Well, the short answer is 2037, plus or minus a few years.

That’s not a flippant answer, either. All forms of digital preservation really will stop around 2037, unless some kind of energy supply breakthrough happens.

How do we arrive at this date?

Let’s go thorough this step by step.

Technological collapse

The fundamental premise behind what follows is that digital preservation cannot survive the collapse of our technological civilisation. If you disagree with that premise, that’s fine, but you might as well stop reading now. It is always good to be clear about our premises before we begin. If you agree with the premise, then let’s carry on.

Paper records, if stored or hidden in a substantial box, can last centuries without any active preservation measures being undertaken. The civilisation which created those paper records might collapse, but the box could survive. A future civilisation can then discover the box, realise there is a message-bearing medium inside, and work out what it says. (It’s even better if the records are on stone. There’s a three thousand year gap between the Assyrian messages at Behistun and the 19th century European explorers who mapped and transcribed them, but that gap did not stop linguists from deciphering the cuneiform messages.)

Digital media have much shorter timespans. It is doubtful that a hard drive will be able to spin and deliver its data a few centuries after our society has collapsed. Technologically-dependent data storage therefore cannot survive massive societal collapse in the same way that non-dependent data can. 

We have arrived at the first possible answer to our question, which we will call answer A1:

A1: Digital preservation will come to an end when technological civilisation comes to an end.

Now let’s start to pin this down. When will technological civilisation come to an end?

Modern computing is wholly dependent upon hardware which in turn is wholly dependent upon fossil fuels for its creation and maintenance. The servers or CDs which preserve our data incorporate plastics which have been refined from crude oil supplied by OPEC. The dust-free clean rooms in which the chips are made are kept clean by energy derived from burning hydrocarbons. The finished computers are distributed globally by diesel-burning ships, which deliver them to ports from which the machines are then placed onto diesel-fuelled trucks for final distribution to warehouses and shops. The world’s ICT infrastructure is maintained by people who get to and from work in vehicles powered by petrol. Without crude oil none of this would happen.

The oil basis of modern ICT is an issue which gets raised from time to time. In December 2007 New Scientist reported that “computer servers are at least as great a threat to the climate as SUVs or the global aviation industry,” due to their carbon footprint. A 2004 United Nations study showed that the construction of an average 24-kilogram computer and 27-centimetre monitor requires at least 240 kilograms of fossil fuel, 22 kilograms of chemicals and 1,500 kilograms of water – or 1.8 tons in total, the equivalent of a sports utility vehicle.

Take away all this oil, plastic, petrol and diesel, and the world’s ICT structure becomes unsustainable. Motherboards become trickier to manufacture if you only have wood and brass. Gathering together the components and then distributing the finished machines becomes harder if you are dependent on sailing ships, horse-drawn carriages and barges for transport.

We can now refine our earlier answer. If we agree that digital preservation will come to an end when modern technological civilisation comes to an end, and if we then agree that modern technology is currently wholly dependent on oil and oil-derived plastics for its maintenance, then we arrive at the following statement:

A2: Digital preservation will end when the oil supply comes to an end.

But when will the oil supply come to an end? Never, in a sense, because at some point it will become too uneconomical for the world to drill out the last remaining drops. There will always be some oil left in the earth. Sadly that’s no help to us, because we will be back in the stone age by then.

A better question is, when will the oil supply start to run out?  – because that’s the point at which civilisation crashes; that’s the point at which any particular country can only increase its own oil and plastic by taking away oil and plastic from another country. And from that date, year on year, there will be less oil and plastic than the year before.

I’m no geologist, so let’s go to the experts on this one. The EIA (Energy Information Administration) is the energy data arm of the US government. In 2004 the EIA published a report on Long Term Oil Prospects, which looked at exactly this question. The report’s authors considered a number of likely scenarios for both (a) the total amount of oil in the ground and (b) the increase in demand for oil as time progresses. Then they mapped out all these scenarios.

This graph shows the three main scenarios, with the central one being the likeliest, as it is based on a world total oil production figure of about 3 trillion barrels of oil, which is the US Geological Survey’s assessment. The overall curve has a sharkfin shape. World oil supply rises upwards with a 2% annual growth rate until it peaks and then suddenly falls, when the world’s oil wells cannot meet demand. The peak comes in 2037.

So, for our purposes we can say that, as digital preservation will come to an end when the oil supply comes to an end, and as the oil supply will come to an end in 2037, we can then say that:

A3: Digital preservation will come to an end in 2037.

Certainly we will have bigger problems in 2037 than simply digital preservation. One problem which springs to my mind, as a UK citizen, is starvation. Much of our food in the UK is grown overseas (using fossil fuel-based fertiliser) and then shipped across. U-boat warfare almost starved Britain in the 1940s, yet back then we had more land under arable cultivation, a smaller population to feed, and a bigger proportion of our population was involved in agriculture. When the world’s shipping stops in 2037 digital preservation will be less of a priority than personal survival. As Peter Goodchild recently wrote, when the oil supply stops “our descendants will be smashing computers to get pieces of metal they can use as arrowheads.”

That doesn’t sound very optimistic.

No, but the oil might not run out in 2037. It might run out later (although the crash will be bigger).

Some people, such as the Peak Oil crowd who hang around at The Oil Drum, think the oil supply might be running out just about now, but I’m no energy expert so I’ll stick with the US government’s EIA on this one.

The longer we have, the better are our prospects at longer term digital archiving, because it gives the world more time to create and roll out a new ICT structure, one which doesn’t use oil-derived plastics, or depend on oil for distribution, power and maintenance. On the other hand, the shorter we have, the worse our prospects will be.