energy use. Here, too, there is hope, but at the cost of significant change. Uranium used for conventional nuclear reactors is in the tranche of metals that will become scarce over the next century or so. “We will end up using the uranium very quickly, because the way that we use it is so poor” says Sverdrup.
“Only 0.7% of the uranium we get is burned for energy in conventional nuclear reactors. We can burn thorium in the same way and get the same very low rates of use as for uranium, and in 250 years it will all be gone, with an immense amount of waste. But if we were to use thorium in an alternative way in a new type of nuclear reactor, as is proposed by researchers in Canada, we would use 100% of it. There’s enough thorium for nuclear power plants worldwide for 25,000 years.” There’s a long way to go to develop this technology, but it does highlight the possibilities – and changes for the better – that can come about if resources are seen as finite, and worth making the most of, rather than limitless.
That is Sverdrup’s key message: “metals are not like confetti – they are much too valuable to throw away. But we have to think about these things.” Recycling rates far in excess of current dreams and vastly improved efficiency of use will bring many of these metals out of scarcity and give them effectively infinite lifetimes in use in modern life and technology. And, not incidentally, recycling metals better means we run less risk of being poisoned by our own metal waste – a nasty scenario Sverdrup and his co-authors summarise as “wading in our own dirt”.
It is easy to see some very gloomy prospects for the future, on the basis of today’s trends. As national oil and gas reserves fall, international supply and demand has already become a political weapon, for example in recent European winters. Strategic metal resources are also not distributed evenly round the globe, and will change international relationships, boosting the power of countries with the key deposits, whether currently rich or poor. The jockeying for position around regions such as the Arctic Ocean, where the hydrocarbon rights of the seafloor are in dispute, seems likely to get worse when mineral rights could mean controlling the supply of a strategic metal. Sverdrup is reasonably optimistic about the prospects for the future: “It’s not all doom and gloom – we can think of ways around these challenges, and there are good business possibilities ahead.”
However, it should be pointed out that this report is taking quite a long view. The authors limit their considerations to the current interglacial, reasoning that the next ice age will expose new accessible deposits and, anyway, result in a world that can support only one hundredth of the current world population – which would solve most resource problems. This interglacial is likely to be longer than usual, they think, given that the warming arising from greenhouse gases released by burning fossil fuels will prevent the inception of an ice age in a few thousand years, but there won’t be enough fossil fuels left to stop the next one.
* Towards a world of limits: Long term global supply perspectives for strategic metals and substances. H Sverdrup was speaking at the Golschmidt Conference 2009, held in Davos this June.