“Debate Malthusiano”

Ao longo de mais de 60 anos, a tendência do preço real das commodities foi de queda continua e significativa, a despeito de alguns choques notáveis (como o do preço do petróleo em 1973) – ver figura. E essa tendência tem lugar durante um período em que a população do mundo mais do que dobrou, passando de menos de 3 bilhões em 1947 para 7 bilhões em 2010.

Krugman (aqui) olha um pequeno intervalo de tempo e conclui:

 [T]oday, as in 2007-2008, the primary driving force behind rising commodity prices isn’t demand from the United States. It’s demand from China and other emerging economies. As more and more people in formerly poor nations are entering the global middle class, they’re beginning to drive cars and eat meat, placing growing pressure on world oil and food supplies. 

Krugman está contestando aqueles que vêem o aumento do preço das commodities como resultado da política monetária “frouxa”. Nesse ponto ele tem razão. Como mostra a figura abaixo, assim como o preço das commodities caiu na segunda metade de 2008 quando teve início a grande recessão – aqui medida pelo crescimento da produção industrial das economias emergentes – com a retomada dessas economias o preço das commodities voltou a subir . Como vimos na figura acima, o “efeito China” é relevante, mas isso implica que ajustamentos serão feitos ao longo do tempo…

Ao final, fico com Don Boudreau (aqui):

If economic growth since the industrial revolution coincided with increasing resource supplies, why should we expect that continued economic growth will suddenly start to have the opposite, dreary effects predicted by Mr. Krugman?”

Update: Esse artigo (aqui) é interessante:

As the leader of the Cornucopians, the optimists who believed there would always be abundant supplies of energy and other resources, Julian figured that betting was the best way to make his argument. Optimism, he found, didn’t make for cover stories and front-page headlines.

No matter how many cheery long-term statistics he produced, he couldn’t get as much attention as the gloomy Malthusians like Paul Ehrlich, the best-selling ecologist. Their forecasts of energy crises and resource shortages seemed not only newsier but also more intuitively correct. In a finite world with a growing population, wasn’t it logical to expect resources to become scarcer and more expensive?

Update (13/1): Guia definitivo do pensamento Malthusiano moderno. Muito divertdo (aqui):

This year the human population will reach seven billion. And probably the same number of newspaper column inches will be filled with Malthusian cant. We can expect everyone from unreconstructed population-controllers to trendy-sounding greens to fret out loud about the swarm of people now raiding Mother Nature’s allegedly sparse larder. Already National Geographic has kicked off a year of commentary on the seventh billion human by asking, ‘Can the planet take the strain?’. The New York Times says we could be facing our ‘Wile E Coyote moment’: ‘over the cliff but not realising it yet’.

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3 thoughts on ““Debate Malthusiano”

  1. Pingback: Commodity prices « Economics from Spain

  2. “If economic growth since the industrial revolution coincided with increasing resource supplies, why should we expect that continued economic growth will suddenly start to have the opposite, dreary effects predicted by Mr. Krugman?”

    Pergunta retorica, mas resposta bem simples: porque existem recursos finitos.

  3. Irineu
    Ninguém contesta que os recursos são finitos. Mas como vimos ao longo da história – Malthus há mais de 200 anos, o pessoal do Clube de Roma há mais de 40 anos – a “engenhosidade” humana contrabalança. A carta de Boudereau tem esse parágrafo:
    It’s not true that vigorous economic growth necessarily makes resources more scarce. In fact, history shows that, because of human ingenuity, the opposite is not only possible but prevalent.

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