Are you worried about overpopulation?

A dear friend is very concerned that global overpopulation is making sustainable resource management impossible. A current example is the California drought and water crisis. Because this subject is definitely not intuitive, I thought I would share some resources that I outlined by email:

Regarding your sincere population worries – here are some possibly useful resources. First, the one hour BBC-produced talk by Swedish demographer Hans Rosling is an friendly introduction to  population dynamics BBC “Overpopulated”.

The fact that BBC funded such an expensively-produced mini-documentary reflects the reality that many people continue to accept the 1960s perspective voiced by Paul Erlich and The Club of Rome. This Malthusian view was what I believed through the 1990s. It was only when I had time to study current population research that I realized I was very out of date.

For a more in-depth, but still easy to follow lecture, see mathematical biologist Joel Cohen’s Floating University segment Malthus Miffed. I think it would be difficult to digest Dr. Cohen and still be frightened about runaway long term population growth.

That said, we also know very well how to make population growth a problem again. If we hobble the engine of economic growth – especially the improvement of the incomes of the very poor in Africa and Asia, then we could blow through the 9 Billion U.N. population forecast (plus 2.5 Billion from 2014).

It could happen – consider how badly the 2008 global financial crisis was handled by politicians and central bankers. “Never underestimate a politician”. But even with the below trend growth that we observe in the USA and EU, the Bottom Two Billion is transitioning out of subsistence farming to urban progress. Continuing that progress is essential to the forecasts of better health leading to falling family sizes.

For more well-written background on the subject please read the recent survey article by Stanford’s Martin Lewis: Population Bomb? So Wrong. E.g., did you know that India and America fall into the same (TFR of 2 to 3) fertility bucket? Excerpt:

India’s declining fertility rate, now only slightly higher than that of the United States, is part of a global trend of lower population growth. Yet the media and many educated Americans have entirely missed this major development, instead sticking to erroneous perceptions about inexorable global population growth that continue to fuel panicked rhetoric about everything from environmental degradation and immigration to food and resource scarcity.

In a recent exercise, most of my students believed that India’s total fertility rate (TFR) was twice that of the United States. Many of my colleagues believed the same. In actuality, it is only 2.5, barely above the estimated U.S. rate of 2.1 in 2011, and essentially the replacement level. (A more recent study now pegs U.S. fertility at 1.93.) Still, from a global perspective, India and the United States fall in the same general fertility category, as can be seen in the map below.

Click to embiggen

In today’s world, high fertility rates are increasingly confined to tropical Africa. Birthrates in most so-called Third World countries have dropped precipitously, and some are now well below the replacement rate. Chile (1.85), Brazil (1.81), and Thailand (1.56) now have lower birthrates than France (2.0), Norway (1.95), and Sweden (1.98).

To be sure, moderately elevated fertility is still a problem in several densely populated countries of Asia and Latin America, such as the Philippines (3.1) and Guatemala (3.92).

Click to embiggen

I highly recommend a careful read of the Martin Lewis essay. E.g., the surprising correlation of TV viewing with TFR (is it causation or coincidence?).

So, that’s a summary of the perspective of academics who make a living worrying about population growth. But we also know very well how to make population growth a problem again. One way is to destroy the engine of economic growth – especially the ongoing improvement of the incomes of the very poor in Africa and Asia. If we did that, then we could blow through the U.N. 2050 forecast of 9 to 10B population.

It could happen – consider how badly the 2008 global financial crisis was handled by politicians and central bankers. “Never underestimate a politician”. But even with the below trend growth that we observe in the USA and EU, the Bottom Billion is transitioning out of subsistence farming to urban progress. That progress is essential to the forecasts of better health leading to falling family sizes.

Another way is to allow climate change to develop so much momentum that there are no feasible mitigation or adaption strategies. That is sure to diminish incomes & health in the vulnerable populations. And those are the key drivers of the population turnaround.

Dear reader, if you know of other quality resources please provide the links. And especially please mention any peer-reviewed work that contradicts the consensus view reflected by professors Rosling,  Cohen and Lewis.

Target the planning laws not the one per cent

 

At FT.com Robin Harding (@RobinBHarding) has a very smart essay on the true cause of high real estate prices. This is a wide-spread disease, with familar standout cases such as London and San Francisco. Excerpt (emphasis mine):

About 40 per cent of the stated wealth of the UK – more than £3tn – does not exist. It is a terrible illusion. For the US the figure is about 12.5 per cent of total wealth, or $10tn, and growing fast.

The “assets” in question are what planning or zoning restrictions have added to house prices. They are the ransom that renters and recent buyers must pay to existing homeowners – whose homes the rules protect – for use of an artificially limited stock of housing. So severe have those restrictions become that the value of the ransom runs into the trillions.

Wealth of this kind is far more destructive than the alleged sins of the top 1 per cent. It is wealth created not by improving our living standards but by making them worse; by building too few houses in London and San Francisco, not too many. It is not earned by skill or effort. It is taken directly from the pockets of some – the young, especially those who were born poor – and transferred to others via political regulations on building. This is not wealth, this is plunder.

[...snip...]

You might think the rise in house prices reflects a natural scarcity of land. Britain is a small island; San Francisco sits on a narrow peninsula. However, the best available studies suggest that the vast majority of this rise in urban house and land prices reflects not natural scarcity but planning restrictions.

A clever 2005 study by American economists Edward Glaeser and Joseph Gyourko compares the price of an extra square foot of land attached to a house (a slightly bigger back yard, perhaps) with the average price of a square foot of land under a house in the same city. If the problem is a natural shortage of land, the two prices should both be high because it is profitable to build on the back yards until the two prices converge.

That is not what happens, however. In the cities of coastal California, the average price of urban land is 10 times the price of land in a back yard because zoning laws make it impossible to turn one into the other. In Los Angeles, the price of the extra square foot on the garden was $2.60 while the average price of urban land was $30.44. In San Francisco, the back yard land was worth $7.84 per square foot, versus $63.72 on average for the same lot.

The ratio of these two figures – as much as 10 to 1 – suggests only 10 per cent of the value of land in expensive cities is due to its natural scarcity. The rest is planning restrictions.

Paul Cheshire and Christian Hilber at the London School of Economics applied the same trick to British and European offices in 2006, with terrifying results. For the well-heeled West End of London, the cost of planning restrictions was eight times the cost of actually building an office. In Birmingham, it was 2.5 times the cost of building the office. This was not because land in the West Midlands is desperately scarce – just land you are allowed to build on is scarce.

We have many examples of localities that have avoided the housing-tax (Austin, Houston, Dallas). However, I don’t know of any cases where the populace has chosen to tear down the restrictions on building. There are powerful incentives for the present property owners to prefer that prices keep climbing.

Politician are not keen to educate the populace about the full cost of their preference for building restrictions. E.g., the total economic loss caused by preventing workers from moving from relatively low to relatively high productivity areas. We know that a Haitian taxi driver’s productivity improves by roughly 10x if she can move to New York. Same job, but her productivity is automatically so much higher because the value of her service is proportionately higher. The same applies to a software developer moving from Oklahoma to San Francisco.

My Haitian taxi driver case illustrates that building restrictions have costs similar to immigration barriers. Progressives are more likely to recognize the need for immigration reform, whilst vigorously “protecting” their Manhattan or Palo Alto neighborhoods. The terrible costs of these “protections” weigh most heavily on the poorer demographics. Robin closes with this:

These rules have added billions and billions of dollars to the price of housing, money that must be paid to those who already own houses by those who do not. If we want to make society fairer and more equal, just let people build.

Hans Rosling: DON’T PANIC — The Facts About Population

Help us cross the river of myths

Hans Rosling is a Swedish development economist, and for very good reasons, a TED superstar. The captioned one hour documentary was on BBC November 2013. His Gapminder Foundation is a data analysis and presentation goldmine – you can get a self-directed education there.

For the cram course see 200 Countries, 200 Years, 4 Minutes

Instead of studying history one year at the university, you can watch this video for less than five minutes.

Joel Cohen: Malthus Miffed: Are People the Problem, the Solution, or Both?

I highly recommend that you inspect Floating University’s Great Big Ideas: An Entire Undergraduate Education While Standing on One Foot. 

In the Fall of 2011 Big Think teamed up with the Jack Parker Corporation to launch The Floating University, an online educational initiative that debuted at Harvard University, Yale University, and Bard College. Seeking to upset the status quo, evolve the structure of higher education, and democratize access to the world’s best thinkers, FU’s inaugural course, Great Big Ideas, became the most requested class at all three schools where it was offered.(…snip…)

There are twelve lectures, each taught by a leader in the field who is also a great teacher. The first lecture of the series is the captioned Malthus Miffed by Joel Cohen, a mathematical biologist and a professor of populations. It is a suitable topic for the first lecture because an understanding of demography is one of the foundations for understanding how the world works, and especially what policies are likely to succeed (e.g., immigration, development, climate).

Prof. Cohen really is a great teacher – a skill achieved by investing a lot of energy in developing the craft, including practice. Even if you don’t think you are interested in demographics I predict you will be glued to your screen for the duration of this lecture. The course package includes Readings and Discussion Questions. 

Enjoy!

Mark Lynas: Using the tools of biotechnology to advance Borlaug’s legacy

Don’t miss the recent keynote speech by Mark Lynas to the Borlaug Global Rust Initiative 2013 Technical Workshop, New Delhi. Norman Borlaug would be proud. Excerpts:

We are gathered here today, under the aegis of an international collaboration that bears his name, to continue Borlaug’s lifelong battle with wheat rust. Rust wiped out his family farm’s wheat when he was a boy, and rust was the reason Borlaug initially established the research station in Sonora.

As we all know, he and his colleagues succeeded eventually in defeating wheat stem rust for many decades, until the emergence of the resistant race Ug99 at the very end of the last century.

Although the progress of Ug99 has not been as dramatic as initially feared, susceptible wheat is still being grown all over the world, and forms a mainstay of humanity’s food supply today. A fifth of all our calories come from wheat, and the global harvest is nearly 700 million tonnes per year.

While European wheat growers keep stem rust at bay with liberal applications of fungicide, this is neither ecologically sustainable nor financially desirable over the longer term.

In south and east Asia, meanwhile, both of which produce more wheat than the whole of North America, most growers cannot afford or do not have access to fungicides.

Billions of people therefore depend on susceptible wheat varieties that are sitting ducks, waiting for an epidemic of Ug99 to be blown over on the winds from the Middle East and Africa.

I was given the mandate to talk today about ‘Using the tools of biotechnology to advance Borlaug’s legacy’, and I cannot imagine a more appropriate area where this applies than the question of tackling wheat stem rust.

Borlaug was an unusual revolutionary in that he didn’t want his revolution to stop with him. He was a lifelong advocate of innovation – and a staunch supporter of biotechnology as the promising new frontier for plant breeding.

You can see why. By today’s standards, Borlaug had to work blind, using guesswork, chance and a lengthy process of elimination with thousands upon thousands of wheat crosses to try to get just the right genetic combination.

I cannot imagine a better embodiment of Norman Borlaug’s philosophy than this successful joint effort.

**************

But unfortunately the progress of good science runs up against the hard rock of bad politics. As perhaps the world’s most political food crop, by virtue of its very nature in supplying our daily bread, wheat has so far been locked out of the biotechnology revolution.

Although many new wheats have been developed using recombinant DNA and even tested in field trials, not a single one has ever been made available to farmers – not because there was anything wrong with the new varieties, but solely because of the worldwide cloud of fear and superstition that surrounds the use of genetic engineering.

Thus, the most powerful tools offered by modern molecular biotechnology must seemingly be permanently discarded – not because of any rational assessment of risks and benefits – but because a tide of anti-science activism has drowned scientists and governments around the whole world in a tsunami of lies.

The importance of being urban

Don't miss the latest from Ryan Avent at the Economist Free Exchange:

WHILE Europe's austerity-minded governments and inflation-averse central bank must take much of the credit for the euro area's current economic problems, the crisis has been fanned by failures of regulatory reform and integration that have made adjustment much harder than it needs to be. Those failures also operated prior to the crisis, contributing to growth in imbalances, and without much more in the way of structural reform they will continue to be an economic albatross when the crisis is finally put to rest.

This week's Free exchange column looks at an underappreciated way in which regulatory burdens and incomplete integration have prevented the euro area from taking full advantage of the size of its market and growing richer: by constraining the growth of its cities:

Although America and the euro zone have similar total populations, America’s 50 largest metropolitan areas are home to 164m people, compared with just 102m in the euro area. This striking disparity has big consequences.

Differences in metropolitan populations may help explain gaps in productivity and incomes. Western Europe’s per-person GDP is 72% of America’s, on a purchasing-power-parity basis. A recent study by the McKinsey Global Institute, the consultancy’s research arm, reckons that some three-quarters of this gap can be chalked up to Europe’s relatively diminutive cities. More Americans than Europeans live in big cities: there is a particular divergence in the size each region’s “middleweight” cities, those that teem just a little less than the likes of New York and Paris (see chart). And the premium earned by Americans in large cities relative to those in the countryside is larger than that earned by urban Europeans.

In highly skilled societies, bigger cities are associated with higher levels of productivity and income, the column explains. This seems to be due to the ways in which cities facilitate innovation in an age of rapidly increasing economic and technological complexity. Prosperity now requires lots of skilled individuals in reasonably close proximity to each other, to learn from and occasionally partner with as part of the process of coming up with and spreading new ideas. America appears to be better able than Europe to accomplish this across a wide range of places.

But why? The piece explains:

Regulatory barriers to growth may be to blame. Tight zoning rules limit housing supply and raise prices by driving a wedge between construction costs and market prices. This “regulatory tax” amounts to over 300% in the office markets in Frankfurt, Paris and Milan, according to a 2008 study by Paul Cheshire and Christian Hilber of the London School of Economics, but is just 50% in Manhattan and, in effect, zero in fast-growing places like Houston. Taxes that add to transaction costs also help explain low European mobility.

(… Snip…)

Norman Borlaug: “World Bank fear of green political pressure in Washington became the single biggest obstacle to feeding Africa”

While John Tierney wrote this piece in 2008, it is just as relevant in 2012. If this surprises you, then I recommend you also read Attention Whole Foods Shoppers by Robert Paarlberg.

I hope you will be persuaded to try to enlighten your “green” neighbors – that they are part of the problem, not part of the solution:

Farmers and consumers in poor countries are now paying the price for decisions made by well-fed Westerners, as reported by my colleagues Keith Bradsher and Andrew Martin in their front-page article on cutbacks in financing for agricultural research. They explain how the Green Revolution faltered after Western governments and agencies slashed funds for agricultural research, partly to shift money to other areas, like environmental projects, and partly because of opposition to high-yield agriculture from advocacy groups.

If you find it hard to imagine how anyone could be opposed to growing more food for poor people, read Gregg Easterbrook’s 1997 Atlantic Monthly article on Norman Borlaug, the agronomist whose achievements through the Green Revolution may have saved a billion lives. Mr. Easterbrook wrote:

The Ford and Rockefeller Foundations and the World Bank, once sponsors of his work, have recently given Borlaug the cold shoulder. Funding institutions have also cut support for the International Maize and Wheat Center — located in Mexico and known by its Spanish acronym, CIMMYT — where Borlaug helped to develop the high-yield, low-pesticide dwarf wheat upon which a substantial portion of the world’s population now depends for sustenance. And though Borlaug’s achievements are arguably the greatest that Ford or Rockefeller has ever funded, both foundations have retreated from the last effort of Borlaug’s long life: the attempt to bring high-yield agriculture to Africa.

Pressure from environmentalists was the chief reason for these cutbacks, Mr. Easterbrook reported:

[By]the 1980s finding fault with high-yield agriculture had become fashionable. Environmentalists began to tell the Ford and Rockefeller Foundations and Western governments that high-yield techniques would despoil the developing world. As Borlaug turned his attention to high-yield projects for Africa, where mass starvation still seemed a plausible threat, some green organizations became determined to stop him there. “The environmental community in the 1980s went crazy pressuring the donor countries and the big foundations not to support ideas like inorganic fertilizers for Africa,” says David Seckler, the director of the International Irrigation Management Institute.

Environmental lobbyists persuaded the Ford Foundation and the World Bank to back off from most African agriculture projects. The Rockefeller Foundation largely backed away too — though it might have in any case, because it was shifting toward an emphasis on biotechnological agricultural research. “World Bank fear of green political pressure in Washington became the single biggest obstacle to feeding Africa,” Borlaug says. The green parties of Western Europe persuaded most of their governments to stop supplying fertilizer to Africa; an exception was Norway, which has a large crown corporation that makes fertilizer and avidly promotes its use. Borlaug, once an honored presence at the Ford and Rockefeller Foundations, became, he says, “a tar baby to them politically, because all the ideas the greenies couldn’t stand were sticking to me.”

Dr. Borlaug didn’t disguise his anger in summarizing his feelings about greens to Mr. Easterbrook:

“Some of the environmental lobbyists of the Western nations are the salt of the earth, but many of them are elitists. They’ve never experienced the physical sensation of hunger. They do their lobbying from comfortable office suites in Washington or Brussels. If they lived just one month amid the misery of the developing world, as I have for fifty years, they’d be crying out for tractors and fertilizer and irrigation canals and be outraged that fashionable elitists back home were trying to deny them these things.”

(…)UPDATE: 

My colleague Andy Revkin notes parallels in financing for energy as well as agricultural research: short-sightedness seems to reign.

 Continue reading John Tierney.

Doubling Global Food Supply by Engineering Food for All

Regarding food supply and demand: in the next forty years the global demand for food will double. We are already utilizing 35% of the planet’s ice-free land area for agriculture, an area 60 times that of all cities and suburbs. The supply to balance that demand doubling needs to be achieved at affordable prices, on a per calorie basis, using less land, less water, less nitrogen runoff, less pesticide and a smaller carbon footprint.

In a new op-ed at the New York Times, Pennsylvania State University biology professor Nina V. Fedoroff explains how we can do this:

FOOD prices are at record highs and the ranks of the hungry are swelling once again. A warming climate is beginning to nibble at crop yields worldwide. The United Nations predicts that there will be one to three billion more people to feed by midcentury.

Yet even as the Obama administration says it wants to stimulate innovation by eliminating unnecessary regulations, the Environmental Protection Agency wants to require even more data on genetically modified crops, which have been improved using technology with great promise and a track record of safety. The process for approving these crops has become so costly and burdensome that it is choking off innovation.

Civilization depends on our expanding ability to produce food efficiently, which has markedly accelerated thanks to science and technology. The use of chemicals for fertilization and for pest and disease control, the induction of beneficial mutations in plants with chemicals or radiation to improve yields, and the mechanization of agriculture have all increased the amount of food that can be grown on each acre of land by as much as 10 times in the last 100 years.

These extraordinary increases must be doubled by 2050 if we are to continue to feed an expanding population. As people around the world become more affluent, they are demanding diets richer in animal protein, which will require ever more robust feed crop yields to sustain.

New molecular methods that add or modify genes can protect plants from diseases and pests and improve crops in ways that are both more environmentally benign and beyond the capability of older methods. This is because the gene modifications are crafted based on knowledge of what genes do, in contrast to the shotgun approach of traditional breeding or using chemicals or radiation to induce mutations. The results have been spectacular.

For example, genetically modified crops containing an extra gene that confers resistance to certain insects require much less pesticide. This is good for the environment because toxic pesticides decrease the supply of food for birds and run off the land to poison rivers, lakes and oceans.

The rapid adoption of genetically modified herbicide-tolerant soybeans has made it easier for farmers to park their plows and forgo tilling for weed control. No-till farming is more sustainable and environmentally benign because it decreases soil erosion and shrinks agriculture’s carbon footprint.

In 2010, crops modified by molecular methods were grown in 29 countries on more than 360 million acres. Of the 15.4 million farmers growing these crops, 90 percent are poor, with small operations. The reason farmers turn to genetically modified crops is simple: yields increase and costs decrease.

Myths about the dire effects of genetically modified foods on health and the environment abound, but they have not held up to scientific scrutiny. And, although many concerns have been expressed about the potential for unexpected consequences, the unexpected effects that have been observed so far have been benign. Contamination by carcinogenic fungal toxins, for example, is as much as 90 percent lower in insect-resistant genetically modified corn than in nonmodified corn. This is because the fungi that make the toxins follow insects boring into the plants. No insect holes, no fungi, no toxins.

Yet today we have only a handful of genetically modified crops, primarily soybeans, corn, canola and cotton. All are commodity crops mainly used for feed or fiber and all were developed by big biotech companies. Only big companies can muster the money necessary to navigate the regulatory thicket woven by the government’s three oversight agencies: the E.P.A., the Department of Agriculture and the Food and Drug Administration.

Decades ago, when molecular approaches to plant improvement were relatively new, there was some rationale for a cautious approach.

But now the evidence is in. These crop modification methods are not dangerous. The European Union has spent more than $425 million studying the safety of genetically modified crops over the past 25 years. Its recent, lengthy report on the matter can be summarized in one sentence: Crop modification by molecular methods is no more dangerous than crop modification by other methods. Serious scientific bodies that have analyzed the issue, including the National Academy of Sciences and the British Royal Society, have come to the same conclusion.

It is time to relieve the regulatory burden slowing down the development of genetically modified crops. The three United States regulatory agencies need to develop a single set of requirements and focus solely on the hazards — if any — posed by new traits.

And above all, the government needs to stop regulating genetic modifications for which there is no scientifically credible evidence of harm.

Professor Fedoroff was president of the AAAS when she wrote this.

The evidence from developing countries already shows us that doubling of demand will include increased demand for meat (which requires more land and water than grain calories). So please tell me how we are going to achieve this revolution in agricultural productivity without utilizing all the available science and innovation? Must we continue hobbled like children in a sack-race?

Can marine fisheries and aquaculture meet fish demand from a growing human population in a changing climate?

These researchers conclude “Yes” to the captioned query:

Gorka Merinoa, Manuel Barangea, Julia L. Blanchardb, James Harlec, Robert Holmesa, Icarus Allena, Edward H. Allisond, Marie Caroline Badjeckd, Nicholas K. Dulvye, Jason Holtc, Simon Jenningsf, g, Christian Mullonh, Lynda D. Rodwelli

Essential fisheries management changes include switching feed from wild fish meal. Abstract:

Expansion in the world’s human population and economic development will increase future demand for fish products. As global fisheries yield is constrained by ecosystems productivity and management effectiveness, per capita fish consumption can only be maintained or increased if aquaculture makes an increasing contribution to the volume and stability of global fish supplies. Here, we use predictions of changes in global and regional climate (according to IPCC emissions scenario A1B), marine ecosystem and fisheries production estimates from high resolution regional models, human population size estimates from United Nations prospects, fishmeal and oil price estimations, and projections of the technological development in aquaculture feed technology, to investigate the feasibility of sustaining current and increased per capita fish consumption rates in 2050. We conclude that meeting current and larger consumption rates is feasible, despite a growing population and the impacts of climate change on potential fisheries production, but only if fish resources are managed sustainably and the animal feeds industry reduces its reliance on wild fish. Ineffective fisheries management and rising fishmeal prices driven by greater demand could, however, compromise future aquaculture production and the availability of fish products.

The article is unfortunately behind the bloody Elsevier paywall.

Economic and population growth not need be a zero sum game

I’m surprised that the Royal Society got it so wrong – this reads like a Paul Erlich/Limits to Growth product (Prof. Erlich did give testimony to the committee). But Mark Lynas and Leo Hickman have the science right. Here’s a taster:

The Royal Society – Britain’s premier scientific institution – has just released a major report called People and the Planet, arguing that per capital resource consumption in the richest parts of the world needs to come down dramatically if the poorest 1.3 billion are to be lifted out of extreme poverty whilst protecting the Earth’s environment from irreparable harm. (Do join Leo Hickman’s debate on the Guardian site here, and my thanks to him for prompting this piece.)

I wouldn’t argue with most of the data underpinning this report, but I do have problems with some of the assumptions. The first is that population growth is necessarily a bad thing, and that there is therefore a pressing need to reduce the rate of growth in developing countries. The report states early on:

“At a time when so many people remain impoverished and natural resources are becoming increasingly scarce, continued population growth is cause for concern.”

What it fails to acknowledge however is that population growth is correlated with economic growth – and therefore if developing countries are to continue to escape from poverty then reducing their rate of population growth should not be the initial priority. In a recent blogpost the World Bank’s Wolfgang Fengler starts by reminding us:

Africa’s population is rising rapidly and will most likely double its population by 2050. Depending on the source of data, Africa will soon pass 1 billion people (and it may already have) and could reach up to 2 billion people by 2050 [ I am using the UN’s 2009 World Population Prospects, which projects Africa to exceed 1.7 billion by 2050 based on sharply declining fertility rates]. This makes it the fastest growing continent and Africa’s rapid growth will also shift the global population balance.

Sounds scary. But what no-one mentions is that in terms of population density Western Europe is far more over-populated than Africa:

If we look at Western Europe – where I come from – there are on average 170 people living on each square km. In Sub-Saharan Africa there are only 70 today. This gap will narrow in the next decades but even by 2050, Western Europe is expected to be more densely populated than Africa.

He then concludes:

…population growth and urbanization go together, and economic development is closely correlated with urbanization. Rich countries are urban countries.  No country has ever reached high income levels with low urbanization. And this is critical for achieving sustained growth because large urban centers allow for innovation and increase economies of scale. Companies can produce goods in larger numbers and more cheaply, serving a larger number of low-income customers.

Population growth may therefore put us on the edge of a “golden age of development” for Africa – hardly the message from the gloomy Royal Society report. As the excellent book Emerging Africa, by Steven Radelet, shows, seventeen sub-Saharan African countries have seen sustained economic growth since 1995, vastly improving their prospects and – I suspect – further reducing fertility rates in the process.

Whilst using a lot of dark language about increasing numbers of humans globally, the report nowhere acknowledges that the current median level of total worldwide fertility has fallen dramatically from 5.6 in the 1970s to only 2.4 today. In other words we are already close to natural replacement levels in terms of total fertility – the reason that the absolute population will continue to grow to 9 billion or more is that more children are living long enough have their own children. To my mind a reduction in infant mortality and an increase in life expectancy are self-evidently good and desirable – and their impact on world population levels should be celebrated, not bemoaned.

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