[joshuaissac]

The risk is of the rhetorical winter taking too long to roll around, and mirror life forms managing to hold on for long enough to gain the ability to feed on non-mirrored nutrients. In the worst-case scenario, with no predators, they could rapidly outcompete and replace the bottom end of the ecosystem, resulting in the collapse of everything above, which would be far worse than the slow-growing infectious diseases described in the article.