....

Daily chart: Fleeing from Malthus | The Economist

Evoluções

The End of Population Growth - Sanjeev Sanyal - Project Syndicate

According to the United Nations’ Population Division, the world’s human population hit seven billion on October 31. As always happens whenever we approach such a milestone, this one has produced a spike in conferences, seminars, and learned articles, including the usual dire Malthusian predictions. After all, the UN forecasts that world population will rise to 9.3 billion in 2050 and surpass 10 billion by the end of this century. Such forecasts, however, misrepresent underlying demographic dynamics. The future we face is not one of too much population growth, but too little. Most countries conducted their national population census last year, and the data suggest that fertility rates are plunging in most of them. Birth rates have been low in developed countries for some time, but now they are falling rapidly in the majority of developing countries. Chinese, Russians, and Brazilians are no longer replacing themselves, while Indians are having far fewer children. Indeed, global fertility will fall to the replacement rate in a little more than a decade. Population may keep growing until mid-century, owing to rising longevity, but, reproductively speaking, our species should no longer be expanding.

É sobre o manifesto do assassino de Oslo ...

Muito interessante: as consequências societais das actuais tendências demográficas e a informação sobre a evolução demográfica recente dos países mussulmanos (ou só de alguns países mussulmanos?) que desconhecia. Depois há a leitura do manifesto do assassino.

A Murderer's Manifesto and Me - By Phillip Longman | Foreign Policy

Muslim countries, as I wish Breivik had taken time to absorb, are not immune to this phenomenon. As I've written many times, birth rates in Iran have come down so steeply that the Islamic Republic is aging far faster than any country in "old Europe." Meanwhile, birth rates in Tunisia and Lebanon are also below replacement levels, and many other Muslim countries, from Turkey to Morocco, are just on the cusp. For better or for worse, subreplacement fertility is now a condition of modernity, not just of the Western civilization that Breivik proclaims to love even as he slaughters its children. 

The vast demographic transformation overtaking the human race forces issues as contentious as they come: the role of women, religion, race and ethnicity, sex, marriage, birth control, the welfare state, and, before we are done, quite likely much harsher debates over who has a "duty to die" in an aging society. We still do face a population explosion, but mostly of old people, opening the way for generational conflict as well. Added to the mix are modern-day Malthusians who want to drive down human population to arrest global warming or just for the sake of "the planet." This century is likely to be dominated by eugenic thinking, and all the more so as different populations face the specter of demographic decline and environmental threat. Let us all try to keep our heads, maybe invest more in children, and remember our common humanity.

Sinistro

The Irish Economy » Blog Archive » The Irish “Masculinity Ratio”: "The current issue of The Economist has a leader on the growing imbalance between males and females in birth cohorts in China and India and some other countries. The sex ratio at birth, or “masculinity ratio”, is normally about 1.05. Amartya Sen and Ansley Coale drew attention to the high ratios emerging in China and India some twenty years ago. The ratio has continued to rise in these countries and has now reached 1.30 in some Chinese provinces."

É um dado a entrar em linha de conta na discussão da sustentibilidade da nossa civilização e da saúde da nossa espécie

"This figure shows the past and future world population as reported by the United Nations. For the future, ranges are shown based on the five different scenarios reported. Future population is one of the key uncertainties in determining future greenhouse gas emission scenarios. The scenarios considered by the Intergovernmental Panel on Climate Change have populations that range from 7 billion to 15 billion in the year 2100." 

File:Global Population.png - Global Warming Art 

Preocupações

Economist's View: "Transgressing Planetary Boundaries":

"Transgressing Planetary Boundaries, by Jeff Sachs, Scientific American: We are eating ourselves out of house and home. ... The green revolution that made grain production soar gave humanity some breathing space, but the continuing rise in population and demand for meat production is exhausting that buffer. ...  

Food production accounts for a third of all greenhouse gas emissions... Through the clearing of forestland, food production is also responsible for much of the loss of biodiversity. Chemical fertilizers cause massive depositions of nitrogen and phosphorus, which now destroy estuaries in hundreds of river systems and threaten ocean chemistry. Roughly 70 percent of worldwide water use goes to food production, which is implicated in groundwater depletion and ecologically destructive freshwater consumption from California to the Indo-Gangetic Plain to Central Asia to northern China."

Tese interessante ...

The Invisible Hand of Population Control - reasononline (via A Fistful of Euros):

"The chief goal of all other species is to turn food into offspring. More food means more offspring. It is this biological logic that underlies the perennial fears of human overpopulation. Most creatures live in environments that correspond to open access commons. Recent fertility trends strongly suggest that the simple biological model of human breeding is wrong, or at least, is wrong when the institutions that support economic freedom and the rule of law, e.g., markets, price stability, honest bureaucracies, security of private property, and the fair enforcement of contracts, are well-developed. Economic freedom and the rule of law are the equivalent of enclosing the open access breeding commons, causing parents to bear more and more of the costs of rearing children. In other words, economic freedom actually generates an invisible hand of population control."

PS: Qualificando esta tese, este apontamento do mesmo blogue: The invisible hand of letting people know who’s boss afoe A Fistful of Euros European Opinion 

Batatas

Da importância do cultivo da batata no crescimento da população mundial: Chris Blattman's Blog: You say potato, I say....

O apontamento cita um paper onde se refere que a batata seria responsável por 12 % do aumento da população, 22% do aumento no crescimento populacional, 47 % do aumento da urbanização, e 50 % do aumento no crescimento urbano.

PS: Sobre o mesmo: Potatoes, the fruit of the earth" - Vox

Um dos inventores da pílula esclarece o que disse

Carl Djerassi, um dos inventores da pílula, esclarece o que disse: Response: I never blamed the pill for the fall in family size Comment is free The Guardian: "I never blamed the pill for the fall in family size. It's not about birth control; people make choices for personal and economic reasons. "

Como se envelhece na Europa (de modo diferente, conforme os países)

Grow Old In Good Health: Vast Disparity Between European Countries

ScienceDaily (2008-11-26) -- Although life expectancy is constantly growing in the countries of the EU, living longer isn't always the same as living well, and knowing to what age someone will live in good health remains a different question altogether. ... > read full article

Crise alimentar a nível mundial

Tenho aqui um conjunto de artigos sobre a crise alimentar a nível mundial. O problema tem causas próximas (uma é retratada no gráfico acima - ver em Econbrowser: Food prices ) e outras, que o não são tanto, já que se prendem com o enquadramento político, e a evolução económica tecnológica, do sector agrícola nos últimos 15 a 20 anos. Uma questão que se coloca é a rapidez com que esta crise será resolvida e o que terá de ser tido em linha de conta na transformação da actividade nos próximos anos - e.g., subsidiação da agricultura, comércio internacional de produtos alimentares, produtos agrícolas geneticamente modificados... Isto tudo servindo de alerta à necessidade de se estar atento às consequências das alterações climáticas na actividade agrícola - por exemplo, uma das modificações previstas como decorrendo daquelas será o aumento, em quantidade e em intensidade, dos surtos de seca...

• Econbrowser: Food prices: Comentário à política de subsidiação da produção de etanol a partir do milho:

  "As a result of ethanol subsidies and mandates, the dollar value of what we ourselves throw away in order to produce fuel in this fashion could be 50% greater than the value of the fuel itself. In other words, we could have more food for the Haitians, more fuel for us, and still have something left over for your other favorite cause, if we were simply to use our existing resources more wisely. We have adopted this policy not because we want to drive our cars, but because our elected officials perceive a greater reward from generating a windfall for American farmers. But the food price increases are now biting ordinary Americans as well."

• Geoorge Monbiot: Credit crunch? The real crisis is global hunger. And if you care, eat less meat Comment is free The Guardian:

  "Never mind the economic crisis. Focus for a moment on a more urgent threat: the great food recession that is sweeping the world faster than the credit crunch. You have probably seen the figures by now: the price of rice has risen by three-quarters over the past year, that of wheat by 130%. There are food crises in 37 countries. One hundred million people, according to the World Bank, could be pushed into deeper poverty by the high prices. But I bet that you have missed the most telling statistic. At 2.1bn tonnes, the global grain harvest broke all records last year - it beat the previous year's by almost 5%. The crisis, in other words, has begun before world food supplies are hit by climate change. If hunger can strike now, what will happen if harvests decline? There is plenty of food. It is just not reaching human stomachs. Of the 2.13bn tonnes likely to be consumed this year, only 1.01bn, according to the United Nation's Food and Agriculture Organisation, will feed people."

• FT.com / Comment & analysis / FT Columnists - A modest proposal for preventing world famine:

  "...Manila has not been able to buy enough rice abroad to secure food for its people, because no one has wanted to sell. ...The price of rice has more than doubled in a year. ... Riots over food prices have erupted across Africa .... It is tempting to assume that the problem is purely one of supply and can be fixed by genetically modified plants or investment in a new “green revolution” to boost crop yields.

  The three most productive solutions, however, are all matters of policy.

  First, there is an urgent need for a sustained liberalisation of agricultural trade. The immediate cause of this crisis is not – perhaps surprisingly – a shortage of food. The problem is the sudden reluctance of traditional exporters to sell their surpluses. ... Trust in the efficiency and liquidity of the market has collapsed. Farm protectionism is not new and international markets are grotesquely distorted by tariffs and subsidies. The main producers – particularly the European Union and the US – have jealously protected their farm sectors from foreign competition, partly on food security grounds. International farm trade has nevertheless managed satisfactorily for decades to redistribute surpluses of staple foods. The current seizures in the markets are therefore a cause for general alarm. ...

  The second level at which policies need to change is national. Like international trade, domestic trade in farm produce is often highly distorted. While developed nations tend to support their farmers at the expense of consumers, developing countries typically subsidise city-dwellers at the expense of rural smallholders, who receive low prices and have no incentive to increase their output.

  Third and last, governments need to examine their population policies and limit population growth. Although there is enough grain to go round at the moment, you do not need to be a neo-Malthusian to worry about the demand implications of a global population rising by about 80m people a year or to notice that countries with fast-growing populations... are especially vulnerable to disruptions in the world’s food trade. Perhaps we should not worry too much that global rice stocks are expected to fall this year to the lowest level in 25 years. Some of the changes recommended above for international and domestic food trade regimes could reverse the decline, probably within a few years.

  A more disturbing thought is that we may in the longer term be approaching the limits of our ability to exploit the natural resources required for food production – crude oil, cultivable land, soil fertility and available fresh water, to name a few. Strains on one resource, furthermore, quickly lead to additional strains on another. To make fresh water, more cities are burning fuel to desalinate seawater, but that helps push up the price of oil. To make substitutes for crude oil, farmers are being encouraged to switch to biofuel production, but that uses almost as much fuel as it produces and contributes in its turn to shortages of food."

• Crop Prospects and Food Situation, No.2,April 2008 Across Globe, Empty Bellies Bring Rising Anger - New York Times.

• A Drought in Australia, a Global Shortage of Rice - New York Times:
  "The collapse of Australia’s rice production is one of several factors contributing to a doubling of rice prices in the last three months — increases that have led the world’s largest exporters to restrict exports severely, spurred panicked hoarding in Hong Kong and the Philippines, and set off violent protests in countries including Cameroon, Egypt, Ethiopia, Haiti, Indonesia, Italy, Ivory Coast, Mauritania, the Philippines, Thailand, Uzbekistan and Yemen."

• Food The silent tsunami Economist.com:

  "Agriculture is now in limbo. The world of cheap food has gone. With luck and good policy, there will be a new equilibrium. The transition from one to the other is proving more costly and painful than anyone had expected. But the change is desirable, and governments should be seeking to ease the pain of transition, not to stop the process itself."

• Food and the poor The new face of hunger Economist.com:

  "But the food scare of 2008, severe as it is, is only a symptom of a broader problem. The surge in food prices has ended 30 years in which food was cheap, farming was subsidised in rich countries and international food markets were wildly distorted. Eventually, no doubt, farmers will respond to higher prices by growing more and a new equilibrium will be established. If all goes well, food will be affordable again without the subsidies, dumping and distortions of the earlier period. But at the moment, agriculture has been caught in limbo. The era of cheap food is over. The transition to a new equilibrium is proving costlier, more prolonged and much more painful than anyone had expected."

Aditamento (08.04.21)

A-propósito ver também Les biocarburants sont-ils coupables ? Telos.

Malthus revisitado

Afinal, será que a história acabará por dar razão a Malthus? É conhecida a tese de Malthus do crescimento da população tender, historicamente, a ultrapassar o crescimento dos bens alimentares, dando lugar a alterações que corrigem, de modo drástico esse desiquilíbrio - guerras, fomes, epidemias. Segundo alguns, Malthus limitou-se a constatar características que tinham definido o comportamento demográfico das sociedades humanas até então, não tendo feito previsões para o futuro. Se não as fez, outros fizeram-no, no preciso momento que eclodia a Revolução Industrial, que tornou essa previsão numa das mais espectacularmente erradas de sempre. Armados dessa lição os economistas têm-se mostrado sempre cépticos às teses neo-malthusianos que tem aparecido, de vez em quando, e esse cepticismo tem mostrado bom fundamento - face à escassez de um dado recurso (medida pelo aumento do seu preço no seu mercado) a economia tem sido levada (incentivada) a descobrir alternativas, assentes, nomeadamente, na investigação científica.

No entanto, mais recentemente, devido a diversos factores - o crescimento das economias emergentes; os receios da ocorrência do pico de produção do petróleo e o recurso aos bio-combustíveis... - traduzidos numa procura em crescendo de todo o tipo de recursos - alimentares, minerais, etc. - reavivaram-se os receios de se estar face à iminência de cenários malthusianos à escala planetária. A rapidez e a intensidade dos efeitos que induziriam o aparecimento desses cenários impossibilitariam o funcionamento, em tempo, daquele outro mecanismo de ajustamento (o assegurado pelos mercados) - facto esse, agravado pelo facto do preço formado no mercado, de um dado recurso, em muitos casos, não medir, não reflectir, de modo adequado o seu nível de escassez efectivo. Acresce a tudo isto, a possibilidade destas evoluções acarretarem mudanças de fase ("tipping points") dando lugar a cenários de não retorno à normalidade que conhecemos. Naturalmente, as evoluções determinando a possibilidade de um mundo malthusiano, são aquelas que reforçam o aquecimento global.

As ligações desta nota apontam para artigos e apontamentos sobre esta questão. Este New limits to Growth Revive Malthusian Fears, no Wall Street Journal, é muito interessante e completo (a figura acima foi retirada dele). O seguinte Carnegie Mellon Economist Says Oil Prices Aren't High Enough refere a posição de um economista que defende estar o preço do petróleo ainda baixo (nos EUA) e, finalmente, um apontamento do blogue Free Exchange do The Economist, The return of Malthus, discute os aspectos económicos desta questão.

Crítica de livros

Críticas de livros, quase todas do Book Review, do New York Times. Por vezes, um conjunto de livros ressaltam - e bem gostaria de os ter todos (faz falta orçamento e, uma boa livraria de livros ingleses e americanos, em Lisboa, ajudaria - na Amazon, só FC). À falta dos livros, lê-se as críticas, o que apesar de tudo, não é mau.

• Human Smoke - The Beginnings of World War II, the End of Civilization, de Nicholson Baker, é um livro interessante, cheio de pormenores históricos inusitados (vejam à frente, alguns exemplos) mas é controverso (errado) na afirmação da sua tese principal: do erro que teria sido travar a Segunda Grande Guerra - a este propósito ver Richard Cohen - Yes, It Was a Good War - washingtonpost.com.

  A crítica refere, nomeadamente, a atenção ao detalhe por parte do autor, de que resulta o relevar de factos e de frases - alguns e algumas, muito politicamente incorrectos (agora, não na altura) - de políticos que aprendemos a respeitar (e que continuaremos a respeitar), mas esclarecedores das perspectivas e contradições à altura existentes e que a história (alguma história) tende a esquecer.

  Um exemplo: "But sometimes it is the simple stark fact that makes you sit up straight for a moment, like this one from early in the book: “The Royal Air Force dropped more than 150 tons of bombs on India. It was 1925.” This, coming soon after an account of the proposed bombing of civilian targets in Iraq in 1920 (with Churchill writing: “I am strongly in favor of using poisoned gas against uncivilized tribes”), sets a theme for the book, which Baker will skillfully weave into the fabric of events mainly between 1920 and 1942 — that the bombing of villages and cities from the air represents “the end of civilization.”
  

• Fatal Misconception - The Struggle to Control World Population, de Matthew Connelly: a crítica feita a este livro é, em si mesma, muito informativa. Aponta para os principais momentos de um processo que conta já com uma história de um século e para todos os desvios que foram cometidos em nome de um problema real, mas respeitando apriorismos ideológicos maus: sexismo, racismo, eugenismo...
  

Estimativas da população mundial

Qual é o tamanho expectável da população humana, por volta de 2050? Qual é a sua efectiva medida hoje? Esta nota Earth 2050: Population Unknowable? do Dot Earth, New York Times Blog, discute a qualidade das respostas estatísticas dadas. De qualquer forma, fala-se 9 mil milhões em 2050 contra os 6,7 mil milhões (estimados) de hoje [+ 34,3%] - em 1830 teria havido 1 mil milhões de humanos. Ver gráfico acima.

Aborto, gravidez indesejada e planeamento familiar

George Monbiot, no Comment is free, no The Guardian, Our awful rate of abortion is partly the Cardinal's responsibility, fala-nos do aborto e das responsabilidades em presença: uma citação, interessante, a diversos títulos: "Murphy-O'Connor [cardeal] has denounced contraception and abortion many times. That's what he is there for: the primary purpose of most religions is to control women. But while we may disagree with his position, we seldom question either its consistency or its results. It's time we started. The most effective means of preventing the deaths of unborn children is to promote contraception."

Convém ler o artigo, por todos os motivos: tem, nomeadamente, estatísticas muito interessantes, mas não só. Vejam este excerto (tem aplicação regional):

"There is also a clear relationship between sex education and falling rates of unintended pregnancy. A report by the United Nations agency Unicef notes that in the Netherlands, which has the world's lowest abortion rate, a sharp reduction in unwanted teenage pregnancies was caused by "the combination of a relatively inclusive society with more open attitudes towards sex and sex education, including contraception". By contrast, in the US and UK, which have the developed world's highest teenage pregnancy rates, "contraceptive advice and services may be formally available, but in a 'closed' atmosphere of embarrassment and secrecy".

Poderia apresentar ainda excertos muito duros deste artigo - fica ao vosso critério, acedê-lo ou não. No entretanto, e a-propósito, confesso a minha surpresa, em relação à notícia, dada nas notícias da RTP Açores, quanto à incidência da gravidez na adolescência nos Açores e o facto da sua dimensão não se ter alterado nas últimas décadas. Algumas das razões para isso entroncam naquilo que é dito no artigo de Monbiot - outras, não! A falar depois...

EUA: projecções demográficas para 2050

O NYT refere as conclusões das projecções demográficas, feitas por um estudo da Pew Research Center, para os EUA, em 2050. Rácio de dependência (2050): 72%; Imigrantes trabalhadores (2050): 23%; Hispânicos trabalhadores (2050): 31%; Estrangeiros (2050): 19% etc.. É de manter como referência. Ver aqui: Study Foresees the Fall of an Immigration Record That Has Lasted a Century - New York Times. Um excerto: "What such an outcome could portend, other analysts have said, is a nation riven politically between older, whiter, voting retirees who are increasingly supported by a younger, darker, working population that, as immigrants, may be disproportionately ineligible to vote."

Ilha de Páscoa: colapso - uma lição para os nossos dias

Physorg.com dá conta da construção de um modelo matemático (simples) aplicado à explicação do colapso da sociedade da Ilha de Páscoa, depois da colonização polinésica e a chegada dos primeiros europeus. Todas as civilizações dependeriam da "capacidade de carga" (carrying capacity) do ecosistema onde estão localizadas, com a sua população a dever oscilar entre um mínimo que permita a sua viabilidade e um máximo coincidente com o nível de equilíbrio que assegure a reprodução indefinida da sociedade em causa. Isso é particularmente evidente para ecosistemas fechados - caso das ilhas. Alcançado um dado nível de população (e logo de recursos e de ritmo de produtividade na sua utilização) todos os ecosistemas (por maiores que sejam) são ilhas. É o caso do planeta Terra. As implicações são imediatas. A notícia pode ser lida aqui: Model of Easter Island Collapse Might Reveal Message for Today.

Ligações recomendadas: ciência

• Marie Smith, a última falante da língua Eyak, morreu com 89 anos - é um obituário belo, digno e suavemente triste (The Economist).
• A auto-evolução humana: promessas e riscos (The Economist).
• Pelo que respeita à genética, as últimas asseguram a nossa grande parecença (The Economist).
• Relação entre parentesco e fertilidade: outra explicação da transição demográfica para taxas mais baixas de fertilidade (The Economist)