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OCR for page 5929
Proc. Natl. Acad. Sci. USA
Vol. 96, pp. 5929-5936, May 1999
Colloquium Paper
This paper was presented at the National Academy of Sciences colloquium "Plants and Population: Is There Time?"
held December 5-6, 1998, at the Arnold and Mabel Beckman Center in Irvine, CA.
World food trends and prospects to 2025
TIM DYSON*
Department of Social Policy, London School of Economics, London WC2A 2AE, United Kingdom
ABSTRACT This paper reviews food (especially cereal)
production trends and prospects for the world and its main
regions. Despite fears to the contrary, in recent years we have
seen continued progress toward better methods of feeding
humanity. Sub-Saharan Africa is the sole major exception.
Looking to the future, this paper argues that the continuation
of recent cereal yield trends should be sufficient to cope with
most of the demographically driven expansion of cereal de-
mand that will occur until the year 2025. However, because of
an increasing degree of mismatch between the expansion of
regional demand and the potential for supply, there will be a
major expansion of world cereal (and noncereal food) trade.
Other consequences for global agriculture arising from demo-
graphic growth include the need to use water much more
efficiently and an even greater dependence on nitrogen fer-
tilizers (e.g., South Asia). Farming everywhere will depend
more on information-intensive agricultural management pro-
cedures. Moreover, despite continued general progress, there
still will be a significant number of undernourished people in
2025. Signs of heightened harvest variability, especially in
North America, are of serious concern. Thus, although future
general food trends are likely to be positive, in some respects
we also could be entering a more volatile world.
The prospects for feeding humanity as we enter the 21st
century often are portrayed in a daunting light. For example,
we are told that the world's population has been growing faster
than cereal production since the early 1980s, and therefore that
global per-capita cereal output is falling now. The rate of
growth of world cereal yields also is said to be declining; the
strong implication is that this decline is caused by increasing
environmental production constraints. Victims of famine still
appear on television, and it is clear that there are many hungry
people in the world. In addition to these problems, between
now and the year 2025, the human population is expected to
rise from about 6 billion to 8 billion. So, especially in 1998, the
bicentenary of Malthus' Essay on the Principle of Population
(1), the issue symbolized by the Chinese characters above,
which together mean population (a person and an open
mouth), seems very apt.
With this as background and building on an earlier, much
more detailed analysis (2), this paper gives my broad-brush
assessment of world food prospects to the year 2025. Despite
the statements of the previous paragraph, I am cautiously
optimistic about our chances to better feed humanity in the
next few decades. Nevertheless, the importance and complex-
ity of the subject, the approximate nature of much of the data,
the need to simplify, and the inevitable element of uncertainty
when considering the future all should require no further
emphasis.
PNAS is available online at www.pnas.org.
Because of their central place in the human diet, cereals
will be my chief focus in what follows. Today, roughly half of
the world's cropland is devoted to growing cereals. If we
combine their direct intake (e.g., as cooked rice or bread)
with their indirect consumption, in the form of foods like
meat and milk (about 40% of all grain is currently fed to
livestock; ref. 3), then cereals account for approximately
two-thirds of all human calorie intake. I consider prospects
to the year 2025 mainly because world population projections
have a fairly reliable record over future time horizons of
about 30 years. My chief data sources are those of the United
Nations Population Division (4) and the Food and Agricul-
tural Organization (5, 6~.
This paper has three main parts. The first considers cereal
and food trends during recent decades, at both the world and
regional levels. The second uses demographic and cereal data
to sketch what I believe is a plausible broad scenario for the
future evolution of world cereal demand and supply. The final
part concludes with some brief comments about the context in
which the world's farmers must grow more food.
Cereal Production Trends
To consider the future we first must consider the past. Fig. 1
shows per-capita cereal production for the world as a whole
since 1951, when the entire human population numbered only
2.5 billion. The annual figures for per-capita output are
surprisingly variable and reflect volatility in the world's har-
vest. Nevertheless, it is clear from the 5-year moving-average
that world output generally has kept ahead of population
growth, despite the addition of some 3.5 billion extra mouths.
That said, there have been two periods of falling per-capita
cereal production. The first happened around 1960 and mainly
reflects the agricultural losses associated with Mao's disastrous
"Great Leap Forward" in China. The second period has been
since the early 1980s. The moving-average peaks at 371 kg in
1984 and has fallen to around 350 kg in the mid-199Os. Since
1984 the world's population has been growing faster than
cereal production. Note the hint that volatility in the global
harvest recently may have increased.
The fact that world population growth has been outpacing
cereal production since 1984 readily attracts attention, but
interpreted without any qualification, it is seriously misleading
for two reasons. First, it hides the fact that much of the recent
decline in world cereal production has occurred in relatively
well-fed regions. Second, it does not account for the fact that
the regional composition of humanity is changing. In partic-
ular, most demographic growth is happening in parts of the
world with low levels of per-capita cereal consumption and,
other things being equal, this fact tends to weight downward
Abbreviations: FSU, former Soviet Union; KU, European Union; ha,
hectare.
*To whom reprint requests should be addressed. e-mail: T.Dyson@
lse.ac.uk.
5929
OCR for page 5930
5930 Colloquium Paper: Dyson
Kgs 400
an
qn~
x annual production
.
t950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
Year
FIG. 1. World per-capita cereal production, 1951-1997. Averages
for 1952 and 1996 are calculated from data for 1951-1953 and
1995-1997, respectively. Here and subsequently cereal data are ex
pressed in production terms. Principal data sources: refs. 4 and 5.
Adapted from ref. 2.
the average level of world per-capita cereal consumption (and
hence production).
Regional Cereal Production Trends. A better picture
emerges if regional trends are considered. The present work
arranges the world's countries into seven regions (see ref. 2 for
details). Six appear in Fig. 2. I discuss them in turn.
Sub-Saharan Africa has done very poorly in terms of food
production. The explanation has many sides, but it includes
ethnically heterogeneous nation states, widespread political
Sub-Saharan Africa
Kgs 200 1 ~annual production Kgs 350
5 year average
300 ~1
1 50 ~
Proc. Natl. Acad. Sci. USA 96 (1999)
instability, neglect of agriculture by governments, and, despite
its many health problems (including the AIDS epidemic),
extremely rapid population growth. The distinctiveness of
crops and farming methods in this region also has meant that
it has often missed out on "Green Revolution" technical
developments (e.g., relating to high-yielding varieties of wheat
and rice) that have boosted agricultural production elsewhere.
Around 1995 this region's average per-capita cereal output was
only about 146 kg, which is a low figure, even allowing for the
fact that cereals are not grown in much of middle and west
Africa, and average levels of per-capita cereal consumption
were only slightly higher because of cereal imports and aid. Fig.
2 shows a generally declining trend in per-capita output from
the 1960s onward. There are also signs of heightened harvest
variability. The droughts of 1983, 1984 (when there was major
famine in Ethiopia), and 1992 are very clear.
The Middle East here combines North Africa and West
Asia. Fig. 2 shows that this region has experienced a significant
long-run decline in its per-capita output, which is not helped
by its rapid demographic growth. The annual volatility of the
harvest in this water-scarce area is also striking. Average levels
of per-capita cereal production during the l990s have fluctu-
ated between 250 and 270 kg, with no particular trend apparent
since the early 1980s. However, the Middle East imports large
quantities of cereals, mostly from North America. Around
1990 these imports accounted for almost a third of the region's
entire cereal consumption, and they raised the average level of
per-capita consumption to about 386 kg. These imports (which
Middie East
~ annual production
_ S year average
\; #:
250
_ ~ _ _
Nave ~X,%#~
# # \ \
# #
1' 50 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 19 50 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
Year Year
Kgs 250
2001
Kgs 700 1
65ol
Cool
550
50
450
ann _
In
South Asia
annual production
5 year average
Kgs 350 1
East and Southeast Asia
311 annual production
5 year average
300
200
1 50 1955 1960 1965 1970 1975 1980 1985 1990 1995 20C0 19 0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
V.~;ar Year
Europe/FSU
annual production Kgs 1500 ~annual production
5 year average 5 year average
North America / Oceania
I#;^
# # J ~ # `~
1950 1955 1960 1965 1970 1975 1980 1 9R5 1990 1995 2000 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
Year Year
FIG. 2. Per-capita cereal production by world region, 1951-1997. Averages for 1952 and 1996 are calculated from data for 1951-1953 and
1995-1997, respectively. Principal data sources: refs. 4 and 5.
OCR for page 5931
Colloquium Paper: Dyson
often are used to feed livestock) can be seen as an oblique way
of importing water.
South Asia mainly comprises the populous countries of the
Indian subcontinent (India, Pakistan, and Bangladesh). The
trend in Fig. 2 is dominated by India, which contains around
70% of the region's people. The 5-year curve shows the effects
of significant famines in the mid-1960s and early 1970s, which
cost lives. But during the last two decades there has been no
major food crisis, and average levels of per-capita cereal output
have risen to around 225 kg in the mid-199Os. Notice that
despite the plateau of the 1990s, levels of per-capita production
are still significantly higher than those of the early 1980s. Note,
too, the hint of a remarkable recent reduction in harvest
variability.
East and Southeast Asia is dominated by China, although it
includes other major populations, especially Indonesia and
Japan. This region's trend in Fig. 2 clearly reflects the agri-
cultural output losses of China's calamitous "leap" around
1959-1964, when perhaps 20 million-30 million died in famine.
However, the subsequent trend in per-capita cereal production
generally has been upward. Notice the sharp acceleration after
the agricultural policy reforms that were introduced in China
around 1978. This acceleration also reflected the introduction
of hybrid rice and, still more, large increases in the use of
chemical fertilizers by Chinese farmers. This region has con-
tinued to experience a rise in average per-capita cereal output
since the early 1980s, albeit at a slower rate. By the mid-199Os
regional production averaged about 316 kg per head.
It is obvious that the last two regions in Fig. 2 hold the key
to the decline in world per-capita output since 1984. The first
is Europe, here including the countries of the former Soviet
Union (FSU). The second is North America/Oceania, a hybrid
region, essentially comprising the traditional major cereal
exporters of Canada, Australia, and, above all, the United
States. Both of these regions produce cereals in comparative
abundance. In the mid-1990s the average per-capita output in
Europe/FSU was about 530 kg, and the figure for North
America/Oceania exceeded 1.2 tons per person. Although the
U.S., Canada, and Australia together contain less than 6% of
the world's population, they currently produce about 20~o of
the global cereal harvest.
To understand why Europe/FSU and North America/
Oceania both have experienced recent declines in per-capita
cereal production requires a little history. In brief, the story is
as follows. In the decades after the Second World War, until
the 1970s, the countries of Western Europe, particularly those
that now form the European Union (EU), were major net
cereal importers from the three traditional exporters of North
America/Oceania. In the 1980s this situation changed, because
the KU, with its heavily protectionist Common Agricultural
Policy, rapidly emerged on the world stage as a significant rival
cereal-exporting bloc, which offloaded cereal surpluses on the
international market at heavily subsidized prices. In turn, this
provoked retaliatory responses from the traditional cereal
exporters, especially the U.S., and by 1990 world grain prices
were exceptionally low, at roughly 60% of their 1980 level.
Neither of the key players in this drama (the U.S. and KU)
could avoid the fundamental logic of the situation. Accord-
ingly, both have had to introduce policies designed to reduce
cereal support costs, decrease stocks (which are expensive to
maintain), and reduce their cereal cropland through the idling
of significant areas of land. That said, the policy response has
been much swifter in the United States (and Canada and
Australia) than in Europe. Because many European countries
benefit from the Common Agricultural Policy the policy has
been hard and slow to change. Indeed, the chief cause of the
really precipitate recent decline in per-capita cereal output
shown in Fig. 2 for Europe/FSU lies elsewhere. The main
explanation for the cereal output collapse of the 1990s has
been the massive economic and political disruption resulting
Proc. Natl. Acad. Sci. USA 96 (1999J 5931
from the fall of communism in eastern Europe and the FSU.
Consider, for example, that in 1990 the Soviet Union had a
near-record cereal harvest of 227 million tons, but by 1995 the
component countries of the FSU produced only 122 million
tons of cereals. A decline of 105 million tons is roughly
equivalent to losing production equal to about 4 years of
growth in world cereal demand.
Finally, a word is in order regarding Latin America, the
region not shown in Fig. 2. Levels of per-capita cereal output
in Latin America are relatively low, around 260 kg in the
mid-199Os (although cereals are probably a poorer proxy for
food in general here than is the case for any other developing
region). The trend for Latin America is actually very similar to
that shown for North America/Oceania in Fig.2. In particular,
per-capita cereal output declined from a peak in the early
1980s to a trough around 1990, and then there was a period of
limited recovery in the 1990s. The explanation for this simi-
larity of trend is the common influence of international market
conditions, notably as they affected Argentina, which is the
region's second biggest cereal producer (after Brazil) and the
largest exporter by far. Confronted by a steadily deteriorating
world price, Argentina's farmers had little choice but to shift
large areas of land out of wheat in the 1980s.
Concluding Remarks on Recent Trends. I conclude this
review of past trends with six comments.
First, it should be clear that world cereal production has
grown more slowly than population growth chiefly because of
deliberate policies and political developments in North Amer-
ica/Oceania and Europe/FSU. With the exception of Latin
America (a special case) average per-capita cereal output in
the mid-199Os exceeded that in 1984 in all other world regions.
It is especially noteworthy that the two large Asian regions,
which together contain 57% of humanity, both have experi-
enced significant rises in per-capita cereal production.
Second, those who point to a "dramatic slowdown" in world
cereal yields (see ref. 7, p. 142) are mistaken. Fig. 3 shows that
the trend is more or less linear, or "arithmetical" to use
Malthus' term. Of course, on a rising base this linear trend
translates into a declining percentage increase, but that is
inevitable. There was a brief yield pause in the early 1990s,
largely because of major yield declines in the former commu-
nist states of Europe/FSU. But in the last few years the global
yield has resumed its upward march. My earlier research (2)
took the world yield around 1990 of 2.711 metric tons per
hectare (ha) and projected it forward by using the average
slope of +42.6 kg/ha per year experienced during 1981-1993.
This procedure implies a 1997 yield of 3.009 tons/ha, only very
slightly higher than the actual yield of 2.979 tons (see ref. 6~.
Inasmuch as anything can be gleaned about regional yield
trends in the brief period since 1993, then sub-Saharan Africa
and the Middle East have done poorly. But both South Asia
and East and Southeast Asia have performed much as pro-
jected on the basis of their yield trends during 1981-1993, and
3 0
2.5
c)
- 2.0-
c
c 1.5
o
c)
-
a'
~ 10
~/
,J
-
,,,, I,,,, I,,, . I ., . . I .,,, I,,,, I,,,, 1 1 1
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000
Year
FIG. 3 World cereal yield, 1951-1997. Principal data source: ref. 5.
OCR for page 5932
5932 Colloquium Paper: Dyson
Latin America and North America/Oceania have done better
still. It is important to appreciate that it is inevitable that there
is annual fluctuation in the world yield. And periods of plateau,
particularly in certain locations and for specific crops, are an
integral feature of overall yield advance. Thus, with generally
low international prices, the 1990s have seen indifferent yield
performance for wheat. We cannot be complacent, but there
is no particular cause for concern about recent world cereal
yield trends.
Third, the basic relationships linking volumes of world cereal
stocks, world cereal aid donations, and international cereal
prices during recent decades are fairly clear. Fig. 4 shows that
stock and donation levels have tended to vary directly with
each other and inversely with prices. After my preceding
discussion of the recent rivalry between the U.S. and KU,
notice how the level of world cereal stocks has fallen sharply
since the peak of the 1980s, largely because of their shared
policy need to run down the size of their publicly held stocks.
This common policy objective may partly explain why in the
early 1990s cereal aid donations were somewhat higher than
might have been anticipated given previous experience. How-
ever, a more important part of the explanation was the sudden
appearance of new recipients for aid, i.e., the collapsed former
communist states.
Fourth, of course, we do not live by cereals alone. There is
considerable evidence that in most world regions human diets
have become more diverse since the early 1980s (e.g., see refs.
8 and 11~. As living standards generally have risen and
populations have urbanized, so consumption and production
levels of fruit, vegetables, livestock products, and processed
foods all have tended to rise, too. In this context the Food and
Agricultural Organization calculates indices of per-capita food
output, which use price data to weigh estimates of the pro-
duction quantities of all the main types of food. For the
developing world as a whole this index was 114 in 1990-1992
(1979-1981 = 100; see ref. 12~; only for sub-Saharan Africa do
these indices suggest that food output has not been able to keep
up with population growth. Increases in noncereal food output
have been especially marked in South Asia (a corresponding
index of 117) and, still more, East and Southeast Asia (index
of 128), reflecting significant gains in India and China, respec-
tively. So the evidence is strong that in most parts of the world
human diets have been becoming more varied. And in many
locations cropland that has been shifted out of cereals, because
of their low relative prices, has been switched to grow other
food and nonfood crops.
Fifth, both the frequency and demographic impact of fam-
ines have been considerably reduced, which is part of the
message from Fig. 2. However terrible they may be, recent
-30 0 -14
20 ~ _
o- - 8 '
- ~ 5 0 o'
~ _5m
400
350
300
cn
O. 250-
Q]
c
200
1 50
~5
-
C)
1 00-
50- ~
1960 1965 1970
· Annual wheat price
...... Wheat price,
3 year average
1975 1980 1985 1990
· Annual cereal stock
Cereal stock,
3 year average
to c
' 1 1 ..
1 995
Year
0 Annual cereal aid donations
Cereal aid donations,
3 years average
FIG. 4. World cereals: prices, stocks, and donations, 1960-1997.
Principal data sources: refs. 3 and 8-10. Adapted from ref. 2.
Proc. Natl. Acad. Sci. USA 96 (1999)
events in places like North Korea and southern Sudan are
probably less than those that engulfed countries like Mozam-
bique and, certainly, Ethiopia in the 1980s. And they are
certainly small compared with the major famines of the early
1940s, or the Chinese calamity around 1960. From all of these
cases it is obvious that warfare and dislocation arising from
political upheaval are the chief causes of famine in the modern
world. The role of agricultural production failure, by itself, is
comparatively small. Moreover, nowadays ways to combat
what is usually the principal proximate cause of famine deaths
(epidemic disease) generally are improved, although they
cannot always be implemented. Today famine has become
largely a sub-Saharan tragedy, and even there one authority
has described the chances of an African dying in a famine as
"vanishingly small" (see ref. 13, p. 31~.
Finally, for two reasons, we now may be entering an era of
rather greater international cereal price volatility than has
prevailed for some time. One reason is the lower level of world
cereal stocks, itself conditioned by the recent policies of the
U.S. and KU. Undoubtedly, this lower stock level influenced
the sudden cereal price rise of 1996, although it is worth noting
that even in 1996 the international price was probably no
higher than in 1985 or 1989 (see Fig. 4~. It may be that any
"trigger point" of world cereal stocks, below which some
writers (14) suggest grain prices will become more variable, has
shifted downward. The second reason is the worrying rise of
cereal harvest volatility in North America. It should be stressed
that for five of the seven regions in this study there are no signs
of any increase in cereal harvest variability (see ref. 2~. Indeed,
for South Asia I already have remarked on a seeming recent
diminution of harvest fluctuations, which are related to a series
of good monsoons, which may be a beneficial result of climate
change. Sub-Saharan Africa has experienced a long-run rise in
harvest volatility, but this rise has a negligible impact on world
output because the region produces less than 5% of the global
harvest. However, just a glance at Fig. 2 reveals the major rise
in North America's harvest volatility. This rise is important
because the region is still the main supplier of cereals to world
markets. This increased volatility in North America is largely
weather-induced (witness the output declines of 1983, 1988,
1993, and 1995), and it is possibly a negative result of climate
change.
The Future: Cereal Demand and Supply
So, although not without problems, recent trends have not
been as dismal as they sometimes are portrayed. And, in turn,
this conclusion allows me to make some speculations about the
future that are more upbeat than downbeat, though with
elements of both beats. Inevitably, what follows is very broad-
brush, and it involves a mixture of projection, extrapolation,
and judgment (for more detail and qualification see ref. 2~. I
first will examine the evolution of world cereal demand, and
then consider supply.
Although there are different approaches to estimation (see
ref. 15) there is little doubt (i) that since the 1950s population
growth has been responsible for a rising share of world cereal
demand growth, and (ii) that population growth will be the
chief cause of cereal demand growth in the period to 2025.
Table 1 gives some illustrative calculations based on the United
Nations' 1996 "medium variant" (essentially best-guess) pop-
ulation projections to the year 2025. And following my earlier
work, I use 1990 as the base year.
Table 1 shows that in the period to 2025 the world's
population is expected to rise by just under 800 million per
decade, to slightly over 8 billion. The largest absolute addi-
tions, by far, will occur in South Asia and sub-Saharan Africa.
These are regions of low per-capita cereal production and
consumption, but together they account for more than 55% of
the total anticipated demographic growth. An initial calcula
OCR for page 5933
Colloquium Paper: Dyson
Table 1. Regional projections of population and cereal demand (millions of tons) 1990-2025
Proc. Natl. Acad. Sci. USA 96 (1999' 5933
Population, Projected cereal demand in 2025
millions Cereal consumption in 1990 based on
Volume, mill. PopulationPopulation
Region19902025 Per capita, kg tons increase onlyplus income
Sub-Saharan Africa4901,197 150 73.6 179.8179.8
The Middle East276534 386 106.6 206.4231.9
South Asia1,1932,021 237 282.2 478.1549.7
East and Southeast Asia1,7942,387 338 605.8 806.21,040.9
Latin America440690 265 116.6 182.7217.9
Europe/FSU788799 634 499.3 506.5506.5
North America/Oceania304410 780 237.1 319.5319.5
World5,2858,039 363 1,921.3 2,679.03 046.5
Following previous work (2), I retain 1990 as the base year for projection. The estimated demand on population plus income assumes no change
in per-capita cereal consumption in sub-Saharan Africa, Europe/FSU, and North America/Oceania. However, in the remaining regions rises are
assumed, taking average per-capita cereal consumption in 2025 to 434 kg (in the Middle East), 272 kg (South Asia), 436 kg (East and Southeast
Asia), and 316 kg (Latin America). For details of the basis of these assumptions see ref. 2. Principal sources: refs. 2, 4, and 5.
tion of the volume of world cereal demand in 2025 holds
per-capita cereal consumption constant in each region (at the
levels prevailing around 1990) and then projects demand
forward solely on the basis of the anticipated population
growth. Table 1 shows that on this population-increase-only
assumption, world cereal production must rise from around
1.921 billion tons in 1990 to about 2.679 billion in 2025 to match
the rise in demand. Note, too that, on this basis, world
per-capita cereal production would fall to 333 kg (2,679/8,039)
simply because of the changing regional composition of hu-
mankind (i.e., even though per-capita consumption levels
would stay constant in each region). This fall illustrates my
previous point that very different regional rates of demo-
graphic growth have implications for global cereal demand
that, to the extent that demand stimulates supply, are weighing
downward average levels of world output.
Of course, levels of per-capita cereal consumption will not
remain constant. Rising incomes will increase levels of con-
sumption in some regions; although, in others, health concerns
about eating meat could reduce levels of per-capita intake.
Also, factors like population aging and urbanization could
exert a modest influence on the evolution of future world
demand. Although no one can predict how these factors will
evolve, a second set of calculations can capture some of the
broad implications. Accordingly, I believe it plausible to
assume some continued rise in overall per-capita cereal con-
sumption in the Middle East, South Asia, Latin America, and,
most importantly, East and Southeast Asia. Essentially, this
computation has been done by means of a considered extrap-
olation from the corresponding regional per-capita cereal
consumption trends of the period 1970-1990 (see ref. 24. The
resulting average levels of per-capita cereal consumption in
2025 assumed here for the four regions are given in the notes
to Table 1. However, the poor record of sub-Saharan Africa
means that I have retained the assumption of constant per-
capita consumption for this region. And the same applies for
both Europe/FSU and North America/Oceania, although
here my rationale is that levels of per-capita consumption are
unlikely to rise from those prevailing around 1990, and they
could even decline (for example with a reduction in demand
for livestock products). The conjectural nature of these cal-
culations should require no emphasis. However, the popula-
tion plus income column of Table 1 suggests that roughly 3
billion tons of cereals will have to be produced in 2025 to match
the volume of world cereal demand.
Can the world's farmers produce 3 billion tons for 8 billion
people in 2025? Preliminarily, the evidence already reviewed
suggests that they probably can, or, at least, something very
close to it. Although the trend in world per-capita cereal
output is rather misleading (partly because the regional com
position of humanity is changing) the trend in the world cereal
yield (see Fig. 3) is more telling, because the regional com-
position of the world's harvested cereal area has changed less.
And, clearly, it is yields that hold the answer to future world
food production. If from 1990 we extrapolate the world cereal
yield in Fig. 3 on the previously mentioned average increment
for 1981-1993 (of 42.6 kg/ha per year) then the average yield
in 2025 will be around 4.20 tons. And coupled with the world
harvested cereal area around 1996 (of about 702 million ha)
this yield alone would produce 2.95 billion tons of grain. Even
by using the average increment experienced since 1990 (of
about 38.3 kg/ha) gives a yield of 4.05 tons in 2025 with
corresponding output of 2.85 billion tons. Moreover, these
calculations do not allow for any increase in harvested cereal
area. Furthermore, here I have projected demand and supply
independently, but, of course, in the real world they continually
interact. The scope for adjustment between the evolution of
global cereal demand and supply, e.g., in terms of changes in
consumption patterns, or areas of cropland sown with cereals,
is considerable. However, again, matters are better considered
at the regional level.
Accordingly, Table 2 summarizes some simple calculations
regarding regional yields. I stress that they are not meant as
detailed projections, but rather as a backcloth for discussion.
Again 1990 is taken as the base year. The first two columns
provide the regional cereal areas harvested and corresponding
yields around 1990. The third column gives the average annual
increments in yield experienced over the period 1981-1997,
broadly the period for which some authors (7) claim to detect
major problems in world cereal yield growth. The fourth
column shows what the regional cereal yields will be in 2025 on
the assumption that the average increments experienced for
1981-1997 continue into the future. The fifth column gives the
corresponding levels of cereal production in 2025 on the
assumption that the areas harvested remain constant as around
1990. And the final column shows the regional shortfalls or
surpluses implied when these production figures are compared
with the previous projections of demand.
The broad picture that emerges from Table 2, to which I fully
subscribe, is that there is going to be an increasing degree of
regional mismatch between the expansion of demand and the
capacity to meet that demand. In general, the world's devel-
oping regions are going to increasingly depend on cereal
imports, both in absolute terms and as a proportion of their
total consumption. So the volume of world trade in cereals
must rise, probably more than doubling between 1990 and
2025. The U.S., Canada, and Australia will continue as the
main source of cereals for world markets, but increasingly they
will be joined in a subsidiary role by Europe/FSU. Notice that
even on these rough illustrative assumptions the total global
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5934 Colloquium Paper: Dyson
Table 2. Projected cereal yields and production in 2025 by region
Proc. Natl. Acad. Sci. USA 96 (1999J
Projected
Average annual production
Average area cereal yield on the basis Shortfall/surplus
harvested increase, kg/ha of constant compared to
1989-1991, Average yield, per year Linearly projected area, projected
Region million ha 1989-1991 1981-1997 yield 2025 million tons demand
Sub-Saharan Africa 59.3 1.165 10.6 1.536 91.1 -88.7
The Middle East 40.2 1.642 23.6 2.468 99.2 -132.7
South Asia 140.3 1.919 52.0 3.739 524.6 -25.1
East and Southeast Asia 145.1 3.817 70.9 6.299 914.0 -126.9
Latin America 48.4 2.119 40.5 3.537 171.2 -46.7
Europe/FSU 171.4 2.816 22.8 3.614 619.4 + 112.9
North America/Oceania 98.4 3.734 55.4 5.673 558.2 +238.7
World 703.1 2.711 39.0 4.076 2,977.7 -68.5
The total 2025 cereal production figure given above is the sum of the regional figures, as is the total shortfall. I stress that the above figures are
simply a backcloth for discussion. They are based on the unlikely assumption of no change in harvested cereal area. A quantitative integration of
broadly plausible area changes is available elsewhere (see ref. 2~. Principal sources: refs. 2, 4, and 5.
shortfall is only 68 million tons; although, to reiterate, there is
considerable scope for adjustment. I now look briefly at the
prospects for each region.
Sub-Saharan Africa is unlikely to see much improvement in
its overall food situation. The population is expected to more
than double between 1997 and 2025, but there is nothing in the
region's agricultural history to suggest that it will increase its
food output to meet the demographically driven expansion of
demand. Average yields may not rise much, and despite the
assumption of Table 2 increases in food output often will come
from an expansion of the cropland area. It seems highly
unlikely that the annual volume of cereal imports (including
cereal aid) will increase to anywhere near 88 million tons by
2025. Only a minority of countries will be able to afford to buy
sizable amounts of food, and this fact alone may reduce much
of any 68 million ton global shortfall such as is implied by Table
2. It is conceivable that per-capita food consumption in the
region could decline. Surely, and above all, sub-Saharan Africa
deserves attention and assistance, both apropos agriculture
(on the supply side) and reproductive health/family planning
(on the demand side). Moreover, despite all of its problems, it
is important to acknowledge the region's tremendous poten-
tial. Furthermore, there are some encouraging recent devel-
opments, like falling birth rates now in most countries, and
signs (admittedly very weak) of a democratic wave, notably, but
not only, in South Africa (164. In the long run progressive
political change may be vital for helping to solve this region's
many problems.
The Middle East certainly will depend even more on cereal
imports in the next few decades. Indeed, it is perfectly possible
that this region could be meeting half (or more) of its total
cereal consumption through imports by 2025. Water con-
straints and population growth are parts of the explanation for
this situation. Most countries in the region are likely to be able
to finance most of their imports. For example, some have oil
reserves or benefit from tourism. Other countries, such as
Egypt, will finance their imports partly through the export of
specialist foods to Europe, where they already provide rising
competition for growers in locations like Spain and Greece.
However, Sudan is one major country that will almost certainly
have difficulty in purchasing sufficient cereal supplies. And
Sudan is a vivid reminder of the region's general political
instability, which could profoundly affect national levels of
food security in the coming decades (for a quantitative attempt
to integrate socio-political stability into estimates of national
food security see ref. 2~.
South Asia emerges from Table 2 with the smallest projected
regional cereal shortfall, whether measured in absolute or
proportional terms. There are several reasons for thinking that
this region will not develop a huge cereal import requirement
despite its considerable future population growth. First, there
is South Asia's current low level of per-capita cereal consump-
tion, which remains comparatively low even if a significant
increase during the period to 2025 is incorporated. Of course,
this outlook is not a happy consideration, because it reflects
widespread undernourishment, but it is a fact. Second, there is
the commonly prevailing vegetarian diet. This diet may dimin-
ish, especially in urban areas, thereby raising the indirect
consumption of grain. However, vegetarianism certainly will
stay as a strong influence in the next few decades, and it will
restrain the growth of total cereal demand. A final reason
cereal imports may rise only modestly in the coming decades
is that the current average regional yield is low, suggesting
scope for improvement. Note in Table 2 that even the linearly
projected cereal yield for 2025 is below that which prevailed in
East and Southeast Asia around 1990. Much of the recent, and
future, rise in South Asia's yields will come from greater use
of chemical fertilizers. For example, in India the level of annual
applications has risen from 49 to 80 kg/ha of cropland between
1984 and 1994, and a similar story applies for both Pakistan
and Bangladesh (see ref. 3~.
Table 1 suggests that East and Southeast Asia is the only
region where, especially given the presence of China, future
economic growth could have a broadly comparable impact on
the growth of total cereal demand as will future population
growth (of course, this region's demographic growth is rapidly
slowing). So, irrespective of the numbers in Table 2, it seems
very probable that East and Southeast Asia will have the
largest absolute cereal import requirement of any region in
2025. That said, there seems to be no particular reason for
alarm regarding the growth of China's cereal demand. The
country has important agricultural potentials (e.g., the up-
grading of grasslands); until recently its cropland area probably
has been seriously underestimated and, relatedly, its yields
overestimated (see e.g., refs. 17 and 18~. China's recent
performance in raising cereal yields has been, and continues to
be, strong. Finally, the country's political leadership is very
aware of the importance of increasing national food output as
demand rises (recall the characters at the beginning of this
paper). So when some people (19) ask "who will feed China?"
The answer is plain: mainly, the Chinese. Chink and East and
Southeast Asia as a whole will significantly increase their
volumes of cereal imports but almost certainly not to the
massive levels that some (7, 19) have suggested. Again, as
everywhere, socio-political stability will be a crucial ingredient
for continuing food security. And if this component is factored
in, then by some reckoning China may be no more food secure
than India, despite its better agricultural performance (2~.
Latin America has relatively favorable prospects. Of course,
some countries (e.g., Peru and Bolivia) have major food
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Colloquium Paper: Dyson
problems. And in most countries there are significant food
difficulties arising from inadequate purchasing power among
poorer sections of the population (although overnutrition is an
increasing problem in much of the region, too). However, the
region as a whole is comparatively advanced, demographically,
economically, and politically. As previously intimated, focus-
ing on cereals can be misleading because Latin America is a
major producer and exporter of products like sugar, soybean,
meat, coffee, cocoa, and vegetables. Should cereals become
more profitable in the decades ahead then Argentina and
perhaps Brazil could become significant cereal exporters, for
example, to China.
Finally, this brings me to the two main exporting regions,
Europe/FSU and North America/Oceania.
Table 2 implies annual net cereal exports from Europe/FSU
exceeding 110 million tons by around 2025, which seems
plausible. Note that this surplus results from extrapolating the
very modest annual yield increment of only 22 kg/ha per year
experienced during 1981-1997. The small size of this incre-
ment was almost entirely the outcome of the yield collapse
experienced in Eastern Europe and the FSU. In fact, an
average increment closer to 47 kg for this region is perfectly
credible over the longer run (see ref. 2~. There will be
continued major yield rises in the KU. Here are two recent
illustrations: between 1989-1991 and 1995-1997 France's av-
erage cereal yield rose from 6.24 to 6.81 tons, and the United
Kingdom's, from 6.17 to 6.98 tons. Consequently, the amount
of idled cereal land in the EU may well be raised, although it
also could be reduced (i.e., more land could be brought into
cultivation if the need arose). In addition, there is great
potential to raise cereal production in Eastern Europe (notably
Poland) and large areas of western Russia, Ukraine, and
Kazakhstan in the FSU. Undoubtedly, reforming the farming
sector in most of these former communist countries is proving
to be a lengthy and extremely difficult process. It is compli-
cated by issues of access to European markets and applications
for EU membership. In turn, these issues raise the important
problem of Common Agricultural Policy reform.
Finally, the capacity for continued cereal yield and output
growth in North America/Oceania is also strong. Again,
comparing averages for 1989-1991 and l99S-1997, and in
increasing order of export importance, cereal yields rose from
1.66 to 1.91 tons/ha in Australia, 2.47 to 2.69 tons in Canada,
and 4.58 to 5.04 tons in the U.S.. With an average yield for the
region of 4.08 tons in 1995-1997, an average of around 5.5 tons
in 2025 seems to be a realistic target. Indeed, the average
regional yield in 1994 was nearly 4.5 tons [assisted by good U.S.
Out-turn for maize Scorned. To reiterate, a greater problem
apropos production in this region may be increasing harvest
volatility, with obvious implications for world prices. The other
regional prospect of which we can be sure is that there will be
continued agricultural rivalry with the KU, which will extend
far beyond cereals.
Conclusion
Inevitably this paper has omitted a lot, and one's view as to
whether the prospects to 2025 are good or bad depends partly
on the particular criteria that are used. Surely the prospects are
mixed. However, in my view, over this specific time horizon,
they are more good than bad.
In 2025 the world's farmers will be producing roughly 3
billion tons of cereals to feed the human population of around
8 billion, which will require an average world cereal yield of
about 4 metric tons/ha (see also ref. 20~. It also is likely that
some regions will, for different proximate reasons, experience
an increase in their harvested cereal area. For example, in
sub-Saharan Africa with meager yields this increase may
happen because of population growth, whereas in Latin Amer-
ica it could happen to meet export demand.
Proc. Natl. Acad. Sci. USA 96 (1999) 5935
We know that there are significant problems of soil structure
when land is cultivated year after year (e.g., see ref. 24~. But
problems of water for agriculture probably will be much more
important. World agriculture will have to use its water supply
very much more efficiently in the coming decades. And water
is a resource that must be better priced.
Of course, there will be new crops and improved seeds. But
most of the required increase in the world's harvest will come
from the application of procedures and knowledge that we
already have to the current world harvested area. It is ines-
capable that humanity will depend even more on synthetic
nitrogen fertilizers for its food supply (e.g., see ref. 21~. My
calculations using Gilland's equations (22) suggest that there
may have to be an approximate doubling of global use of
synthetic nitrogen to produce 3 billion tons of grain (2~.
Another vital resource for the future will be a continuing rise
in the level of population, and hence farmer, education in most
regions. And farming everywhere is likely to involve much
greater dependence on information-intensive farm manage-
ment procedures, as well as heightened attention to variation
of conditions within individual fields, whether done through
the reading of subtle color change in crop leaves or by satellite
Imagery.
It is highly unlikely that there will be any wonder break-
through that will solve the problem of raising world food
production. On the contrary, it will continue to be hard work.
Moreover, the process of raising yields and agricultural ad-
vance is extremely complex. Many of the multitude of devel-
opments that together will influence the world food outlook
(e.g., relating to education, health conditions, technology,
transport and communications, and institutional structures)
primarily are fashioned by the wider world, i.e., beyond
agriculture itself.
Crucial among these will be developments in the realm of
political economy. Almost everywhere socio-political stability
will be the most important element for maintaining food
security in the future. I have noted the importance that
political reform could have in sub-Saharan Africa over the
longer run. Then there is the issue of how the situation in
Eastern Europe and the FSU (and reform of the Common
Agricultural Policy) will unfold. There is also the related
matter of international trade arrangements, where it seems
probable that the momentum toward increasing liberalization
will be maintained. Partly for this reason, it is hard to envisage
that average world food prices will be higher in 2025 than
applied, say, in the early 1990s (see ref. 23), although prices
could well be more volatile.
There will still be many hungry people alive in the year 2025.
But if the scenario envisaged by this paper applies, then there
must be a reasonable chance that the absolute number will be
fewer than is the case today. Also, we should not lose sight of
the rapidly growing problem of overnutrition in some urban
areas of the developing world. However, the very substantial
demographic growth that will happen in the world's worst-fed
regions almost guarantees the continuation of a considerable
volume of undernourishment. Significant areas, especially in
sub-Saharan Africa, may effectively remain "lost" to develop-
ment, including agricultural development. In such locations
population growth will contribute to environmental damage as
people try to eke out a bare living from the land.
In conclusion, the main thrust of this paper has been to show
that, in general, the world food situation has been improving.
And I have argued that this trend probably will continue during
the next few decades. World food output will continue to rise,
although there will be a growing degree of mismatch between
the expansion of food demand and the capacity to supply that
demand. Accordingly the balance will be met by a considerable
expansion of the world food trade. As a result, most people
probably will be better fed in 2025 than is the case today.
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5936 Colloquium Paper: Dyson
This work was funded partly by the United Kingdom Economic and
Social Research Council (Economic and Social Research Council
Award L320-27-3024~.
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.
\
Representative terms from entire chapter:
cereal production
