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Scientists from the University of Aalto in Finland, based on the results of a new study, say that official data on the world’s population exclude more than 50% of rural residents.
According to the latest UN data, 8.2 billion people live on Earth, and by the end of 21 century, the population could grow to 10.3 billion. Researchers note that these are very rough estimates, as it is impossible to count every single person on the planet. Some countries use sophisticated and fairly accurate population counting systems, but in others, the opposite is true, and the last census may have been conducted decades ago.
Finnish scientists emphasize, that about 850 million people on the planet do not have any documents that would prove their identity. The initial goal of the research was to determine how many people on Earth were forced to leave the place of residence due to the construction of dams.
Scientists have carefully analyzed 307 projects around the world to build dams in 35 countries, including China, Brazil, Australia and Poland. All of these projects were implemented between 1980 and 2010 and resulted in the displacement of thousands of local residents.
However, when trying to determine exactly how many people were displaced by the dams, the researchers found a large discrepancy in official data. Using displacement reports, the researchers estimated the population in rural areas before the dams were built. When they compared the figures to five major world population datasets, which break down individual regions into grids and estimate the number of people in each square, they found that, on average, the number of rural populations in these data was underestimated by 53%.
At the same time, in some cases, according to the researchers, the deviation in these estimates was 84%. That is, even the best data sets covered only about half of rural residents.
The study notes, that population data is often adapted mainly for cities, where the density of residents is much higher and information on the number of residents is easier to obtain. Rural areas are more difficult to map, and the available data is often incomplete.
In remote rural areas, the census may not cover all households. Communities affected by armed conflict or living below the poverty line may not be counted at all.
Most population databases also rely on satellite data to refine their estimates. This makes it relatively easy to map urban areas with large numbers of people and bright nighttime lighting. Remote villages can often be difficult to see due to the characteristics of terrain, a large number of trees, etc.
Countries and organizations use population data in infrastructure planning projects, resource allocation, and disaster response. Using inaccurate or incomplete data can have dire consequences. In particular, a disaster risk map that incorrectly accounts for the number of rural residents can lead to an inadequate and insufficient response. For the same reasons, rural areas may be deprived of adequate access to healthcare services.
Scientists emphasize that almost half of the world’s population still lives in rural areas. The availability of accurate data on the number of people living in rural areas is key to the UN’s global program to achieve sustainable development.
Finnish scientists do not challenge the official estimates of the world’s population, recognized by the UN. They merely draw attention to the limitations of the methods used in the global population count. Most of the data relates to China and other regions of Asia, which have traditionally underestimated their population. This may be less true for more socially developed countries such as Finland or Australia.
According to the researchers, if there is a genuine undercount of a large number of people, the authorities in the respective countries cannot help but notice it. The discrepancies can be reflected in data on energy use, food production, and even the use of mobile phones.
«The countries we looked at are very different, and the rural areas we studied have great differences between them. We are quite confident that this gives a representative sample for the whole globe», — says Josias Lang-Ritter, a researcher at Aalto University in Finland.
The Finnish researchers also plan to expand their analysis to include more recent data, as the current study only covers the period up to 2010.
The study was published in the journal Nature
Source: ZME Science