How large a human population can the earth sustain? Is
population growth essential for sustained economic prosperity? Last month, an
Ethical Musings' reader inquired whether the US has enough people to support
healthcare and other benefit programs for its aging population. Since then,
I've given those questions some thought. Here is the second installment (read the first here) of my
efforts to grapple with those issues; the third installment will appear in my
next Ethical Musings post.
First, the earth
has a limited carrying capacity, i.e., the earth can only sustain so many
living things (plants and animals of all types). Malthus had that much right. Improved
agricultural techniques, distribution of food and water, and other
technological advances have stretched and may further stretch earth's capacity,
but limits do exist because the earth consists of a finite set of resources.
Except for solar energy from the sun, we have no realistic way of importing any
material or resource from elsewhere in meaningful quantities nor are we likely
to develop such technology in the next one hundred years.
Second, most of
the available data confirms that humans are diminishing the earth's capacity to
sustain life. 2014 was the hottest year on record. A scientific study released
in January 2015 cites evidence showing that we have already crossed four of
nine planetary boundaries: deforestation, level of carbon dioxide in the
atmosphere, and the flow of nitrogen and phosphorous (both used in fertilizers)
into the ocean. (Will Steffen, Katherine Richardson, Johan Rockström, Sarah E.
Cornell, Ingo Fetzer, Elena M. Bennett R. Biggs, Stephen R. Carpenter, Wim de
Vries, Cynthia A. de Wit, Carl Folke, Dieter Gerten, Jens Heinke, Georgina M.
Mace, Linn M. Persson, Veerabhadran Ramanathan, B. Reyers, and Sverker Sörlin, "Planetary boundaries: Guiding human
development on a changing planet," Science, 1259855 Published online15 January 2015 [DOI:10.1126/science.1259855].)
James Lovelock's 2006 book, The Revenge
of Gaia, is a slightly dated but highly readable explanation of how humans
have diminished the earth's capacity to sustain life. A crisis point from which
there is now return is clearly approaching, though thankfully predictions that
we would have reached that crisis point by now have so far proven wrong, e.g.,
Malthus and the Club of Rome's 1972 report.
Third, current
models of economic prosperity incorrectly and unhelpfully presume constantly
increasing levels of consumption. Consumption drives production and production
generates wealth and income. Japan, the US, and other economically developed
nations face economic challenges because their stable or declining populations are
not increasing total consumption and thus appear unable to sustain their current
prosperity and to meet their financial commitments (pay government debt and
promised old age pensions, for example). Furthermore, contrary to accepted economic
theory, demand appears to diminish when prosperity passes some level (how many
candy bars, coats, condominiums, or consultants does any one individual really
desire?). People are now spending more time on mental pursuits (e.g., surfing
the internet) that spark less innovation, require less productivity, and
generate less consumption.
Fourth, less
developed nations in contrast to developed nations have huge unsatisfied demand
for economic goods and services. However, producing the good and services to
satisfy that demand inexorably places new requirements on earth's resources, as
the dense smog in China's major cities demonstrates. Even taking full advantage
of every possible technology and resource (including solar power), the earth
clearly seems unable to support all of its residents enjoying a Western
standard of living. Lovelock persuasively argues in The Revenge of Gaia that exceeding the earth's carrying capacity will
launch the planet into a self-destructive spiral from which recovery is
impossible.
Fifth, I do not
have a crystal ball with which to foretell the future. Indeed, the many
Christians who read the Bible to discover the future and God's timetable for the
events that they believe scripture predicts foolishly engage in eisegesis, i.e.,
knowingly misinterpreting scripture. Even if one accepts the Bible as the
source of revealed propositional truth (which I do not), Scripture repeatedly
emphasizes that no one knows God's timetable or plans. Similarly, I do not
claim to know if humans will exhaust earth's carrying capacity by 2050, 2100,
2500, or some later date. Yet, I know that the earth does have a finite
carrying capacity, that humans are rapidly depleting earth's finite resources,
and that our economic models and systems all rest upon the twin false premises
that both population and consumption can (and should!) grow without limit. Illustratively,
even if solar energy were to power ALL transportation, the amount of food that
people can grow on the earth has an upper limit. Sadly, the injunction to
multiply and fill the earth, found near the end of the biblical narrative about
Noah's ark, may be the only biblical injunction that humans can claim to have
obeyed enthusiastically and completely. In short, we need to make changes now,
while we may still have the opportunity to sufficiently alter course.
1 comment:
Another concern for carrying capacity of the Earth that is not fully appreciated is pointed out by Elisabeth Jeffries in her thought-provoking article in the current issue of Nature Climate Change 5, 93 (2015) entitled Coming Clean. "A shift to renewable energy will replace one non-renewable resource (fossil fuels) with another (metals and minerals)."
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