turies. Unfortunately, the comparison 
is totally without basis in fact. The 
current estimate of many Brazilian of- 
ficials, for example, is that with cur- 
rently available technology, only ap- 
proximately 0.3 percent of the vast 
lowland forests in the Amazon Basin 
can be put into sustainable agricul- 
ture; about 95 percent of all the land 
in Brazil that is capable of sustained 
agricultural productivity is already un- 
der cultivation. The country now has 
some 90 million people, of which about 
a third are malnourished. Since the 
population is expected to double dur- 
ing the next twenty-three years, how 
malnutrition could be held even at 
the same proportionate level as it is 
today is unclear. Indeed, if the plans 
of the Brazilian government to alle- 
viate the nation’s acute energy short- 
age by planting sugar cane for the 
production of alcohol are imple- 
mented, approximately one-sixth of 
the currently productive agricultural 
land of Brazil could be taken out of 
production, a sacrifice that surely can- 
not be sustained in a country where 
a very large number of people are 
malnourished. 
One of the most unsuitable purposes 
for which the tropical forests are being 
cut down is beef production. The kinds 
of cattle ranches that have been de- 
veloped with such enthusiasm 
throughout Latin America during the 
past twenty years have proved eco- 
logically unstable. The fertility of the 
ranch soils declines over a period of 
ten to twenty years until profitable 
cattle production is no longer possible. 
For most tropical soils, fertilizer — 
even when funds can be found to pur- 
chase it — does not restore fertility. 
Under the influence of the beating 
tropical sun and high precipitation, 
the structure of many tropical soils 
simply disintegrates, rendering them 
unable to retain nutrients. A number 
of tropical soils harden into cementlike 
layers, called laterites, that are im- 
pervious to the plow and essentially 
useless for agricultural purposes. Only 
much greater attention to understand- 
ing how undisturbed tropical ecologi- 
cal system^ function and — through ex- 
perimental manipulation of these 
systems — to finding ecologically suit- 
able productive agricultural systems 
will succeed in alleviating such prob- 
lems. Intercropping, for example, 
which involves the growing of several 
different kinds of crops together, will 
probably prove to be more stable in 
the tropics. 
Regardless of whether they are de- 
veloped wisely or unwisely, tropical 
forests are being cut down, and if their 
destruction and conversion is indeed 
irreversible, approximately one million 
kinds of plants and animals, or one- 
quarter of all that exist, will become 
extinct during the next thirty years, 
and possibly another million during 
the course of the twenty-first century. 
Such a rate of extinction is postulated 
on the destruction of the natural com- 
munities in which these plants and 
animals occur and also on the inability 
of many of these organisms to repro- 
duce outside undisturbed tropical for- 
est. The loss of biological diversity in 
the tropics as a result of these extinc- 
tions will have serious consequences 
for the human race. Every species is 
genetically unique. We cannot study 
an extinct species, we cannot use it, 
and we cannot develop it into some- 
thing more useful. 
Current conservation efforts, unfor- 
tunately, still tend to concentrate on 
a few obvious or well-known plants 
and animals, such as the Furbish louse- 
wort, the snail darter, the elephant, 
or the tiger, while tens of thousands 
of other species go extinct without 
fanfare. Probably twenty times as 
much is spent annually to try to pre- 
serve the roughly thirty surviving Cali- 
fornia condors as is spent to find new 
kinds of tropical plants that might be 
important sources of food, fuel, or 
medicine. We must ask ourselves 
which kind of action has the greatest 
potential for alleviating human misery 
and helping to create a stable world. 
By the end of this century, three- 
fifths of the world’s population will 
be living in the tropics, and one-fifth 
in China. The remaining fifth will in- 
clude all those people in the United 
States, Canada, Europe, the Soviet 
Union, Japan, Australia, New Zea- 
land, temperate southern Africa, and 
temperate South America. The pro- 
portion of people living in the tropics 
will become progressively higher dur- 
ing the course of the twenty-first cen- 
tury. The projected picture for the 
world’s tropical regions is by no means 
a promising one: current technology 
has not found a way to bring into 
cultivation more than 5 percent ad- 
ditional arable land in the tropics; the 
world’s fisheries are badly depleted 
and declining; the roughly 400 million 
people who now make a living by clear- 
ing and farming small plots in tropical 
forests will have doubled in number 
and be essentially without any place 
to turn by the end of the present cen- 
tury; there is no obvious source for 
energy in most tropical countries other 
than burning up their forests, displac- 
ing productive agricultural systems 
with energy-producing crops, or de- 
veloping their nuclear capabilities; 
and the total excess food productivity 
possible in temperate regions will be 
patently unable to feed the roughly 
125 million people that will be added 
to the populations of tropical countries 
each year during the first part of the 
twenty-first century. 
What happens in the tropics affects 
the entire world. For example, the 
shortages of many kinds of commod- 
ities, which developed countries for- 
merly obtained from the tropics at 
very low prices, are already contrib- 
uting to worldwide inflation and hence 
instability, and they will do so to a 
greater extent in the future. As a mat- 
ter of self-interest and national secu- 
rity, all temperate, developed coun- 
tries ought to begin to contribute 
substantially to the development of 
sustainable productive agricultural 
and forestry systems in the tropics. 
We in the United States must ade- 
quately fund appropriate programs to 
learn more about tropical ecosystems 
and about how to use this knowledge 
for human benefit as directly as pos- 
sible. To do this, we must take steps 
to increase the number of scientists 
competent to deal with such problems, 
both in the United States and in the 
countries directly concerned. Legal 
authority to conduct programs over- 
seas must be granted to branches of 
government, such as the Department 
of the Interior, that can make a strong 
contribution in this area. Agencies 
such as the National Science Foun- 
dation and intergovernmental efforts 
such as the United Nations Man and 
the Biosphere Program, which have 
proved their ability to conduct studies 
in environmental biology, must be 
granted greatly increased funds for 
tropical research. In its foreign-aid 
programs, the United States must pay 
more attention to the importance of 
building up the research capabilities 
of the tropical countries themselves. 
The countries of the world, devel- 
oped and undeveloped, can prosper 
and exist in peace only in a relatively 
stable world. If we are to enjoy the 
benefits of global stability during the 
next century, indeed if we are to sur- 
vive, we must seize the opportunities 
that are still available to us but which 
are diminishing every day. □ 
32 
