Human land use practices alter ecosystem energy flows to a significant degree. This work
uses the “Human Appropriation of Net Primary production” (HANPP) as an aggregate measure
to quantify this human dominance over nature. The system under investigation are the
Philippines on national level, the timeframe is set from 1910 to 2003. This study provides the
first long term time series of HANPP for a tropical developing country with a colonial history.
Available statistical data and simple model assumptions are used to generate a continuous
assessment of HANPP and its subcomponents which include human biomass harvest. This
makes it possible to trace fundamental changes in human land use practices, in socioeconomic
biomass metabolism and in agricultural productivity.
The results show a two-fold increase in HANPP over the period observed. The human population
of the Philippines increased 10-fold within the same timespan. Drastic changes in human
biomass use had to occur to maintain biomass supply for basic human needs, such as food,
feed, and fuel. Over the last decades HANPP was continuously high; significantly over 50%.
Less than half of the potential ecosystem productivity remained in the system to be used by
other organisms. The observed changes in societal biomass metabolism include an aerial expansion
of permanent agriculture in a first phase and the shift to “modernized” intensified
agriculture in a second phase. While the first phase was related to strong increases in HANPP,
the second phase, which started in the 1960s with the so-called “Green Revolution”, was characterized
by increased biomass harvest through rising per area yields. The latter process contributed
to a stabilization of HANPP, which was achieved through high external, fossil fuel
depended inputs and linked to environmental costs, such as eutrophication and contamination
through pesticides. Other developments that illustrate high human pressure on nature include
the overexploitation of forest resources, which led to a peak in wood production in the early
1970s and a drastic decline since then; migration flows from regions with deteriorated or
overused natural resources; the change to a negative physical biomass trade balance in the
1980s. Consequently, the results of the presented research suggest that the nation might be at
its biophysical limits in relation to a number of aspects.