We thought we were 8,000 million people throughout the planet. Until some researchers began to make numbers

In November 2022, the UN celebrated that we were already 8,000 million humans on earth. They are estimates, of course, but beyond the figure, the really interesting thing is that in 2023 We do not reach the replacement rate and that humanity will reach its peak at the end of the century to, irremediably, Start falling. But … to what extent can we trust those accounts? It is something that takes time on the table, and now a study It arrives to add more spicy when we affirmed that we have been making it counting.

So much that we have left several hundred million people along the way.

Can we trust the numbers? “Calculating the number of people on the planet is an inaccurate science.” That was the comment of demographer Jakub Bijak a BBC In the middle of last year, just when the Study of world population perspectives. Something scientific is something exact, but the researcher also commented that the only thing that can be sure when predicting population figures is of the lack of certainty.

That, eye, does not mean that demographers get the figures out of nowhere. “It is something difficult based on our experience, knowledge and each piece of information we have,” said Toshiko Kanera, an expert in demographic forecasts. The demographers drink from the data and trends of each country since 1950, but … what if it had not been well told?

We are missing millions. In a new study published in Natureresearchers from the University of Aalto in Finland show how the data sets that demographers manage to “deep and systematic” the population figures worldwide. The serious thing is that we would be talking about hundreds of millions more people living on earth.

The rural areas. Josias Láng-Rritter is one of the investigators in charge of the study and points to the accounts made in a specific segment: that of the rural population. “For the first time, our study provides evidence that a significant proportion of the rural population could be absent in the data sets of the global population,” he says.

As we say, we don’t talk about a few million, but thousands of millions. “Depending on the data set used, rural populations have been underestimated between 53% and 84% in the period studied. The results are notable, since these data sets have been used in thousands of studies and have widely supported decision making, but their precision has not been systematically evaluated,” says the researcher.

Biases. Attempts to review these data are not new, but previous investigations have focused on specific countries or urban areas. The researchers at the University of Aalto have wanted to take a more global photo when comparing the five most used population data sets worldwide. They have used maps that divide the planet into high resolution grids and have taken as a very concrete reference: the resettlement figures of more than 300 rural dams projects in 35 countries.

Why this dam bias? Because When a dam is builtthe population that lives in the area that will be flooded is relocated and precise resettlement data is usually had. When comparing this population data from 1975 to 2010, the researchers found that the 2010 maps were more precise, but still omitted between 32% and 77% of the rural population.

Between 2015 and 2020 the data sets were updated, but the demographers continue to consider that the underestimation of the rural population continues to exist and is a problem that persists in all regions of the world.

Consequences. And we are talking about a problem whose resolution is complex. According to researchers, no matter how much the data is reviewed, it is a structural problem. Governments do not have the resources to collect precise data in these rural regions, there is a huge discrepancy between the real population and the one reported in the population maps that are used to carry out demographic studies and that influences decision making.

And it is important. Current estimates place 43% of 8,200 million World inhabitants in rural areas -And 3,526 million people- and if we take into account that it is a percentage that has underestimated between 53% and 84%, we are not talking about little population, precisely. And it is essential to know exactly how many we are for a simple reason: the redistribution of resources.

No data. The lack of precise demographic records can affect political decision making. Ritter sets the example of social decisions. “In many countries, there may not be enough available data at the national level, so they depend on the global population maps to support their decisions: do we need an asphalted road or a hospital? How much medicine is needed in a specific area? How many people could be affected by natural disasters such as earthquakes or floods?”

Making quick accounts, in the best scenario – the 53% deviation in the rural population – we would talk about 1,869 million people who would not have counted. In the worst case, in the 84% not registered, we would talk about 2,962 million people. In Nature’s study, they put an example Paraguay, which in the 2012 census may have left out a quarter of the population.

Reviewing the methods. In the analysis of the team, there are countries that come out better than others. They put Finland as an example of reliable data, even in rural regions, because they began bringing digital records of the population 30 years ago. However, in countries in which this conscientious digital registry has taken longer to be implemented due to crisis of any kind, the differences between the real population and that they estimate can be significant.

“To provide rural communities with equitable access to services and other resources, we need to have a critical discussion about the past and future applications of these population maps,” says the researcher so that all countries can formulate more precise social policies Based on evidence and not so much on estimation.

Images | Owen Cannon

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