Each spring, I give a favorite lecture, an homage to a Belgian mathematician, Pierre François Verhulst.
In two publications (1838 and 1847), Verhulst argued that the growth rate of a population (N = numbers or density) can be described as dN/dt = rN(1-N/K).
This, as I love pointing out, is as elegant a model as one can find in applied mathematics because it is simple, and the two constants have biological interpretations. K is carrying capacity; r is the population’s intrinsic growth rate. If you interpret the interaction of N and K as the joint dependence of the Ns on K and recognize that species can interact because of a joint dependence on K in the same way that individuals can, you realize that nearly the whole of the science of ecology turns on this singular little equation which says that nothing grows without limits (the little equation is the starting point for more sophisticated models). Ecology is the science of understanding limits to growth.
Verhulst and his followers were drawn into intense arguments about whether his equation was a “law” of population growth analogous to the laws of physics or chemistry. I am in the “not a law” camp (I have an arcane concern about how to think about stochasticity) but were I forced to choose one exception; it would be Verhulst’s law of density dependent growth – known today as logistic growth.
I am, of course, reflecting on the recent discussions of ecology and economics in the Reformed Journal and its blog (hat-tips to Professors Rienstra, Smith, Steen, and Zylstra).
The lesson from my discipline, that nothing grows without limits, has two important corollaries 1) joint dependencies tie the interests of individuals and species together and 2) limits to growth are enforced by negative feedbacks.
To amplify a point Professor Zylstra made, the economy, in its conventional sense of trade in goods and services for people, does not exist in a vacuum. More than simply being connected to…or associated with …the goods-and-services economy is embedded in a larger real economy of atmospheric carbon cycling, soil nutrient cycling, photosynthesis, hydrology, ecosystem dynamics, and other nature systems.
Hence when Professors Steen and Smith write that “economic growth is nonetheless a moral imperative because, arising from human work, agency, and creativity, it provides the resources for improved material wellbeing,” their assertion is incomplete.
Economic growth (and therefore, human wellbeing) is also a draw on the world’s limited resources, its limited capacity for regeneration of those resources that we conventionally consider to be renewable and, most critically, the earth’s limited capacity to absorb the wastes that economic growth must, by necessity, create. In this sense, Professor Rienstra is correct when she writes that perpetual growth is physically impossible.
This point is critical because we collectively are already well beyond the planetary limits for sustainable growth. Therefore, the larger moral imperative is to prevent further damage because the stakes are so high. I could finish this essay simply listing the negative feedbacks we are experiencing, most of which fall most severely on the poor and the non-human parts of creation.
Climate scientists tell us that we are on track to make large parts of the globe unlivable within the lifetimes of some of the people who will read this, not to mention the lasting damage done to non-human creation. Growth requires consuming and polluting at some level and we have consumed and polluted ourselves into a planetary crisis and searing injustice.
Should we seek flourishing for the poor of this world? With all urgency! But the energy and resources to support that flourishing should come from the consumer gluttony of wealthy people/countries so that green house gas emissions stop increasing.
I’ll pause here to acknowledge that Professors Smith and Steen wrote to defend their discipline from a perceived unfair criticism. Their point was that “(e)conomists as a whole focus on the tradeoffs between different choices that people and nations make, as well as the full costs of such decisions. Politicians and policymakers, businesspeople and individuals, essayists and other analysts often ignore both costs and benefits, while economists delight in making them clear. Insisting on thinking about tradeoffs is one of the most crucial contributions economics makes to social science research.” (Note that Professor Steen commented on Professor Zylstra’s post on Tuesday to reassert that economists do, in fact, count environmental costs. It’s worth a read.)
Fair enough. I would join Professors Steen and Smith in defending academic economists for the important work they do, although I am dubious too (with the others) about their claim to be broadly “counting the full costs of those decisions” and “making them clear.”
I rarely see environmental costs, especially cumulative costs evaluated with the gravity they require. Failure to count and show the cumulative environmental costs makes trade-offs less clear with an asymmetry that favors economic activities that incur further damage.
I know that academic economists are not a monolith, that there are those who are rightly skeptical about unlimited growth. There are economists focused on environmental sustainability and mitigation of the damage done. Some of them are key contributors to the IPCC process. Some are friends of mine.
But blaming “Politicians and policymakers, businesspeople and individuals, essayists and other analysts” for ignoring both costs and benefits seems like a bit of a reach and it’s probably a driver for the pushback Professors Steen and Smith got from Professors Rienstra, Zylstra, (and Bouma-Prediger in the comments on Professor Zylstra’s post).
I know from experience, including experience here, that for any environmental problem there is always a voice arguing that earthkeeping is too expensive and all too often arguing their point under the color of “economic” wisdom. Consider that voice as separate from academic economists like Professors Steen and Smith if you will, but that voice has been piping up for decades and is well known. Aldo Leopold called them “economic moralists” in his lament for the extinct passenger pigeon (also “economic determinists,” Sand County Almanac 1948) and his famous argument for a land ethic begins with an admonition to “quit thinking about decent land-use as solely an economic problem.”
Economic moralists love the colorless term “externalities” because they can hide environmental costs there – especially if they are hard to measure in dollars and cents. The outsize influence of the economic moralists is easy to comprehend. They give cover to interests that privilege near-term gains for shareholders and CEOs over the interests of poor people and non-human creation. They’re the reason this New Yorker cartoon has such resonance.
At a minimum, Professors Steen and Smith’s noble discipline (I am sincere here) has a problem in how it is translated and used. From my vantage here in the earthkeeper cheap seats, the climate crisis itself is the cumulative looming feedback from economic moralists relentlessly winning policy arguments for more growth by ignoring or discounting environmental costs.
We’ve known about the problem of green house gas emissions for decades. Exxon’s scientists knew in the 1970s. Kicking the can down the road was an economic decision and even as recently as this week Reuters is reporting that despite most big fossil fuel companies pledging to achieve net-0 emissions, none (!) of them had plans in place to achieve those plans. It’s the standard green-washing BS we’ve come to expect from fossil fuel companies, but you can bet that the decision to dupe their customers stems from an economic calculation that it’s better for their bottom line.
Similarly, the “economic” content in our popular media is mostly about stroking the machinery of capitalism to create and hoard wealth and breathless tracking of impossibly precise increments of stock market indicators in real time. What of the economic realities of climate justice? It’s indicators? Why not maintain a focus on the most urgent work of humanity right now?
It doesn’t sell. Pity that.
