Are there more detailed discussions of this risk that you can link to? I'm curious about synthetic biology's practitioners' justifications (or rationalizations) for having few safety measures, given how seemingly obvious the risk is to an outsider. In general, it seems like you're wasting the attention that you're drawing to this countdown by not pointing people to more information.
As a synthetic biologist, I justify the lack of regulation of my work by saying "I don't do that kind of synthetic biology." Saying "synthetic biology" could lead to a super-plague is like saying "computer science" could lead to an uFAI. Sure, but the majority of the work is harmless. The VAST majority. The only real safety measures I can think of that would work at this point would be censorship of disease research.
The FHI's mini advent calendar: counting down through the big five existential risks. The second one is a new, exciting risk: synthetic biology.
Synthetic biology
Current understanding: medium-low
Most worrying aspect: hackers experimenting with our basic biology
Synthetic biology covers many inter-related fields, all concerned with the construction and control of new biological systems. This area has already attracted the attention of bio-hackers, experimenting with DNA and other biological systems to perform novel tasks – and gaining kudos for exotic accomplishments. The biosphere is filled with many organisms accomplishing specific tasks; combining these and controlling them could allow the construction of extremely deadly bioweapons, targeted very narrowly (at all those possessing a certain gene, for instance). Virulent virus with long incubation periods could be constructed, or common human bacteria could be hacked to perform a variety of roles in the body. And humans are not the only potential targets: whole swaths of the ecosystem could be taken down, either to gain commercial or economic advantages, for terrorist purposes, or simply by accident.
Moreover, the medical miracles promised by synthetic biology are not easily separated from the danger: the targeted control needed to, for instance, kill cancer cells, could also be used to target brain cells or the immune system. This would not be so frightening if the field implemented safety measures commensurate with the risks; but synthetic biology has been extremely lax in its precautions and culturally resistant to regulations.