Reinventing Malthus for the 21st Century: 

A Bicentennial Event on Malthus' Original Population Essay 

 

A presentation sponsored by 

Negative Population Growth (NPG) and The Federation for American Immigration Reform (FAIR)

held at National Press Club, Washington, DC, July 14, 1997 

 
 

Remarks from Lester Brown President, WorldWatch Institute

  
Thank you.  I knew John was an excellent writer, but I hadn't heard him speak before.  Wow! 

We were talking earlier, John, about when we started the Worldwatch Institute in 1974.  At that time, I had just finished a book called By Bread Alone.  It was a background book for the World Food Summit held in Rome.  When I got back from the conference, I was contacted by the Embassy of Tanzania asking if I would inscribe a copy for President Nyerere, which I happily did. I sent it to him, and sometime later I got a letter in which he noted a passage stating that probably not two political leaders in a hundred understand that a three percent annual rate of population growth means a twenty fold population increase in a century.  He said, "However many there were before, there is now one more." 

I mention this because I think so few people understand the insight that Malthus contributed on the nature of exponential growth.  There are a lot of examples that are used to teach this to school children.  One that the French use, and inspired the cover photograph on John's book, is the story of the lily pond ö in which there is one leaf on the first day, two the second, four the third and so forth. The question to the students is, if the pond fills on the thirtieth day, when is it half full?  And the answer is the twenty-ninth day of course.  That is the nature of exponential growth and I don't think we've quite grasped it yet.   

We are still trying to understand the magnitude of growth and its consequence, in part because the sort of growth we have experienced in recent decades has no historical precedent. When Malthus was writing the essay, the population growth that year must have been 0.2% or something like that.  I mean it was almost negligible.  Those of us born before 1950 have witnessed a doubling of world population growth. We are the first generation in history to have this experience.  Stated otherwise there has been more population growth since 1950 than during the preceding four million years from when we first stood upright.  I think it will be some time before we fully understand the consequence of what is happening.   

When I think of Malthus' writings and his warnings of 200 years ago,  I remember that the official number that was used at the Food Summit last November of the number of hungry and malnourished in the world, was 800 million.  The World Bank says there are 1.3 billion people in the world today who live on a dollar a day or less.  The chances are that almost all of them are malnourished and hungry at least for part of the year.  Although Malthus was controversial, he has not been dismissed as a person, as a thinker.  His name has become a common adjective.  I was trying to think of other people's names that have become part of our daily vocabulary.  Christian obviously, Marxist, Platonic, are some of the ones that come to mind, but Malthusian is very much a part of our vocabulary.   

I'd like to talk about two things that Malthus missed in his present forecast.  One is his underestimation of our capacity to raise land productivity.  Since 1950, the world grain harvest has nearly tripled and most of that increase has come not from expanding the area, but from boosting land productivity. Some countries have tripled or quadrupled wheat yield per acre, corn yield per acre, or rice yield per acre.  These are phenomenal advances.  If we look at grain yields historically in this country going back to the Civil War, which is as far back as we have data,  you see that from 1860 to 1940 wheat yield per acre and corn yield per acre are essentially flat. And then they both begin to take off and rise very rapidly.  Now, wheat is beginning to level off again.  In the efforts to raise land productivity, we have a  long historical plateau, a rapid rise, and then a tendency, at least, to level off again. 

Now there are a number of things that have contributed to the extraordinary rise in land productivity.  One would obviously be the advances in genetics.  Malthus was writing in 1798.  Mendel was doing his work in the early 1860's when he established the basic principles of genetics that set the stage for the exciting advances in plant breeding.  In an article in the July/August issue of Worldwatch Magazine we analyze the grain yield trends for various countries in the world historically, and look at the sources of the higher yields and try to get a sense of what we might expect in the future.   What the scientists have done to raise yields, is to increase the share of the photosynthate, that is the product of photosynthesis, going to the seed.  As the photosynthate is produced in the leaf, some of it is used by the leaf, some is used by the stem, some is used by the roots and some goes to seed.  In the originally domesticated wheats, on the Anatolian Plateau in Turkey, roughly 20% of the photosynthate  produced by the plant went to the seed.  In today's modern high yielding variety over half of the photosynthate goes to seed.  The upper limit is probably not more than 60%.  You have to have some photosynthate for the roots, for the stem and for the leaves in order for the plant to function.  So we are beginning to push against that limit and there doesn't seem to be any easy way to go beyond it.  We have not been able to change the efficiency of the product of photosynthesis itself.  That reduces to basic chemistry and physics.  And so it comes as no surprise that the rise in land productivity is now losing momentum.  

The two principal agronomic sources of higher yields have been fertilizer and water.  Just a half century after the essay appeared, Von Liebig, a German chemist, demonstrated in 1847 that all the nutrients that plants take from the soil could be replaced in mineral form.  That set the stage for what we now know as the fertilizer industry.  In 1950, the world farmers used 14 million tons of fertilizer ö nitrogen, phosphate, and potash, the famous NPK, the basic plant nutrients.  By 1990, they were using 140 million tons, a ten-fold increase.  The reason for using the fertilizer was to make sure that plants had enough nutrients to realize their full genetic potential. But after a point, more fertilizer doesn't make much difference. After the dramatic rise in fertilizer use in this country, fertilizer use has leveled off and actually declined somewhat since the early 1980's.  In the mid-1990's, farmers in this country are using less fertilizer than in the mid-1980's.  Fertilizer use has plateaued in Europe, the former Soviet Union, Japan and may now be about to do so in China. There comes a time when more fertilizer has very little effect on yield.   

The other major agronomical source of additional output has been growth in irrigation.  In  1950, there were about 94 million hectares in irrigation, today there are about 260 million hectares.  The growth in irrigation expanded öuntil today about 40% of the world grain harvest comes from irrigated land.  In Asia, of course, the overwhelming share of grain production is irrigated.  But what we are discovering is that this enormous growth in irrigation is in part based on the unsustainable use of water.  Aquifers are now being depleted; water tables are falling in the world's major food producing regions; including the southern great plains of the United States, the southwestern United States, several states of India including the Punjab, which is the bread basket of India, and much of central and northern China.  Just to site some of the more important examples.   

If we had been a far sighted species, we would have been monitoring the water tables. When the amount of pumping began to exceed the recharge of the aquifers, we would have stabilized the pumping.  But we didn't, so the pumping keeps going up ö the irrigated area keeps expanding, the aquifer keeps falling, and eventually when the aquifer is depleted, the rate of pumping will necessarily be reduced to the rate of recharge.  That's not a debatable point, that's a physical reality.   

And we are beginning to see that happen in some countries now.  In Saudi Arabia, a country that was pumping a fossil aquifer, grain production dropped 62% between 1994 and 1996.  After a gradual increase since 1979 we saw a dramatic fall, a classic overshoot and collapse situation.  Now that's much more dramatic than in most cases because that's a fossil aquifer, it doesn't recharge, once you pump it dry that's it.  But it is an example of what will be happening in the years ahead, as we begin to deplete more and more of the major aquifers on which we now depend for irrigation water.   

I think one of the most underrated resource issues in the world today is water scarcity.  Deforestation was easy.  You could film the burning rain forest. You could have graphic photographs of clear-cuts in the northwest.  Everyone understood deforestation.  But falling water tables are not very photogenic.  And so most people are just not aware of the extent to which the world is now depleting underground water supplies.  We are postponing the difficult decision for the next generation ö when the over pumping will be even greater and the number of people will be even larger.  

I was, over the weekend, making a list of postponed decisions that our generation is doing and leaving for the next generation.  Once you begin to make that list, you have to start worrying.  When water becomes scarce and the competition between cities and countryside intensifies ö as it is doing in China today, and throughout the Middle East and North Africa ö then cities pull water away from agriculture. The irrigated area is reduced and countries have to import grain to offset the loss of irrigation water.  To import a ton of wheat is to import a thousand tons of water.  Water scarcity is now beginning to shape international grain trade patterns in the same way that land scarcity did historically.  So water is emerging as a major constraint.  And in ways I don't think most people realize. As a result of beginning to approach the maximum amount of photosynthate that can go to seed, the maximum amount of fertilizer that plants can use and of pushing against water limits, we find that the rise in land productivity that had been so rapid for most of this last half century is now beginning to slow.  Now that's not to say that we will not further raise land productivity.  We will certainly in most of the world.  But it is becoming much more difficult.  This is why world grain stocks are now at the lowest level on record.  It is why all the land that was idled under commodity programs in this country is back in production.  We still have some land idled in the Conservation Reserve Program and some of that could be farmed sustainably with the right practices, but we are seeing a tightening of the world food situation and one that is likely to continue in the years ahead, for some of the reasons I have mentioned.   

So one of the things Malthus missed was this rapid rise in land productivity ö but I fear that we have come to take it for granted and to assume, as most economist do, that the trends of the last forty years are going to continue for the next forty years.  As one trained in the natural sciences I can assure you that will not be the case, but I don't think most political leaders are aware of how tight things could become.  Biotechnology would be great except that the biotechnologists have yet to develop a single high yielding variety of wheat, rice, or corn.  And the reason is that traditional plant breeders have done almost everything they can think of to do.  We are already pressing against the level of photosynthate availability for seed formation in large areas of the world. 

The second point that Malthus missed was the effect of rising affluence on the demand for food.  He talked about population growth and demand for food. People often say population growth is expected to double over the next half century, and therefore we will have to double food production. Rising affluence is now becoming a major factor.   

There is a big difference between how much grain is consumed per person in India and in the United States.  In India, it's about 200 kilograms a year, or roughly a pound a day.  When you have only that much grain, you can't convert a lot into animal protein; you have to consume almost all of it directly.  In this country we consume, largely in the form of livestock products, 800 kg of grain per year, or about four times as much.  We consume it in the form of pork, poultry, eggs, beef, cheese, milk, and yogurt ö all the things we like. But that's 800 kg of grain per year. The problem now is that the Chinese want to live like us; this is putting enormous pressure on the earth's resources.  China is not only the world's most populous country, but during the 1990's, it has been the worlds fastest growing economy.  Let me just site the annual growth rates for the last five years:  12 percent, 14 percent, 11 percent, 10 percent, and last year only 9 percent.  The United States was about 3 percent as I recall.  This means that incomes in China have gone up 60 percent in the last five years.  Much of this additional income goes to diversify diets, to get away from overwhelming dependance on one starchy staple, say rice, for most of one's food supply.  People do like a more diverse diet.  And so the Chinese are eating more pork, poultry, eggs and beef, and drinking more beer.  And it takes an enormous amount of grain.  I tell my colleagues at the Institute that multiplying 1.2 billion times anything is a lot.  Whether its another egg per person or another beer per person, it translates into a lot of grain. The official goal in China is to raise egg consumption from 100 eggs per person in 1990 to 200 eggs per person in the year 2000.  By that time there will be 1.3 billion Chinese.  That's 260 billion eggs.  How many chickens does it take to lay 260 billion eggs? The numbers are so huge they are humorous.  But they are real, and the real questions is how much grain will it take to produce 260 billion eggs.  John points out in his book that it will take as much grain as Canada exports to get from 100 eggs to 200 eggs in China.  There is no precedent for the growth in demand for grain that is occurring today in Asia.  I've talked about China because it's leading the region. 

India is also beginning to move up the food chain.  Poultry production is expanding by 15 percent a year, egg production I think 3 percent, and milk production by maybe 4 percent.  There are 970 million Indians beginning to move up the food chain.  We forget Indonesia, it only has 200 million people.  It sort of gets lost in Asia. But the broiler industry in Indonesia is doubling every six years.  So we are seeing an enormous movement of 3.1 billion people up the food chain in one region.  Excluding Japan the regional economy has grown by 8 percent a year on average for the last five years.  So affluence is also becoming a powerful source of additional demand for grain in the world.  When we went through the rapid shift to a grain-based livestock economy in this country, there were 160 million of us in the early years after World War II.  In Europe there were 280 million, but in Asia there are 3.1 billion and they are moving up the food chain faster than we ever did.  This is one point that Malthus missed, but it is an important one. 

As we monitor trends around the world ö soil erosion, climate change, deforestation, aquifer depletion, population growth, and rising affluence, my sense is that the slack is going out of the system.  I don't think business as usual is going to continue for much longer.  We have this infatuation with technology, which is understandable, whether it's exploring Mars or the internet and all the things one can do now in the telecommunications field.  It's fascinating, it's exciting, but it doesn't solve the food problem.  And it doesn't bring about the balance that we need between our continuously expanding numbers and the earth's resources, which have not changed very much since the time of Malthus.  We still have basically the same land area, the same water resources to work with. 

Thank you very much.