The current coronavirus (Covid-19) outbreak is likely the first pandemic to have a direct effect on many people around the world today, so it would hardly be a surprise if many people thought that such pandemics were a new phenomenon. The are not (for some history of pandemics, see this report from the BBC).

As I wrote in an Opinion Blog post on 16^th May 2017, human history is made up of a series of growth periods, interrupted by periods of zero or negative growth caused by disease. Population usually only starts to grow again when advances in medicine (e.g. the discovery of penicillin or the invention of vaccines) or public hygiene (e.g. the introduction of flushing toilets, drinkable water piped to houses, the invention of soap or the banning of public spitting) are made. Not all of these pauses in growth are caused by global pandemics (some have a smaller geographical footprint), but many are.

The Covid-19 pandemic is therefore part of a pattern, repeated very often in our past. History shows us clearly that pandemics, and other more localised (e.g. limited to a city) outbreaks occur when population density reaches a critical level. As each outbreak is solved, population grows to a new critical density level.

Some pandemics, such as the Black Plague, were solved not by innovations by humanity, but by the population reductions that the pandemic caused.

History also shows us that the human race has not learned the lessons it has tried to teach us. Continued population growth will inevitably cause more pandemics. Solving the Covid-19 pandemic will simply allow us to continue growing our population until the next one hits us. One day we will not defeat a pandemic; it will defeat us, either wiping out our species, or destroying our civilisation and pushing humanity back to the stone age.

It is never going to be possible to predict the nature of the next pandemic, so it will never be possible to pro-actively protect ourselves from the next threat (e.g. by developing a vaccine before the outbreak starts - just look at how unsuccessful we have been with seasonal 'flu shots, and our dismal failure to cure the common cold).

Of course, controlling population growth is an ethical and political minefield. Some people seem to believe that the "right to reproduce" is an inalienable human right, even though reproducing (especially excessive breading) takes away the rights to life, health and happiness of the other inhabitants of our planet. We urgently need to find a solution to this dilemma.