John Bongaarts at the Population Council thinks Climate Change has a good chance of limiting human Population but he is wrong

According to the new analysis by researchers at the United Nations and several academic institutions, there is an 80 percent chance that the world’s population, now 7.2 billion, won’t stop at nine billion in 2050, but will instead be between 9.6 billion and 12.3 billion by 2100. The researchers increased their estimates after noting persistent high birth rates and faster-than-expected progress in combatting HIV/AIDS in Africa. [Journal Science - World population stabilization unlikely this century]

Technology Review David Talbot says the prediction’s reliability is debatable, given that it does not take into account future hardships a large population would likely face. It doesn’t take into account the effects of climate change, food shortages, disease, or conflict. The study take into account that population growth could trigger deadly calamities like food shortages, war, and disease even without climate change, says John Bongaarts, vice president and distinguished scholar at the Population Council, a think tank and research organization based in New York City.

Wolfgang Lutz, director of the Vienna Institute of Demography, says, his newest analysis still suggests a less-dire outcome. “Our most likely scenario comes out somewhat lower than the current United Nations projections,” and suggests population will peak at 9.4 billion around 2070 and start a slow decline to nine billion by the end of the century.

So Lutz at the Vienna Demography Institute calls a human population rising to 12 billion in 2100 a dire outcome. It would be dire if wars, food shortages, disease and climate change do not limit population ? Or if Africa does not see vastly increased usage of birth control ?



Birth rates are suppressed during big wars but studies show that there is an increase in birth rates after the war and population levels recover.

Birth rates and populations also bounce back after famines.

Bongaarts seems to be hoping or expecting permanent wars and famines.

Africa has more wars and famines than other places in the world. This is one of the reasons that the birth rates stay high. People are worried that they will lose children. So they have 5-6 kids hoping that 2-3 will survive. When survival rates are good then birth rates are low. A lot of wars and famine and hardship means that people will have more kids and not less and population will be higher. There would have to be a complete global collapse for the population to drop and stay down. Bongaarts underestimates what people can do.

Large scale fish farming and ocean management (iron fertilization of the ocean to boost fish).
Bongaarts does not realize that all of the CO2 emissions and climate effects are side effects of our civilization. This is happening without that as a goal. Of course the technology exists and can be developed for changing the climate and the oceans to what we want. It is about getting the most economic and efficient solutions.

Ocean Acidification can be mitigated

Climate change can be mitigated.

Correcting soot pollution is 20 times cheaper than fixing the CO2

The World can support one hundred billion living at western levels and expected improvements in agriculture, energy and water can easily handle 15-20 billion by 2100.


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Africa potential and challenges for increasing agricultural yield

[NY Times] Africa’s agricultural yields are less than half the global average, and about 25 percent of what they could potentially yield. Agricultural productivity in Africa is growing at about half the rate the population is growing. Africa has long been a continent of small farmers, half of them women, raising maize with no fertilizer, pesticide or irrigation, on a tiny plot with a hoe. Now the little these farmers have is endangered by drought. Climate change is making Africa’s weather more extreme and erratic. Africa loses about a fifth of its maize crop because of drought. In many years, the loss is near-total. A survey of farmers in 12 countries found that in the last decade, they averaged about three wipeout years. In 2000, the first seeds for drought-tolerant maize were planted in Malawi and Zimbabwe. Now three million farmers in 13 countries in Africa are using them. (All these strains are conventionally bred, not genetically modified.) “One drought is something that throws farmers back into poverty,” said Bänziger. “They lose everything. During a severe drought, a farmer may harvest 5 percent of the ears of a normal crop. With drought-tolerant maize, the farmer can get 50 percent. We want to get to the point where we can save every plant.” Pesticides and inorganic fertilizers are bad for the environment. But this is not an argument that anyone who eats in America should be making to African subsistence farmers. In 2006, an African Union Declaration on agriculture adopted the goal of 50 kilograms of fertilizer per hectare planted. At the time, Africa was using only eight kilos per hectare; America was using 120. Africa needs vastly more fertilizer use, not less. The Green Revolution failed in Africa for reasons that remain major obstacles today. Absent research, roads, storage, extension capacity, credit and subsidies — high-yield maize will produce little, or its gains will go only to wealthier farmers.

Nation Master shows that the lowest agricultural yields are in Africa [mainly 2008 statistics]. Below are kilograms cereal grain yields per hectare. Developed countries have about 6000+ kg per hectare and the world average is about 3500 kilograms per hectare.

Lighter green in the map means lower yield per hectare A lot of issues to get better. Fertilizer usage, local fertilizer production, irrigation, improved seeds and crops, roads

[UN] It is difficult to overestimate the importance of agriculture to Africa’s economic prospects. Some 65% of Africa’s labour force is engaged in agriculture, and the sector accounts for about 32% of the region’s GDP, according to the Alliance for a Green Revolution in Africa (AGRA), an independent organization advocating for improvements in Africa’s agriculture. According to the Food and Agriculture Organisation (FAO), growth in sub-Saharan agriculture employment accounted for half of all employment growth between 1999 and 2009. One important obstacle to increased productivity has been the steady deterioration of Africa’s soils, noted Mr. Amit Roy, the head of the International Fertilizer Development Centre (IFDC), a US-based institute that promotes agricultural advancement in developing countries. “When farmers plant the same fields season after season and cannot afford to replace the soil nutrients taken up by their crops, the soil is literally mined of life,” he says. An estimated 8 million tonnes of nutrients are depleted annually. Replenishing the nitrogen, potassium, phosphorus and other minerals absorbed by plants is therefore vital to keep crop yields from declining. Part of the answer lies in better farming methods, including expanding the range of crops grown, improving soil conservation practices and utilizing improved seeds and technology. But the key to launching a “revolution” in African agriculture, Mr. Roy told Africa Renewal, is much greater use of fertilizer. “Traditionally, African farmers use the slash-and-burn method,” he said. “They burn off a section of land and farm it for a season or two, then clear another plot and leave the old field fallow.” But population increases and growing land shortages have forced farmers to cultivate the same fields repeatedly, stripping the land of nutrients and resulting in smaller harvests and less income. Such pressures have also led farmers to clear land poorly suited for cultivation, which contributes to soil erosion and yields only marginal increases in harvests. An estimated 50,000 hectares of Africa’s forests and 60,000 hectares of savannah are lost to such methods annually — resulting in severe environmental degradation and contributing to the decline in agricultural production per capita. Yet evidence suggests that even modest increases in the use of fertilizer — whether nitrogen, phosphorous or potassium — can have dramatic results. In Ethiopia, one study found that just one bottle cap’s worth of chemical fertilizer on each plant increased millet yields exponentially. The technique, known as “micro-dosing,” is regarded as particularly appropriate for Africa’s small-scale farmers, because it reduces costs and avoids damage to fragile soils from excessive chemical use. One way to make chemical fertilizers more available and affordable is to increase local production. This can reduce costs, ease the pressure on foreign currency reserves and shorten the supply chain to farmers. Although Africa consumes only about 1% of global fertilizer production and currently produces even less, prospects for the commercial manufacture of fertilizers are good. Nitrogen is among the most common elements on earth, but converting it into use for plants is energy-intensive. West Africa’s vast and largely untapped natural gas resources, notes Mr. Roy, therefore make the region ideally suited for the manufacture of nitrogen fertilizer. Africa also has ample deposits of phosphorus and already exports the mineral to Chinese and Indian farmers. If these minerals can be utilized in local production, Africa would need to import only potassium fertilizer. But investment in fertilizer production will only come in response to increased demand from farmers, Mr. Roy asserts. Persuading Africa’s family farmers that purchasing fertilizer is worth the money and effort will require significant improvements in rural transport networks and infrastructure, an expanded network of rural farm suppliers and markets, and greater financial returns, including protection from price fluctuations and subsidized Northern competitors. NEPAD researchers have estimated the initial investment of irrigating 20 million more hectares of African farmland at $37 billion, with an additional $31 billion in operating costs through 2015. Rebuilding rural supply networks and marketing systems so farmers have the means and incentives to produce more is another major challenge. Government-run agriculture marketing boards used to perform some of these functions, providing stable prices, credit extension services, improved seeds and technology to local farmers. Mr. Roy says that expanding private sector involvement in rural marketing and supply activities is a long-term solution. But he acknowledges that high poverty rates in the countryside and the need for “public goods” like roads and markets give African governments a key role in creating incentives for private investment.

Background on the debate about the Green Revolution which saved over a billion lives Green Revolution sustainable options for ending hunger and poverty. Curse or Blessing? International Food Policy Research Institute If you liked this article, please give it a quick review on ycombinator or StumbleUpon. Thanks