Nanotechnology as global catastrophic risk
The word ‘nanotechnology’ covers a broad range of scientific and technical disciplines. Fortunately, it will not be necessary to consider each separately in order to discuss the global catastrophic risks of nanotechnology, because most of them, which we will refer to collectively as nanoscale technologies, do not appear to pose significant global catastrophic risks. One discipline, however, which we will refer to as molecular manufacturing, may pose several risks of global scope and high probability. The ‘nano’ in nanotechnology refers to the numeric prefix, one-billionth, as applied to length: most structures produced by nanotechnology are conveniently measured in nanometres. Because numerous research groups, corporations, and governmental initiatives have adopted the word to describe a wide range of efforts, there is no single definition; nanotechnology fits loosely between miniaturization and chemistry. In modern usage, any method of making or studying sufficiently small structures can claim, with equal justice, to be considered nanotechnology. Although nanoscale structures and nanoscale technologies have a wide variety of interesting properties, most such technologies do not pose risks of a novel class or scope. Interest in nanotechnology comes from several sources. One is that objects smaller than a few hundred nanometres cannot be seen by conventional microscopy, because the wavelength of visible light is too large. This has made such structures difficult to study until recently. Another source of interest is that sufficiently small structures frequently exhibit different properties, such as colour or chemical reactivity, than their larger counterparts. A third source of interest, and the one that motivates molecular manufacturing, is that a nanometre is only a few atoms wide: it is conceptually (and often practically) possible to specify and build nanoscale structures at the atomic level. Most nanoscale technologies involve the use of large machines to make tiny and relatively simple substances and components. These products are usually developed to be integral components of larger products. As a result, the damage that can be done by most nanoscale technologies is thus limited by the means of production and by the other more familiar technologies with which it will be integrated; most nanoscale technologies do not, in and of themselves, appear to pose catastrophic risks, though the new features and augmented power of nano-enabled products could exacerbate a variety of other risks.