January 09, 2017

Why birthrates may not continue dropping forever and overall population could increase and clean energy and advanced agriculture could support the population

A poster to ycombinator looked at birthrates and living standards to draw the conclusion that rising living standards will drive the world to a population peak in 2065 Nextbigfuture disagrees with the projection for population and also disagrees with the assumption of perpetually dropping birthrates.

Why World population will likely be higher than 9.75 billion in 2050

1. The UN has been revising its population projections higher for the last 15-20 years. They have kept expecting the birthrate in Africa to decline faster than it actually has

2. The population census in African and many other poorer countries tend to be out of date. Which means the most recent census is old and inaccurate. This tends to mean an undercount. China likely has an undercount of 10-30 million because of the second and third child being hidden because of the one child policy. World population is likely already 7.5 billion now and not 7.3 billion.

While population projections are certainly educated guesses, they can be suprisingly accurate. An evaluation of a series of United Nations population projections between the 1950s and 1990s found that all but one had a margin of error of less than 4%.

In Africa, however, the quality of data can pose significant problems. “Some [African] countries have very few censuses, and a number of censuses are of doubtful accuracy,” Professor Rob Dorrington, Professor of Actuarial Science at the University of Cape Town, told Africa Check.

Countries like Eritrea, South Sudan and the Democratic Republic of the Congo did not conduct population censuses between 2005 and 2014, as required by the UN for their 2010 round of projections. This year Angola conducted its first national census in 30 years, Dr Mady Biaye, Technical Advisor for East and Southern Africa at the United Nations Population Fund told Africa Check.

In Nigeria the country’s census figures have been the subject of controversy for decades. Accusations of rigging date back to the 1950s and have continued unabated under military and civilian regime. It is not possible to give a firmly reliable estimate for the total population of Nigeria. The 2006 census cited a population of around 140 million. The most commonly cited figures today are from the World Bank, and they are extrapolated from that headcount. It reports that 168 million people were living in Nigeria in 2012. These figures are just guesstimates. Nobody knows whether the population is 120 million, 150 million, 200 million – no Nigerian, not the NPC, the UN, the World Bank. [Africa Check a non-partisan organisation which promotes accuracy in public debate and the media. Twitter @AfricaCheck and www.africacheck.org]

3. China will move completely away from population control by 2020 and shift to encouraging more children. This will likely mean that China's population will not fall much after 2030.

4. There will be more improvements in medicine that will further increase life expectancy.

What could boost population growth ?

* radical life extension for fewer deaths
* lower cost and more effective in vitro fertilization. About 16-20% of couples who want children cannot have them
* if technology in the post-2050 timeframe delivers cheap access to space (orbit and solar system), material abundance from nanotechnology and other technology and abundant energy from nuclear fusion, molten salt fission, advanced solar power and space based solar power, then there could be population and wealth growth without adverse impacts even if population increased hundreds of times beyond current levels

Birthrates in developed countries can bounce back because children of large families tend to have larger families.









Business as usual improvements to agriculture (better crops with genetically guided plant breeding, precision agriculture and other measures) we can reduce water usage in half and increase crop yields by double over 2-3 decades.

Greenhouses can use 1/6th the water and 1/10th the land to produce the same amount of crop.

Hydroponics can use 1/20th the water. Aeroponics used 65% less water than hydroponics. NASA also concluded that aeroponically grown plants requires ¼ the nutrient input compared to hydroponics

There have been proposals for large scale hydroponics adoption.

Simplified hydroponics was developed in the early 1980’s in Colombia.These projects were a success as on average a single garden made a profit of $90 in two to three months with the initial investment being $355. Since 1984, projects have been implemented in 12 Latin American and African countries, mostly funded by the UNDP and the UN FAO.

Costs for building gardens for Asia tropical areas

Of the estimated 790 million people classified as hungry in 2000, 525 million lived in Asian nations (UN FAO, 2000).
This is a rough estimate of what Bradley and Marulanda (2000) estimated would be the cost of setting up a hydroponic garden in Tropical Asia.

The total number of beneficiaries would be 232 million for 50 million gardens, each garden accommodating an average family unit of 4. Initial cost of setting up a garden amount to $355 including a year supply of nutrients and seeds. The total cost of implementing this plan in Tropical Asia is 20 billion dollars but it generates a revenue of 135 billion per year. Income from each garden would be about $329-1405 per year.

Indoor and vertical farming have been proposed. Indoor farming can produce crops year-round. All-season farming multiplies the productivity of the farmed surface by a factor of 4 to 6 depending on the crop. With some crops, such as strawberries, the factor may be as high as 30.

The factory mass produced China Broad Group skyscrapers could drastically reduce the cost of buildings for vertical farming as well. Broad Group buildings can be seven times cheaper than the square foot cost of skyscrapers like the Burj Kahlifa (current world's tallest building.

Despommier suggests that, if dwarf versions of certain crops are used (e.g. dwarf wheat developed by NASA, which is smaller in size but richer in nutrients), year-round crops, and "stacker" plant holders are accounted for, a 30-story building with a base of a building block (5 acres (20,000 m2)) would yield a yearly crop analogous to that of 2,400 acres (9.7 km2) of traditional farming.

Spending about $16 trillion, humanity could enclose agriculture and radically densify and reduce the agricultural footprint. It could be done for about 20-25% of the world's current GDP in one year. If this was spread out over ten years then it would be affordable if absolutely needed to reduce water and land usage.


The World could sustainable scale up nuclear fission technology with deep burn modular factory mass produced nuclear reactors and achieve 100 times the current world energy production.


One hundred billion people could live at a Western standard of living (10 kilowatts) if they had clean energy, enough food, water and the only concern was the level of waste heat.

A lot of people are worried about global warming.

From now until 2040, if you want to have a 0.75 degree celsius increase instead of a possible 1.25 degree celsius temperature increase then soot mitigation should be targeted. Currently discussed measures against CO2 would not have a noticeable effect until around 2070. Soot mitigation is about ten to twenty times cheaper than CO2 mitigation.

If Global Warming got to be serious we have Cheap Failsafe geoengineering options

The cost to construct a Stratospheric Shield with a pumping capacity of 100,000 tons a year of sulfur dioxide would be roughly $24 million, including transportation and assembly. Annual operating costs would run approximately $10 million. The system would use only technologies and materials that already exist—although some improvements may be needed to existing atomizer technology in order to achieve wide sprays of nanometer-scale sulfur dioxide particles and to prevent the particles from coalescing into larger droplets. Even if these cost estimates are off by a factor of 10 (and we think that is unlikely), this work appears to remove cost as an obstacle to cooling an overheated planet by technological means.

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