Introduction:
Can our planet continue to support us despite increasing population growth?
The subject of population growth often elicits a neo-Malthusian pessimism
from the academic community about the future of the planet. The popular
argument persists that population growth will eventually result in such
a crowded world that the earth will no longer be able to sustain its human
population. However, more recently, economists have begun to challenge this
traditionalist view, the pessimistic perspective that a growing population
will lead to our species' demise. In light of this debate, my paper will
explore the effect that population growth has on the natural resources of
rural communities. I will focus specifically on the quality of agricultural
land, the number of forests and planted trees, and the quantity of land
used for livestock production in developing countries where the majority
of the world demographic changes are and will be happening. I will conclude
that, although population growth can certainly lead to the degradation of
land and other natural resources, this degradation is not inevitable. The
public policy of sustainability, the land management institutions, and the
implementation of better technologies can all minimize the effects of population
growth on natural resources.
This paper is organized as follows: I will first present a case study of
sub-Saharan Africa that illustrates the devastating effect that population
growth can potentially have on a region's natural resources. I will then
examine empirical evidence gathered from over 150 factual studies (Scherr
40) of how demographic change affects forests and planted trees, agricultural
land, and land used for livestock production, illustrating that the situation
in South Africa may be only one possible result of population growth, rather
than the rule. Then I will describe how microeconomic analysis explains
how population growth does not always result in population degradation.
Finally, I will finish with some policy suggestions for how natural resource
deterioration can be avoided.
Section 1: Sub-Saharan Africa
Despite the effects of AIDS, the population of sub-Saharan Africa is growing
faster than in any other region of the world. This rapid expansion has increased
the pressure on the land to produce for a larger population. Increasing
demand from the expanding population has pushed much of the land in sub-Saharan
Africa over its carrying capacity and resulted in significant soil nutrient
depletion because farmers are forced to condense fallow periods, limit soil
fertility regeneration, and increased the cultivation of less hospitable
land. Unfortunately, nutrient depletion of the soil is not being adequately
combated by natural and man-made inputs like fertilizing and terracing.
Resources like water, wood for fuel, or off-farm capital (manure, mineral
fertilizer) are either not available or are being poorly utilized, thus
preventing proper soil management that could meet the needs of an expanding
population.
Section 2: Examination of Empirical Evidence from Around the World
The situation in sub-Saharan Africa is not necessarily representative of
the situation around the world or even in other developing countries. The
empirical evidence gathered from numerous case studies of land management
and land use collected around the world reveals that population growth does
not necessarily threaten three main indicators of land quality: forests,
agricultural land, and the land used in livestock production (Templeton
and Scherr 903).
Most empirical evidence does indicate a strong statistical correlation between
population growth and deforestation (Scherr 40). According to multivariate
statistical analysis of data collected by the Food and Agriculture Organization
of the United Nations (FAO) from 98 countries with low and medium income
levels indicates that population growth of 1% between 1975 and 1985 did
lead to a decrease in forest cover of 0.12% between 1980 and 1985 (Templeton
and Scherr 905). From this data it would be easy to conclude that population
growth directly leads to deforestation. The potential explanation is easy
to understand: more people lead to a greater demand for wood, which then
causes deforestation. However, the causal link between the two variables
is in fact weak. Population growth does not always precede deforestation
and is not necessarily the culprit of forest loss (Templeton and Scherr
905). Data from the effects of expanding plantation agriculture in Malaysia
and ranching, logging, and plantation agriculture in Costa Rica illustrate
this point. Also, Population growth can actually induce tree planting. Planting
trees can help large local populations meet a variety of subsistence needs,
create market opportunities for fruits, wood products, resins, and fuel
as well as potentially controlling the erosion of soil and even fulfilling
other watershed functions of natural forests (Scherr 40).
It must be said that planted trees are not a perfect substitute for natural
forests. Although there are no studies assessing the environmental impact
of planted forests, predictably, there will be some loss of habitat for
some species and thereby a loss of biodiversity. However, there is little
doubt that tree planting does negate some of the more potentially disastrous
effects of natural resource depletion as a result of population growth.
Tree planting, primarily on plantations, is the reason why increases in
rural population densities in Asia do not statistically affect the total
rate of change in forests and woodland areas in Asia (Templeton and Scherr
905).
Population growth is also statistically linked to the increase in the amount
of land used for agriculture. Also, population growth is linked to the frequency
that land is used for agricultural production. When there is less land farmers
will use each plot more frequently and give it less time to regenerate.
As we saw in the case study of sub-Saharan Africa, expansion of arable land
and the increases in the frequency of which it is farmed can degrade a region's
natural resources. However, unlike what is happening in sub-Saharan Africa,
there are numerous case-studies from historical and more recent periods
that document how in longer settled areas, land-users respond to increases
in population size by investing in their land and making improvements that
conserve water, fertilizer, and other resources to allow for more frequent
cropping (Scherr 41). Many food producers begin using such techniques as
terracing, zero tilling, manuring, and composting to replenish soil (Tempelton
and Scherr 906). Studies have shown that population densities are positively
correlated with the aforementioned methods.
In addition, increased population will result in a larger, cheaper labor
force. Land producers can implement new production techniques that utilize
less land but compensate by using more labor when labor is cheap. In conclusion,
population growth does not necessarily adversely affect the availability
of usable land as long as food producers invest adequately to sustain it.
The third important aspect of resource utilization is the land used for
livestock production. In general, livestock populations tend to grow as
human populations grow from low to medium densities (Scherr 41). Increasing
livestock numbers do provide significant threat to natural resources. Expansion
of grazing lands can lead to increases in water, soil runoff and nutrient
depletion, as well as diminish biodiversity. However, this problem that
population growth causes in land use seems to be a self-correcting problem.
As population growth increses from medium to high levels the land used for
grazing begins to decrease. The increased competition for land leads food
producers to convert pasture land back into farm land and convert from land
intensive methods of feeding livestock to more labor intensive animal feeding
methods. Rather than letting animals graze, grass or forest fodder is collected
for animals in stalls. There is the possibility that excessively pruning
or felling trees for leaf fodder might contribute to the loss of forests;
however, this can be offset by planting fodder grass or shrubs in terraces,
gullies or other places where it is hard to grow anything else. This is
yet another example of how population growth does not necessarily have a
devastating effect on the quality of land.
Section 3: An Exploration the Determinants of Land Quality
It should now be clear that population growth often leads to more efficient
use of land and resources and in some cases actually improves the utilization
and efficiency of these resources. But why does this happen? It is important
to explore the determinants of land quality behind this empirical finding.
The first determinant lies in the microeconomic analysis that increases
in local population densities make land more expensive and labor cheaper
because of increases in land demand and labor supply (Templeton and Scherr
907). As the labor supply increases, producers gradually substitute labor
and capital intensive land improvements for larger portions of land itself
because the costs of using labor goes down while the competition for (and
as a result, the price of) land goes up. Increases in the value of land
relative to labor also induce land owners to invest in technologies and
to enhance their land's characteristics (or at least prevent their deterioration)
(Scherr 42). It is less expensive to invest in laborers who work at terracing
or other forms of sustainable landscaping designed to increase the productivity
and sustainability of land.
In practice, population growth will not result in the immediate improvement
of land productivity. Just as the pattern revealed by the above empirical
evidence pertaining to land used for livestock illustrates, there is an
initial decline in the productivity of land use in the early stages of population
growth. There is a lag because producers are slow to react to the change
in the relative of cost of labor to land. After they realize that the relative
value of their land has increased, land owners will move on to invest in
and protect their more valuable assets by hiring labor at relatively lower
costs. If one were to graph the relationship between land productivity and
population growth, with population growth on the X-axis and land productivity
on the Y-axis, he or she would observer a U-shaped relationship between
the two axes (Templeton and Scherr 907).
The desire for increased land productivity will also, as already stated,
create a market for more efficient technologies and methods. It will create
incentives for local invention and active borrowing of technologies better
suited to the new economic environment (Scherr 43). The result will be a
more efficient use of resources by the market as a whole.
Producers will also be influenced to invest in the productivity of their
land because of the effect that population will have on the product market.
Larger populations will inherently have a greater demand for food and goods,
and the price of goods will go up, thus offering further incentives for
landowners to believe that they will be able to profit on the improvements
that they make on their land. Also, with higher prices and higher profits,
producers will take in higher incomes, which they can invest into the more
efficient utilization of natural resources.
Finally, the decrease in land supply and the resulting rise in land value
induces the evolution of societal institutions. The desire to protect more
valuable land increases the benefits of creating and enforcing rules that
establish rights and obligations among people. The value of a system in
which rights are protected is that it increases the benefits and security
of engaging in collective action and investment. When property rights have
been established, people can potentially join together to buy land that
might not have been affordable to them on their own. Also, legal institutions
enable whole communities to invest a larger proportion of their collective
resources into potentially more resource rich plots while engaging in labor
sharing and other forms of collective work rather than all working separately.
The ultimate result is that there will be more investment in the land, which
will be able to sustain production at higher population levels.
Section 4: Policy Implications
We must ask: in light of the fact that continued population growth is inevitable,
at least until the middle of this century, what can be done to ensure that
we avoid the deterioration of our natural resources? There is certainly
no simple answer. The situation I described in the sub-Saharan Africa case
study illustrates that, although the consequence of population growth does
not have to be negative, it certainly can be. A policy designed to slow
the growth of population in these countries would be a good place to start.
There is no direct association with high rural populations and natural resource
degradation, however; "a slower or declining rate of population growth
would allow people more time to innovate and adopt products, technologies,
property rules, and collective management" (Scherr 44). People will
eventually innovate; however, without a policy to slow population growth,
it is unlikely that these changes in production techniques will happen before
much of the natural resources in these places are significantly depleted.
Our policies must aim at narrowing the gap between the private and social
interest in birth-rate reduction (Drechsel 257). Needless to say, the degradation
of our natural resources is a large problem and one that affects everyone.
It presents a daunting collective action problem. We must overcome people's
tendency to free ride and convince them to take action. Slowing population
growth is in everyone's interests.
At the same time, we also must continue to encourage policies designed to
support agricultural research and technological innovation. Land improvement
procedures should be designed with farmers and local institutions (both
communal organizations and NGO's) to meet their needs, using technologies
appropriate to local economic and social conditions (Scherr 45). Our policies
must work to develop rural communities as a whole and help to find location
specific market conditions that can be used to convince farmers of the economic
benefits of investing in their land (Drechsel 257).
Conclusion:
In conclusion, while it is clear that population growth potentially poses
a significant threat to the future of the planet and our food production,
rural livelihoods, and ecosystems, degradation of natural resources is not
inevitable. As the empirical evidence presented in this paper shows, population
growth can itself be a driving force in improving land management and increasing
investment in sustainable practices. This investment will not happen over
night, and there is a serious risk that current population growth rates
are too high for most communities to manage the challenge of adjusting to
rapidly changing demographics. It is up to us to adopt policies that give
local markets and institutions time to adjust to the added pressure that
population growth puts on natural resources. We can do this by minimizing
the initial negative impacts of population growth (illustrated by the U-Shaped
relationship between population growth and resource health described above)
through policies that support local efforts to slow population growth, increase
public awareness about the importance of resource sustainability, and by
supporting investment in technology and other innovative agriculture methods.
Policies like these can minimize the negative effects of population growth
on natural resources.
Scherr, Sara J. (1997), "People and Environment: What Is the Relationship between Exploitation of Natural Resources and Population Growth in the South?", Forum for Development Studies v0, n1 (1997): 33-58.
Templeton, Scott R.; Scherr, Sara J. (1999), "Effects of Demographic
and Related Microeconomic Change on Land Quality in Hills and Mountains
of Developing Countries", World Development v27, n6 (June 1999):
903-918.
Drechsel, Pay, et al. (2001), "Population Density, Soil Nutrient Depletion,
and Economic Growth in Sub-Saharan Africa", Ecological Economics
v38, n2 (August 2001): 251-258.