In my initial post in this series, I asked, "What if nanotechnology could deliver on its original promise, not only new, useful, nanoscale products, but a new, transformative production technology able to displace industrial production technologies and bring radical improvements in production cost, scope, and resource efficiency?"

The potential implications are immense, not just for computer chips and other nanotechnologies, but for issues on the scale of global development and climate change. My first post outlined the nature of this technology, atomically precise manufacturing (APM), comparing it with today's 3D printing and digital nanoelectronics.

My second post placed APM-level technologies in the context of today's million-atom atomically precise fabrication technologies and outlined the direction of research, an open path, but by no means short, that leads to larger atomically precise structures, a growing range of product materials and a wider range of functional devices, culminating in the factory-in-a-box technologies of APM.

Together, these provided an introduction to the modern view of APM-level technologies. Here, I'd like to say a few words about the implications of APM-level technologies for human life and global society.

Solving major global problems

A surprising range of global problems can be seen as problems of manufacturing, not solvable by manufacturing alone, of course, but transformed and made more tractable by better ways to make things. Global material economic development is, fundamentally, a problem of making things that serve human needs, whether these are power systems, medical supplies, or consumer goods. Similarly, resource depletion is a problem involving the materials needed to make things and the costs (both economic and environmental) of producing and recycling those materials; better ways to make things with frugal use of common materials could bypass mines and restructure international trade.

And a switchover to renewable solar photovoltaic energy? This is a matter of producing enough photovoltaic panels, packaged for low-cost deployment. Getting the resulting energy to people? This is a matter of producing electric power transmission infrastructure. Producing liquid fuels from renewable energy? This is a matter of processing molecules (CO 2 + H 2 O + energy —> hydrocarbon fuels + oxygen), and atomically precise manufacturing can provide the required energy and high-throughput catalytic mechanisms.

Even reversing the CO 2 problem is, in the end, a problem of manufacturing, a one that could be solved with enough energy and equipment for CO 2 capture and compression. Both expanding energy supplies and capturing CO 2 are primarily problems of producing the requisite devices, but on a daunting scale. The project would require some 30 terawatt-years of non-carbon-based energy, enormous when compared to the three terawatts of electric power produced by the world today. To provide the necessary energy in the span of a decade would require photovoltaic arrays covering about 1% of the area of the Sahara desert – 100bn square metres would be enough. This would be too costly with today's means of manufacture, but practical at some time in the future with APM-level technologies.

These examples suggest that atomically precise manufacturing could not solve, but could provide the means to solve problems that are beyond the reach of industrial technologies. And the task of developing APM-level technologies is itself a problem of manufacturing, a task that will require an incremental climb up a ladder of production technologies that extends today's surprising progress in atomically precise fabrication.

Raising new concerns

Every major advance in making things can have both beneficial and harmful applications, and even beneficial applications have unintended (and often unpredictable) consequences. It seems that APM-level technologies can lead to problems of three main kinds:

• The potential manufacture of desirable products on a scale that, unless moderated or managed, would cause deep economic disruption by collapsing demand for many sorts of natural resources, labour, and conventional products.

• The potential manufacture of products that, unless forestalled by law or regulation, could cause harm (for example, drugs, guns, and devices prone to exploding or worse).

• Of special concern, the potential manufacture of weapons that, unless forestalled by co-operative arms control, could lead to a risky and unpredictable arms race: imagine rapidly deployable arsenals that include millions of cruise missiles, each delivering up to millions of drones no larger than wasps, able to disperse, communicate, wait, watch, and then act when triggered. Or simply consider the prospect of efficient uranium isotope separation equipment made as easily as a plastic gadget from a 3D printer.

These concerns all involve APM products, because APM production technologies in themselves can by their very nature (and with a bit of sensible regulation) be cleaner and safer than the technologies they replace. APM is a particular kind of factory-in-a-box technology – no dispersed particles, wandering bots, toxic materials, or anything gooey, but instead a machine that resembles a printer. APM is a specific kind of technology but its products, by contrast, can be extraordinarily diverse. Like the nanotechnology used to build information systems, APM's products and applications can be as different from one another as online games, drone guidance systems, smartphones, and Wikipedia.

Asking the right questions

If there's anything to the concept of high-throughput atomically precise manufacturing, then it's important to understand what it may mean for our future. The way forward in understanding that these prospects starts with asking the right questions.

The first question must be‚ "What is it?" in the most basic, physical sense, because without this understanding, any conversation will immediately run off the rails. I outlined the basic nature of the technology in my first post, drawing parallels with digital systems, 3D printing and conventional manufacturing. Digging deeper into this question involves exploring the molecular physics and mechanical engineering of nanoscale systems of particular kinds, systems that can be understood in terms of today's science, yet are beyond the reach of today's technology. As I mentioned, there is some institutional weight (the US National Academy of Sciences APM-feasibility study, etc) behind the idea that the science and engineering of APM systems makes sense.

With this picture in place, the next question is‚ "Can it be built?" The answers to this depend on the timeframe: not today, because we don't yet have the necessary toolkit. Yes, in the future, because the necessary toolkit can be developed through further progress in atomically precise fabrication. Note that this progress centres on the molecular sciences and often isn't labelled as "nanotechnology".

A further layer of questions asks‚ "What can APM-based production enable?" The answers here are uncomfortably broad: asking what APM systems can do with materials is much like asking what computers can do with information.

The most important questions look one step further, asking‚ "What are the potential consequences?" These questions involve the physics and engineering of APM-enabled technologies, of course, but they centre on anticipated and unanticipated human actions. Among these, the key questions will involve potential societal agreements and regulatory regimes that seek ways to apply APM-enabled technologies to solve human problems while minimising potential misapplications and disruptive results.

These questions and answers, asked and discussed in a host of venues, will reframe the potential future of 21st century material civilisation. Timelines, applications and outcomes will depend on how well and how widely APM-level technologies are understood and how we choose to manage them.

I find that asking these questions opens the door to a banquet of indigestible truths, yet if the prospects are real, it's time to start nibbling. And this means beginning to broaden our conversation about the future to take account of new possibilities.

Eric Drexler, often called "the father of nanotechnology", is at the Oxford Martin Programme on the Impacts of Future Technology, University of Oxford. His most recent book is Radical Abundance: How a Revolution in Nanotechnology Will Change Civilization

The Oxford Martin School of Oxford University and the Research Center for Sustainable Development of the China Academy of Social Sciences recently released a report on atomically precise manufacturing, Nano-solutions for the 21st century. The report discusses the status and prospects for atomically precise manufacturing (APM) together with some of its implications for economic and international affairs.