via Mark Thoma, Jeffrey Sachs worries about transgressing our planet's boundaries

I'd really like to read the whole thing, but I don't have a subscription to Scientific American.  Maybe I'll buy a copy of the magazine at the airport tonight and read it on the way to DC.

Here's Thoma's snippet:

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.

The green revolution, in short, has not negated the dangerous side effects of a burgeoning human population, which are bound to increase as the population exceeds seven billion around 2012 and continues to grow as forecast toward nine billion by 2046. ...

It is not enough to produce more food; we must also simultaneously stabilize the global population and reduce the ecological consequences of food production—a triple challenge. A rapid voluntary reduction in fertility rates in the poor countries, brought about by more access to family planning, higher child survival and education for girls, could stabilize the population at around eight billion by 2050.

Payments to poor communities to resist deforestation could save species habitats. No-till farming and other methods can preserve soils and biodiversity. More efficient fertilizer use can reduce the transport of excessive nitrogen and phosphorus. Better irrigation and seed varieties can conserve water and reduce other ecological pressures. And a diet shifted away from eating beef would conserve ecosystems while improving human health.

Those changes will require a tremendous public-private effort that is yet to be mobilized. ... The window of opportunity to achieve sustainable development is closing.

Many in my business casually (and vehemently) dismiss this kind of talk as "MalTHusian," with heavy accent the "th" combined with an air of disgust.

This bothers me for a few reasons.  First, Malthus was brilliant and his simple and elegant model did a fantastic job of describing the history of the world up until the industrial revolution (see Delong on Clark, for example). It just isn't right to dis Malthus given his insights were so good and so important, at least historically speaking.

Second, today's dismal story is far different from Malthus.  Today's constraints are less about technology and an inability to control ourselves reproductively speaking.  Rather, today's constraints are political and institutional: poor governance and big-time externalities.  Population is one symptom of the problem, but it isn't the root source of the problem. And technological change, while rapid, may not be enough to compensate for poor governance and big-time externalites.  If, however, we can deal with root problems utopia is ours.  Problem is, that's a BIG if.


Thirdly, these problems are very real.  A billion people live in Malthusian-like misery, another couple billion are very close to it, so to be casually dismissive is as thoughtless as it callous.

Solutions will difficult to figure out and we need to be wary of unintended consequences of bad policies with good intentions. But we need to face these problems, squarely and seriously.