England and Wales have the “largest population ever recorded”, the Office for National Statistics trumpets in its first 2021 census bulletin, released today. You might get the impression from its placement at the top of the bulletin that this new record is interesting or surprising, or that it has some relevance for public policy. In reality, the fact that the population of England and Wales is 59.5 million tells us very little. What is more interesting is the speed of population growth (which has declined, from 7.8% in the 2000s to 6.3% in the 2010s). But even then, working out how much we should care is a tricky exercise. Population growth generates emotional responses in the UK. After the previous census results were released in 2013, MPs debated in parliament whether to use immigration controls to keep the UK population below 70 million. In one speech, the MP for South Dorset, Richard Grosvenor Plunkett-Ernle-Erle-Drax, banged the bench in front of him and announced: “Britain. Is. Full!” It’s a concern that resonates with many people – though few of us have Drax’s 5,600 hectares (14,000 acres) and deer park in which to contemplate the lack of space. At the other end of the spectrum are calls to address the “national crisis” of a declining birthrate and ageing population. The auditor general for Wales has flagged the falling birthrate as having “significant consequences” for public services. So is population growth good or bad? Or should we even care at all? From a purely economic point of view, the size of the total population doesn’t particularly matter. Our overall prosperity depends less on the absolute population than on what the people in that population are doing – for example, whether they are employed and using their skills productively. Population change is a bit more interesting. Declining populations can be a real problem economically and countries with declining populations tend to be pretty worried about it. If you’re losing people, you’re probably losing tax revenues that give you the ability to pay for the things that the remaining population needs. In some local areas you may no longer have the population to make amenities like schools and local shops viable. While most parts of England and Wales saw population growth over the past 10 years, 25 local authorities saw their populations decline, and this was particularly common in Wales and the north of England (although a handful of London boroughs are on that list too). Some politicians have worried that smaller populations can even mean declining influence. In his documentary, The Joy of Stats, the brilliant Prof Hans Rosling tells the story of the first modern census, undertaken by Sweden in 1749 in part as a means of assessing the potential size of the country’s military. King Gustav III had believed the country was a major power and had a population of about 20 million – enough to rival Britain and France at the time. When the data was finally revealed, the Swedes were horrified to discover the actual population was a mere 2 million. The country was small and vulnerable. But population growth can cause problems, especially if it happens too quickly. Public services may take time to catch up with rapid changes in populations. Schools and hospitals need to have adequate capacity, and infrastructure from sewers to roads needs to be able to cope. This is mostly a challenge of distributing funding to the right places, rather than population size per se – but adapting quickly to rapid changes in population by distributing the funds accordingly is not easy either. Growing populations need more houses to live in. Despite longstanding debates about whether there is “enough space” to find housing for everyone without building over green spaces, the reality is that more population per square mile does not necessarily mean less countryside. It depends how densely you build the cities. In fact, some economists have argued that concentrating the population in cities improves both economic prosperity and wellbeing. But the final point to consider here is whether most concerns being raised about population growth in the UK are really about population growth at all, or are actually about immigration and integration. Today’s ONS figures show that of the 3.5 million increase, 1.5 million was natural change, meaning migration was responsible for the remaining 2 million – or 57.5% of the change. Fewer concerns tend to be raised about the 42.5% increase in the population that is driven by natural change – people living longer and babies being born. Where concerns about these issues are raised, it is commonly related to births to migrant mothers. There are certainly legitimate and complex issues to be discussed about how migration and integration issues should be managed, but let’s be wary of the use of proxy issues such as population growth to camouflage these conversations.