Can the world's existing farmlands provide enough crops to satisfy the hunger of the nine billion people—up from seven billion currently—that demographers predict will be living on the planet by the mid-21st century? Or will more and more forests and other ecosystems have to be cleared to feed all the extra mouths? A new study, published in Nature on August 30, suggests that increasing deforestation could be avoided provided farmers made better use of water and nutrients on land currently under cultivation around the globe. (Scientific American is part of Nature Publishing Group.)
The central premise of the new analysis is that intensifying agriculture where it already exists is the key to preserving a balance between farming and forests. To do that, the researchers from McGill University in Montreal and the University of Minnesota (U.M.) analyzed the so-called yield gap. That's the difference between what the highest yielding farm or area within a given region can produce—for example, corn—compared with what the average yield is. The difference between this best-practice farm and the average farm is the yield gap.
The researchers then employed national and regional agricultural data from outfits such as the Food and Agriculture Organization of the United Nations and the International Fertilizer Industry Association to determine the root causes of these yield gaps. Simply by improving fertilizer application and irrigation, the researchers find that global yields of corn, wheat and rice—the three main staple crops—could be increased by 64 percent, 71 percent and 47 percent, respectively.
"We are not claiming to diagnose the exact management practices needed on any particular plot of land," explains research fellow Nathan Mueller, who led the study from the U.M.'s Institute on the Environment, because local factors such as soils and weather can play an important role. Instead, the goal is to identify what practices might help close yield gaps at the regional or even global level and highlight those areas most in need of intervention.
That list includes the U.S. Great Plains and China, where more fertilizer is used than is strictly necessary. For example, American farmers apply so much fertilizer on Midwestern corn fields that much of it ends up running off, ending up in the Mississippi River and, ultimately, reaching the Gulf of Mexico. There the copious fertilizer fuels a bloom of algae and other microscopic plants that then die. Microbes that consume the dead plants also use all the oxygen available in surrounding waters, creating a vast "dead zone" that is devoid of sea life—an unfortunate side effect of the demand for more maize.
Lessening fertilizer use in the U.S. and China would free up nutrients to be applied to fields in eastern Europe and western Africa with no detriment to American or Chinese people. As it stands, the researchers estimate that some 11 million metric tons of nitrogen fertilizer and five million metric tons of phosphate could be saved annually at present without diminishing current yields. Those savings then could be applied to underachieving areas.
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Add CommentWhy do we want to feed 9 billion people by the middle of the 21st century? Why are we spending so much effort on insuring overpopulation of earth. In mid-twentieth century there were about 3 billion people. So in 100 years the population of earth triples? With 7 billion people, we're using resources faster than we can find them or synthesize them. With 9 billion, we're almost guaranteed to eliminate the last of earth's wildlife and pristine natural areas.
Reply | Report Abuse | Link to thisWe should spend our efforts trying to reduce the human population. It's the answer to all of our problems.
THe real problem - supposing you can grow enough food - is where are you going to get all the water to grow that food with and even more importantly supply the personal water requirements for each of those 9 billion. We are currently at 6 Billion and as a grown male has approx. 40liters of water in their body that's about (allowing for infants etc) about 400 cu.mi. of fresh water tied up in human flesh. Add in the water tied up in livestock and plant based foods needed to feed the current population and it must be many times that. Go to 9 billion and you're looking at around 600 cu. mi. of water.
Reply | Report Abuse | Link to thisScarcity is an invented disease. Don't live in fear land; there's plenty of grasses to eat like Nebuchadnezzar.
Reply | Report Abuse | Link to thisBasically, what you're saying is that the poor are too much of a burden on the rich so we should be culling them. Maybe if we weren't using drugs to bypass natural selection and in doing so embracing the weaknesses in our genome, the inbred children of monarchs wouldn't be so avaricious because they would die out.
Reply | Report Abuse | Link to thisThe world population is going to settle out at about 9 billion or so by 2050, but it's expected to start declining after that as more of the population by both raw numbers and portion will reside in urban areas where maternity rates are much smaller and often below replacement level. The reason for this is simple cost: it costs more in time and/or money to raise children in the city, so mothers tend to have fewer children than in rural areas where there is an economic incentive to bear more children. Satisfaction of family size is also a factor. Urban areas tend, when examined on a global basis, to have improved health due to a more educated populace, better sanitation, and improved access to medical care.
Reply | Report Abuse | Link to thisFor the last decade, the average world population growth rate has been between 1.2% and 1.1% and slowly declining. By mid-century, the rate is expected to be down to 0.5%, with further declines expected. Others have even earlier peaks around 2040 depending on how rapidly urbanized certain countries become. I, too, would like to see a much earlier peak, but I don't expect people to suddenly stop having children.
The current management practices, ruthless use of resources and subsidies fertilizer input creating lot of problems. The declining global water resources coupled these problems. There is more need of education and good grip on market forces to ensure global food security.
Reply | Report Abuse | Link to thisWhile the average population growth rate has been diminishing, populations in areas with the lowest nutritional resources are growing at alarming rates!
Reply | Report Abuse | Link to thisDuring the past 20 years, the world population has increased by 28%. During that period, the population of the African continent has increased by 58%, the Middle East by 53%!
http://en.wikipedia.org/wiki/Overpopulation
The population of India has increased by 235% over the past 60 years. It's population is now ~1.2 billion, while China's is >1.3 billion, but India is projected to become the world's most populated nation at nearly 1.4 billion by 2025.
If the entire world cannot control its birth rate children (and others) will increasingly suffer and die young.
I wholeheartedly agree with vernongoins and DougAlder.
Reply | Report Abuse | Link to thisOur past improvements in agricultural productions have become increasingly dependent on irrigation, fertilizer and automation, all of which consume large amounts of petroleum products.
Not only is current agricultural production highly dependent on diminishing natural resources, but complimentary nutritional resources appear to be approaching depletion, especially the enormous harvests of seafish that have fueled recent population growth. This factor can only increase future demand for agricultural products.
It's important to optimize our agricultural production, but I suspect this study has not included any consideration of reduced production resulting from impending climate changes, since they cannot be reliably predicted.
IMO, it's irresponsible to post such a comforting forecast that cannot include critical factors that will significantly influence the total availability of future nutritional resources. As long as we continue to rely on such rosy predictions there will be little pressure to reduce population growth!
The entire article is based upon the false premise that there is some responsibility for wealthy nations to care for people in less wealthy nations. That notion is something that has been invented fairly recently in the minds of some in western civilizations. Historically, there is no such responsibility and it is the responsibility for a nation to take care of its own citizens. If a nation has an unsupportable birth rate, why is that a problem for another nation to fix?
Reply | Report Abuse | Link to thisActually, birth rates have already declined a lot, but that won't impact population growth before the mid-21st century, because, since we increased our life-expectancy so much in the last century, all these youngsters aren't going anywhere soon.
Reply | Report Abuse | Link to thishttp://www.ted.com/talks/lang/en/hans_rosling_religions_and_babies.html
Another reason why developed nations are having lower birth rates is the dumping of hormone-mimicking pollutants into our water. More men have lowered sperm counts, more women are infertile. We might accidentally succeed in lowering our birth rates a lot more than we like! But less-developed countries also have misogynistic cultures that promote pregnancies whether the woman wants them or not (a la the Republican platform, note) which strongly contributes to the disparity in birth rates.
Reply | Report Abuse | Link to thiswater shortage kills the grasses too, you know. American midwest is having an acute hay shortage as well as corn dying from drought. And have you ever eaten grass? Humans can't digest it, whatever you think you read in the Bible. Some other weeds and wild plants, yes. ( I love lambs-quarters myself) Grass, no.
Reply | Report Abuse | Link to thispeople, per say are not the problem. over-consumption is. if you assume the current level of wasteful consumption of wastefully produced things, game over.
Reply | Report Abuse | Link to thisdaveJ--No you are wrong. It is the number of people that is the problem. The most environmentally sensitive person is the one who decided to not have children
Reply | Report Abuse | Link to thisYeah, and that is why we are dumping millions of gallons of precious irrigation water into producing whacky Corn Ethanol, which consumes more fossil fuel inputs then it replaces. In the Sandia Labs report on Water Usage, an avg 980 gals of irrigation fresh water per gal of ethanol produced:
Reply | Report Abuse | Link to this"...They found that bioethanol's water requirements... a gallon of ethanol may require up to over 2,100 gallons of water from farm to fuel pump..."
A corn ethanol fueled avg vehicle consumes 150 liters of water per km. A biodiesel fueled vehicle 600 liters of water per km.
Insanity!
Sorry Sisko but I can't agree with you. We're all citizens of the one and only planet we've got. If we don't act as if we're all in it together then we're likely to all go down together.
Reply | Report Abuse | Link to thisAnd that's before we even come to the ethical repsonsibility we have for each other. I'm not one anymore but I was brought up as a Christian, and for me Jesus's parable of the good Samaritan (for 'Samaritan' insert whoever you're most prejudiced against) is still one of the best answers to the question 'And who is my neighbour?'.
We also have a repsonsibility to all the other forms of life on Earth. If we don't keep our numbers to a reasonable level then we will cause the destruction of even more habitats, the death and suffering of even more living beings, the extinction of even more species, and the trashing of even more beauty.
The answer to overpopulation is to ensure that women and men have equality and men treat women with respect. We're still not there yet, though we're getting there slowly. The London Olympics were the first ever in which all countries - even Saudi Arabia - sent women athletes. If women live in a society in which everybody has access to a decent education, a decent living, political involvement, and a health service with access to contraception (and abortion as a necessary backup just in case) then the birthrate will fall. Most women (and in decent societies most men) only want two children - if they have more it's either because the woman doesn't have much choice, or because so many children die that they cannot be sure that they will have two children who survive into adulthood.
There is enough food to go round now. There are many reasons people starve, but one of the most central is that the world's resources are not shared out fairly.
Another reason is that many people eat too much meat from animals which have eaten plant foods which people could have eaten directly, a very inefficient way of producing food.
There has to be a limit sooner or later: the Earth must have a carrying capacity. A huge human population and climate change will mean sooner or later that there will not be enough food to go round.
Reply | Report Abuse | Link to thisThe limits to food production include the supply of nitrates in the soil, but there are other limits as well, such as adequate rainfall and good healthy soil. I don't see the use of synthetic nitrogen fertiliser as something to be avoided at all costs, but they're not the only way to get nitrates into the soil. There are plenty of nitrogen-fixing plants, and growing them is the most sustainable way of ensuring that nitrates aren't the limiting factor.
We need as well to increase the range of crops we grow, and especially to grow more perennial crops, which can be more resilient to water shortages and climate change. Agroforestry, especially forest gardening, could help us to survive.
http://en.wikipedia.org/wiki/Agroforestry
http://en.wikipedia.org/wiki/Forest_gardening
I empathize with most of your sentiments, but conscientious self discipline is not really effective at large scales.
Reply | Report Abuse | Link to thisI have to disagree with the idea that:
"There is enough food to go round now. There are many reasons people starve, but one of the most central is that the world's resources are not shared out fairly."
While it would be possible to better manage food usage to feed those incapable of raising there own food, I think the cold, hard facts are that doing so only increases birth & survival rates in areas that cannot produce adequate nutritional resources. As I understand, the continent of Africa's population has increased 58% during the past 20 years, while its food production is the lowest of any populated continent. These things are very difficult & complex, but feeding the starving children will produce more children to feed.
Island
Reply | Report Abuse | Link to thisYou perception that we are all living on one planet and should bee looking out for each other is your your personal view and culturally is a position that is not consistant with how society has operated historically. It may seem to make sense to you ethically from your perspective, but it is inconsistant with the way the world is actually being governed. It is governed by 200 independent nation states largely looking after their own long term interests.
Use of organic natural fertilisers is the answer. Chemical fertilisers besides harmful to environment will lessen the natural fertility of the soil.
Reply | Report Abuse | Link to thisDr.A.Jagadeesh Nellore(AP),India
E-mail: anumakonda.jagadeesh@gmail.com
The last paragraph encapsulates the flaw in the author's thinking. He seems to think that there is a fixed amount of fertilizer in the world and the rich countries are hogging it.
Reply | Report Abuse | Link to thisThe reality is more like the Jay Leno Doritos commercial, "Eat all you want. We'll make more." If Third World countries could afford more fertilizer, more fertilizer would be produced. If First World countries buy less fertilizer, some fertilizer producers will go out of business and less fertilizer will be produced.
If you want to see farmers in Third World countries producing more food, probably the fastest way to make that happen is for the US and EU to stop depressing food prices in those countries by dumping agricultural surpluses there. To some extent biofuels like ethanol and biodiesel are doing that now. For some reason, many people are not happy with the fact that Third World farmers are now earning enough money to buy more fertilizer to increase production.
You are wrong, Gilligan. There are limits to the amount of fertilizer that can be produced.
Reply | Report Abuse | Link to thisSome are limited geological deposits such as phosphates.
Nitrogen is one nutrient that is limited by the problems it creates (N2O is a potent greenhouse gas with about a 300 CO2 equivalence global warming potential). Not to mention the terrorist danger from easy access to Ammonium Nitrate.
Your post does not detract from the articles point about more EFFECTIVE use of the existing fertilizer production.
Still, the fact is the article is basically pointless since it ignore the FAR bigger issue of using fertilizer and even MORE critical irrigation water to feed automobiles. 40% of the USA corn crop along with enormous water & fertilizer is burned stupidly in automobiles. An avg of 980 gals of fresh water per gal of corn ethanol produced and 150 liters of fresh water consumed per km of avg vehicle travel on ethanol, or 600 liters per km for a biodiesel (soybean) fueled vehicle. By FAR-AND-AWAY the much more critical issue:
Reply | Report Abuse | Link to thiswww.biofuelwatch.org.uk/
Since the Haber-Bosch Process was invented during WW I, there has been no shortage of nitrate fertilizer. If you are that worried about ammonium nitrate there is the option of fertilizing with anhydrous ammonia.
Reply | Report Abuse | Link to thisWhile there is in theory some finite amount of phosphorous on earth, we are no where near running out. If it gets scarce enough we can extract phosphorous from sea water.