The UK health media is currently focused on two natural threats to public health: one from swine flu, and the other from the heatwave currently affecting the country. Both flu epidemics and heatwaves frequently cause many deaths. For example, the August 2003 heatwave had a death toll in Europe of around 30,000, and a typical seasonal flu epidemic causes hundreds and thousands of deaths. Yet my impression is that, in the majority of the population, flu epidemics and heatwaves are not regarded as particularly great evils (flu pandemics, such as the current one, may be a different story).There's an obvious explanation for why they are regarded as less bad than killers such as road traffic accidents, wars and terrorism: these involve human action – and often human wrongdoing – in a way that flu epidemics and heatwaves do not. But flu epidemics and heatwaves also elicit a weaker reaction than many other natural events that typically kill far fewer people: for example, floods and earthquakes.
One reason why flu epidemics and heatwaves may seem less bad than other natural disasters is that they typically kill disproportionately people who are already ill. This means that the people they kill are, on average, losing fewer years of life, and lower quality years of life, than the victims of indiscriminate natural disasters like earthquakes. If the badness of death consists in the loss of good future life, then there's on obvious justification for regarding flu epidemics and heatwaves are less bad than other natural events.
A further reason to 'discount' the badness of heatwaves may be that they disproportionately kill the elderly. Again, this means that their victims are, on average, losing fewer years of life (and perhaps lower quality life) than the victims of indiscriminate killers, since older people typically have lower life expectancy than the average. There may also be further reasons to think that the deaths of elderly people are less bad than the deaths of younger ones. First, deaths of the elderly are less likely to interrupt incomplete life projects than other deaths. And second, deaths of the elderly may be less unfair than deaths involving younger persons – it might be thought that deaths involving the young are unfair because those persons have enjoyed less life than others despite being equally deserving of life.
It may be, then, that there are good reasons to believe that flu epidemics and heatwaves are typically less bad than earthquakes and floods. However, it's not clear to what extent beliefs about the badness are actually based on these reasons. It seems plausible that these beliefs are based in part on the fact that most of us – those who are not sick or old – have little to fear from heatwaves or (typical) flu epidemics (some flu epidemics do kill healthy non-elderly people). We thus lack self-interested reasons to care about these misfortunes, but this has no implications for how bad these things actually are, from a general or moral point of view.
It may also be that discount the badness of heatwaves and flu epidemics because we feel that there's little we can do about them. It's not clear to me whether this is a good reason to discount their badness or not. On the one hand, we might think that how bad something is should be conceptually distinguished from how preventable it is. Even if preventability is a determinant of badness, it's probably not the major determinant: after all, there are some outcomes that we would think of extremely bad even if they are entirely non-preventable (the death of our sun and resulting extinction of the human species might be one such outcome). On the other hand, there might be good reasons to believe that a bad outcome is worse just because it's preventable, even if this is not in fact the case. That is, there might be practical reasons to hold false beliefs about badness. After all, believing that an outcome is bad often motivates us to try to do something about it, and it's more important for us to be motivated to prevent a bad outcome when the outcome is indeed preventable, than when it is not. This raises the question of whether we should ever hold false beliefs because there are practical benefits from doing so.
Though there may be both epistemic and moral justifications for discounting the badness of heatwaves and flu epidemics relative to other comparable natural disasters, it's not at all clear to what extent widespread views about their badness are based on those justifications. An implication is that we should be careful not to simply take our common sense views about these natural misfortunes at face value. We should not, for example, assume that how much badness we would intuitively attribute to heatwaves provides an accurate measure of how bad heatwaves are, or how bad we should believe them, for ethical reasons, to be. How bad they actually are depends on the strength of the arguments for regarding the death of old or sick people as less bad than the deaths of others. And how bad we should believe them to be depends on these arguments as well as an assessment of the relative importance of ethical and epistemic reasons in forming beliefs.