My
latest Mind and Matter column for the Wall Street Journal:
Part of the preamble to Agenda 21, the action plan that came out
of the Rio Earth Summit of 1992, reads:
“We are confronted with a perpetuation of disparities between and
within nations, a worsening of poverty, hunger, ill health and
illiteracy, and the continuing deterioration of the ecosystems on
which we depend for our well-being.”
In the 20 years since, something embarrassing has happened:
a sharp decrease in poverty, hunger, ill health and illiteracy
and a marked reduction in
these global disparities. The conference that begins next week
in Rio de Janeiro, on the 20th anniversary of the first Earth
Summit, will nonetheless remain resolutely pessimistic about the
planet’s ecosystems and their capacity to support human beings
indefinitely if economic growth continues. The reasoning has
changed over time, however.
[For example, from here:
Although world population has increased by about 80% over this time
(World Bank 2009), the number of people below the $1 a day poverty
line has shrunk by nearly 64%, from 967 million in 1970 to 350
million in 2006. As for inequality, see chart above.]
The original claim, based on the influential 1972 best seller
“The Limits to Growth,” by the Club of Rome, was that resources
would have begun to run out by now. Instead supplies of minerals
have increased, thanks to ingenuity, technology and demand.
Later the emphasis shifted to humankind’s “ecological
footprint,” which, it was claimed, was exceeding the planet’s
carrying capacity. But this, too, took a blow when the most
thorough assessment of the world’s ecology, by Helmut Haberl of the
University of Klagenfurt in Austria,
found that people and their domestic animals were eating or
damaging just 23.8% of the vegetation growing on land, and that in
richer parts of the world they were enhancing the productivity of
the remaining vegetation by almost as much through irrigation and
fertilizer.
The Riocrats now have a new tack, which will dominate next
week’s discussion: planetary boundaries. An influential
paper in 2009 written by Johan Rockstrom of Stockholm
University and 28 colleagues argued that there are nine thresholds,
crossing any of which will trigger collapse of the Earth’s life
support systems: land-use change, loss of biodiversity, nitrogen
and phosphorus levels, water use, ocean acidification, climate
change, ozone depletion, aerosol loading and chemical
pollution.
The trouble with this approach, according to
a new report by Linus Blomqvist, Ted Nordhaus and Michael
Shellenberger of the Breakthrough Institute in San Francisco, is
that, for six of these measures, “there are no global tipping
points beyond which these ecological processes will begin to
function in fundamentally different ways. Hence the setting of
boundaries for these mechanisms is an arbitrary exercise.”
A good example is land-use change. The Rockstrom paper suggested
that if human beings convert 15% of the land surface of the Earth
to cropland, the world will pass a tipping point, because as
marginal land gets exhausted, a small increment in food demand
would produce an accelerating increase in cultivation. Currently we
cultivate about 11.7% of the land. Yet there is no evidence that
anything special happens at 15%. In the
words of Steve Bass of the International Institute for
Environment and Development in London, “If anything, the opposite
has probably been more true: Converting land for farming and for
industry has clearly delivered a great deal of well-being.”
Furthermore, the use of synthetic fertilizer has kept that
percentage lower than it would otherwise have been. The independent
scholar Indur Goklany
argues that, “had global agricultural productivity been frozen
at its 1961 level, then the world would have needed over 3,435
million hectares (Mha) of cropland rather than 1,541 Mha actually
used to produce as much food as it did in 2002.” That saved an area
about as large as is set aside for conservation.
The “boundaries” approach needs to incorporate the possibility
that, thanks to technology, fossil fuels and minerals, people are
already living more lightly on the land than we did in the
past.