Will ours be a "century of viral pandemics", "the century of drought" - or both, and more? These headlines (from the Independent) show how the media are always on the lookout for the next big scare. And both these threats are sure to feature on the "register of risks" that the government plans to publish this year as part of the national security strategy, announced last month by Gordon Brown.

The trouble is that we live in pretty safe times. Instead of vivid dangers (wild beasts, say), we face distant threats. The further they are postponed, the more apt we are to discount them. Yet, at the same time, the threats are many and varied. This leaves us unsure how to respond. Economists have shown how bad we are at making decisions that involve weighing risks even with known values. Most of the risks that would feature in a register are the nebulous but potentially catastrophic ones beloved by the press.

Bird flu is a good example. Some scientists genuinely fear H5N1's potential to mutate into a human-transmissible form; others say that because it hasn't done so yet, it probably won't now. How do you weigh that risk? A pandemic of another kind is possible, but that is not to say, as the media love to do, that one is "overdue".

The strategy raises other problems. It's a fair bet that the register won't include many of the things statistically likely to hurt you - heart disease, road accidents, chronic illness - because they lack the requisite drama. Other risks, notably climate change, are not framed nationally, so the role of any national strategy is limited. The register apparently won't offer guidance on what people should do about the risks it advertises. Yet unless somebody does, it might be just another tease. It would replicate for other risks the government position on terrorism, which asks us to be alert without telling us what to be alert for, thereby merely encouraging undirected fears and increasing public panic.

If we cannot respond usefully, we can at least talk. However vague, these risks, once imagined, can be communicated and amplified. According to Mary Douglas and Aaron Wildavsky's Risk and Culture, "people select their awareness of certain dangers to conform with a specific way of life". And at the moment they are selecting from the all-you-can-eat buffet served up by the media. Our water-cooler gossip - about where's safe to go on holiday, whether to give our children the MMR jab, the safety of genetically modified foods and the rest - leads either to a consensus about the risk that serves to strengthen the social fabric, or disagreement that weakens it.

Talking about the risks we face may not only help us set priorities as to what we feel are the greatest dangers, it might also prove to be the elusive national glue Brown is so keen to find, which will cement an idea of British identity. It will be a shame, however, if it turns out that all we have in common is our fears.

"Panicology" by Hugh Aldersley-Williams and Simon Briscoe is published by Viking (£18.99)