Scientists propose halving world population
Reducing the global population to around four billion by 2200 could ease pressure on natural resources, slow climate change and create conditions for wildlife recovery. This is the conclusion reached by the authors of a study published in the journal Sustainable Development, Qazinform News Agency reports.
The study examined global data from 1970 to 2020. The authors compared population growth with eight environmental indicators: carbon dioxide emissions, energy and freshwater consumption, mineral extraction, plastics production, pesticide use, ecological footprint and changes in wildlife populations.
In just half a century, humanity has become several times “heavier” on the planet. Between 1970 and 2020, the world’s population more than doubled, while global energy consumption nearly tripled, mineral extraction increased more than fourfold and plastics production rose approximately 13-fold.
Today, around seven tons of minerals are extracted annually for every person on the planet. That is equivalent to the weight of several cars. Almost 60 kilograms of plastic are also produced per person, compared with less than 10 kilograms in 1970. Plastics provide perhaps the clearest example that the problem lies not only in the number of people, but also in changing patterns of consumption.
The situation with carbon dioxide emissions is different. Over 50 years, total emissions more than doubled, although the annual figure per person rose only slightly, from 3.87 to 4.09 tons. According to the authors’ calculations, population growth was the main factor behind the overall increase.
The consequences are evident beyond consumption statistics. Every new city, road or agricultural field requires land that may once have been forest, steppe or wildlife habitat. During the period examined, the Living Planet Index, which tracks populations of more than 5,000 vertebrate species, fell from 1 to 0.27.
What happens next will depend on the world’s demographic trajectory. The researchers considered two dramatically different visions of the future.
Under the most favorable scenario, the global population would decline to 6.9 billion by 2100 and approach 4.1 billion by 2200. According to the model, annual CO₂ emissions could fall from 32 billion to 16 billion tons, plastics production could decline from 460 million to 54 million tons, and natural ecosystems would have an opportunity to recover gradually.
The opposite scenario projects the global population reaching 11.4 billion by the end of this century and 21.2 billion by 2200. If the relationships observed since 1970 continue, annual plastics production could exceed 13 billion tons, energy consumption could triple compared with current levels, and wildlife populations could approach a critical threshold.
The authors, however, do not present these figures as precise predictions. The model extends historical trends and cannot fully account for future technological breakthroughs, policy decisions or regional differences. Instead, it is intended to demonstrate how dramatically the consequences of different demographic choices could vary.
The study does not advocate coercive birth restrictions. The researchers propose a voluntary approach based on broader access to contraception and reproductive healthcare, education for girls, and women’s ability to decide the size of their families. According to data cited in the paper, more than 200 million women worldwide still lack access to the family planning services they need.
However, a smaller population alone would not solve the problem without changes in consumption habits. The authors emphasize that the wealthiest countries use significantly more resources: high-income nations consume, on average, 13 times more energy per person than low-income countries.
Earlier, Qazinform News Agency reported that plastic leakage into the environment across Southeast Asia, China, Japan and South Korea could rise by nearly 70% from 2022 levels to 14.1 million tons annually by 2050 without effective action.
