November 15, 2022, will be a landmark date for humanity. In 12 days, the United Nations projects that the global population will exceed eight billion for the first time. Coming only 11 years after the “day of seven billion” and with slowing population growth delaying the expected nine billion marker until 2037, this event will lead many to ask: is a larger global population a good or bad thing?

The implications are fiercely contested. Two thirds of humanity live in a country or area with a fertility rate below the 2.1 births per woman required for population stability. The global population is projected to peak at 10.4 billion in the 2080s. An ageing West is already grappling with falling economic dynamism and the realisation that welfare states are unsustainable as the retired grow rapidly relative to workers. Several countries are contemplating tax incentives to encourage births.

In contrast, prominent environmentalists think a growing population threatens the planet. “All of our environmental problems become easier to solve with fewer people,” Sir David Attenborough has said. UK youngsters agree. A YouGov poll found that 46 per cent of those who were able to have children would consider, or were already, limiting how many children they have “to address climate change”. Just 31 per cent said they would ignore this concern.

The UN is correct in the banal adjudication that “the relationship between population growth and sustainable development is complex”. Yet before doom and gloom merchants dominate discussions, it’s worth noting who has been most wrong on the effect of population growth. Malthusian thinkers — those pessimists who think that a growing population’s demands will overstretch and sometimes exhaust the Earth’s resources, creating poverty and conflict — have been the most off-base for two centuries.

The human population has risen from one billion to eight billion since 1800. During that time, the share living in absolute poverty has declined from more than 90 per cent to less than 10 per cent, with average real incomes per capita increasing 12-fold. This is not due to the unsustainable pillaging of the Earth’s bounty. If we were exhausting resources, economics suggests we should be seeing soaring prices for materials such as rubber, cotton, aluminium, platinum, lead, or wheat. A new book, Superabundance, by my colleague Marian Tupy and the economist Gale Pooley, reveals the opposite.

The World Bank’s series of 37 commodities includes the resources above in addition to tea, soya beans, platinum, zinc, natural gas and more. The average “time price” of these goods fell globally by 83 per cent between 1960 and 2018, meaning the average amount of time that humans must work to obtain these products has collapsed.

All bar gold and crude oil have become cheaper; 18 by 80 per cent or more. Instead of more mouths worsening scarcity, their supply has instead outstripped rising demand, producing a “superabundance”. Tupy and Pooley find this story consistent across time and data sets.

How to explain this? A larger population certainly increases the demand for Earth’s commodities, pushing up prices for a fixed supply. Ultimately, though, supply is not “fixed”. A larger population provides a critical economic input: more human brains.

This intellectual fuel, coupled with the freedom to innovate where prices provide incentives, has led to humans harnessing alternative resources, developing combinations, inventing novel extraction methods and new means of economising on use.

Many environmentalists claim that it is impossible to have infinite growth on a finite planet. But, as Tupy explains: “The Earth’s atoms may be fixed, but the possible combinations of those atoms are infinite.” A larger population certainly brings challenges, from ocean pollution to carbon emissions. To date, though, human innovation has outpaced the first-order effect of more people sapping Earth’s riches. As the “day of eight billion” nears, beware the usual doomsday predictions about parasitic humans running resources dry.