How many people are there living on Earth?

It’s a fascinating question with an official answer of 8.2 billion.

That’s a lot of people.

But incredibly, a new study from Aalto University in Finland suggests that our international governments are significantly underestimating the world’s population.

And the effects of this, they warn, could be catastrophic.

The real problem, the researchers note in their paper, which was recently published in the journal Nature Communications, is the fact that rural population numbers are extremely difficult to estimate. Sure, authorities rely on census and other data, but just how accurate are these when it comes to people living in relative wilderness?

Why is this a problem?

Well as Aalto University researcher Josias Láng-Ritter explains in a statement, our planet’s governments and international organizations use their understanding of populations to plan for crisis and disaster management. Everything from vaccinations and healthcare supplies to the routing of emergency infrastructure in determined by global population data:

“For the first time, our study provides evidence that a significant proportion of the rural population may be missing from global population datasets. We were surprised to find that the actual population living in rural areas is much higher than the global population data indicates — depending on the dataset, rural populations have been underestimated by between 53% to 84% over the period studied. The results are remarkable, as these datasets have been used in thousands of studies and extensively to support decision-making, yet their accuracy has not been systematically evaluated.”

This staggering new information shows just how difficult it is for our policymakers to plan for the worst.

In particular, the researchers found that population censuses are innately flawed, with urban areas significantly prioritized – and thus, more accurate – than rural settlements.

By interrogating population datasets derived from censuses from 1975 to 2010, the researchers found that the information from 2010 was missing just one third to three quarters of the world’s rural inhabitants, while older datasets were significantly more neglectful of rural people.

How do they know this? Well, they compared the official data to information obtained from dam projects, where local people have had to be resettled.

In the case of the dam projects, the population that was resettled was in most cases significantly higher than the census data would suggest, as Láng-Ritter explained:

“When dams are built, large areas are flooded and people need to be relocated. The relocated population is usually counted precisely because dam companies pay compensation to those affected. Unlike global population datasets, such local impact statements provide comprehensive, on-the-ground population counts that are not skewed by administrative boundaries. We then combined these with spatial information from satellite imagery.”

While the discrepancies were much higher in some places than other, the team found that this bias toward urban populations was the same across the world.

Given that over 40% of the world’s population live in rural settlements, the researchers point out that the real population of our planet is likely to be significantly higher than the estimate of 8.2 million. And the implications for this are profound, with Láng-Ritter expressing concerns in the statement:

“In many countries, there may not be sufficient data available on a national level, so they rely on global population maps to support their decision-making: Do we need an asphalted road or a hospital? How much medicine is required in a particular area? How many people could be affected by natural disasters such as earthquakes or floods?”

With natural disasters increasingly prevalent in a planet being ravaged by the growing realities of the climate crisis, accurate population estimates are more important than ever.

The time of prioritizing the urban dwellers has to be left firmly in the past.

If you thought that was interesting, you might like to read about 50 amazing finds on Google Earth.