Tuesday, 20 April 2010

The future of agriculture

The future of agriculture

Throughout the history of humanity, famine has been an ever present danger, bringing entire civilisations to the brink of destruction. Despite centuries of agricultural advancement, around 923 million people still face malnourishment today [1]. Even for those who survive, the deprivation of nutrients, particularly in childhood, can result in lifelong disadvantage that makes it all but impossible to escape the poverty cycle [2].

This tragedy shows no signs of abating. Every day, the earth's population expands alarmingly. By 2050, there may be as many as 9.2 billion people on the planet [3]. This dramatic increase in demand for food will place enormous strain on the global agricultural production system. Compounding on this surge in demand is the fact that it is becoming difficult even to hold the supply of food at current levels. Arable land worldwide is becoming scarcer [4] due to factors such as the encroachment of cities on farming land [5] and unsustainable farming practices which lead to topsoil losses [6]. In addition, plant diseases and infestations are on the rise, forcing plant breeders to engage in desperate battles to prevent crops from being decimated [7]. Most tellingly, the ability to wring productivity gains from the introduction of modern farming practices is declining as the benefits of fertilisers and pesticides reach a plateau [8]

On its present trajectory, the global food supply network cannot continue to provide adequate nourishment for the world's population. Radical changes are needed to revitalise agriculture by improving the crop yields on existing land and by reversing the trend towards aridity.

These changes will not be simple and will require the co-operation of workers from many disciplines including land management; biotechnology; engineering; finance; and government. Cutting through their disparate disciplines will be a shared quality of entrepreneurship: bright minds with an ability to see opportunities to reform the existing system as well as a burning desire to enact social change. These people will be the leaders of tomorrow.

The green revolution

The inability of the earth's farming system to adequately cope with a rapidly growing population is not unprecedented. In the early twentieth century, a similar situation was occurring. The world's rapidly accelerating population levels saw farmers and agricultural scientists alike scrambling for ways to prevent the granaries from running empty. Fortunately, a combination of measures was developed and implemented, which dramatically boosted crop yields. Technologies including farm mechanisation, chemical fertilisers, pesticides and crop irrigation were used in tandem to allow farmers to tend to much greater areas of land [9].

Initially, these improvements were restricted to developed nations who could afford the large capital outlay for tractors and drums of fertiliser. However, in 1945, a forward thinking, American agronomist named Norman Borlaug, backed by the Rockefeller trust, sought to bring modern agricultural practices to the third world. His breakthrough was to use more productive varieties of maize, wheat and rice, which had been bred by agricultural scientists to absorb more Nitrogen from the soil [9]. When supplied with fertilisers, these plants performed substantially better than previous cultivars. Mexico, India and Pakistan soon benefited; going from countries under constant threat of famine to being net exporters of some crops. As a measure of the success of what became known as the 'Green Revolution', global cereal yields doubled between 1961 and 1985 [10]. Most food security analysts agree that without the introduction of Green Revolution farming practices, famine would have exacted an enormous death toll, particularly in poorer countries [11].

Criticisms of the Green Revolution

However, despite the enormous benefits that the Green Revolution has brought, it has not been a panacea for agriculture's woes. While philanthropic institutions such as the Rockefeller trust did bring modern agricultural practices to many third world countries, African countries have largely missed out [11]. A key reason for this is the fact that the Green Revolution has resulted in farmers becoming dependent on agribusiness corporations to supply them with fertilisers and pesticides that many small subsistence farmers still cannot afford [11].

Additionally, the introduction of high yielding varieties has led to the transition towards monocultural farming, wherein one type of crop is grown exclusively. Monocultures come with the detrimental side effect of reduced food security due to a vulnerability to pests and diseases. Emergent plant viruses can quickly decimate the crops of entire countries as was seen during the Irish potato famine in 1845 [12].

Environmental damage is another major downside of the Green Revolution. There is evidence that the nitrogen in fertilisers can react to form Nitrous oxide, a potent greenhouse gas, which is a key player in anthropogenic climate change [13]. Crucially, the Green Revolution has also been linked to land degradation due to unsustainable farming practices that cause the loss of topsoil and consequently, useful farmland [6].

Further adding to the loss of arable land, cities are beginning to encroach on what was previously prime farmland [5]. The expansion of the world's population now overwhelmingly occurs in cities [3], which usually sprawl outwards to make room [14].

These dual pressures of population growth and scarcity of arable land will eventually mean that even with the high yielding cultivars developed by modern plant breeders, there will come a point where there are simply too many mouths for the current system to feed.

Improving crop yields through biotechnology: the second Green Revolution

In recent decades, a revolutionary, new field of science has emerged which has the potential to carry on from where the first Green Revolution left off. Modern biotechnology sprung into existence just thirty years ago with the advent of techniques to modify the genetic blueprint of organisms [15]. Since then it has exploded into an industry worth around $917 billion per year [16] and has led to profound advancements in the treatment of human disease as well as in novel varieties of plants, which are bestowed with properties that make them attractive for farmers to grow. The ability to generate superior plant cultivars using biotechnology is so powerful that the movement has been lauded as the second Green Revolution [17].

The key promise of agricultural biotechnology is the ability to mix and match genes from different organisms or to alter genes within plants that traditional plant breeding would never be able to access. The area of cropland planted with GM species has increased exponentially in recent years, rising from 1.7 million hectares in 1996 to 114.3 million hectares in 2008 [18].

Currently there are a number of Genetically Modified (GM) crops on the market, which are resistant to broad spectrum pesticides such as Glyphosate [19]. This allows farmers to more easily eradicate weeds, reducing labour costs and improving crop yields due to reduced competition for resources from non crop plants [20]. Scientists have also developed species, which do not require any pesticides to be sprayed whatsoever. By implanting 'BT' genes, plants can be designed to express 'cry toxins', which are deadly to specific pest insects, but harmless to humans and other non target organisms [21].

The vagaries of climate variability could also be avoided through the insertion of frost and drought tolerance genes. Both drought and frost cause billions of dollars in lost agricultural production each year [22]. GM crops are being developed which accumulate 'anti-freeze' molecules within their plant cells, rendering them much less vulnerable to the water stress sustained during drought and frost events [23].

Furthermore, plant biotechnology has the capacity to generate crops which could dramatically reduce the global incidence of malnutrition. For instance, the nutritive value of staple cereal crops such as rice can be improved by the addition of genes for the production of Vitamin A. Vitamin A deficiency leads to blindness in hundreds of thousands of children each year, mainly in Africa and south east Asia [24]. Biotechnologists have developed 'Golden rice', which expresses a yellow Vitamin-A derivative [25]. 'Golden rice' offers an inexpensive and effective solution to the widespread problem of Vitamin-A deficiency and will soon be distributed under free humanitarian licences to farmers around the world [26].

A particularly exciting area of research is the re-engineering of critical parts of the metabolic machinery of plants to make them more efficient. Most plants cultivated by humans use an enzyme called Rubisco to take up carbon dioxide from the atmosphere to be incorporated as sugar molecules in plant tissue. This enzyme is notoriously inefficient and up to 30% of biomass production is lost due to Rubisco's tendency to mistakenly accept oxygen instead of carbon dioxide [27]. Scientists around the world are working on methods to improve Rubisco by removing its affinity for oxygen and boosting its overall efficiency. This could result in versions of important crops such as wheat and soy, which could grow many times faster than even the best high yielding varieties developed during the first Green revolution [28].

Taken together, these improvements would allow farmers to supply humanity with a higher quality, more secure food supply in sufficient quantities to meet growing demand. However, in order for the ground breaking lab work performed by biotechnology researchers to be transplanted into the field, innovative and forward thinking farmers must come to the fore. Switching to these new generation crops will require tremendous courage, as the nature of the modern supply chain means that so much investment goes into each cropping cycle that one bad harvest can spell financial ruin for the unlucky farmer [29]. For the brave souls who are prepared to embrace the products of the second green revolution, the enormous productivity gains on offer could deliver large profits, while also improving social equity by reducing the prevalence of malnutrition in third world countries. Carrying on from the work of Norman Burlag during the first Green Revolution, these farmers and scientists carry the beacon of hope for agriculture.

Obstacles to the second green revolution

Despite the myriad benefits of GM crops, there are still many obstacles to their widespread adoption. Community opposition to GM crops is currently quite high primarily due to fears that GM crops could represent a health risk [30]. These fears are warranted, as GM techniques can result in the production of proteins or compounds to which the human body has never before been exposed [31]. For this reason, strict regulatory frameworks are necessary to ensure that proper testing of new GM crops proceeds before they are released into the environment. However, the balance between the need for regulation and the tremendous benefits that GM crops offer must be attended carefully.

Currently the regulatory regime in many areas, particularly in the European union, is so intensive and decision making so protracted that it can take decades for GM crops to receive approval [32]. It will take entrepreneurial leaders to slice through the red tape to allow the benefits of the second Green Revolution to flow through, while still ensuring the safety of the community.

Even if GM regulation were scaled back to reasonable levels and community opposition overcome, the fundamental question arises of whether biotechnology alone is enough to ensure the food security of planet earth. While the second Green Revolution addresses one side of the problem: agricultural productivity, it can do little about the seemingly inexorable decline in the extent of arable land. For this reason, I propose a new direction for agriculture: greening the deserts.

Greening the deserts

The Sahara has not always been a dry, desolate place. As late as 5000 years ago, the Sahara was home to lush savannah vegetation driven by monsoonal rain [33]. The earth's climate is quite different now, however, with modern technology, it may be possible to return the Sahara, and other desertified or marginal rainfall areas, to their former glory and in the process, open up millions of square kilometres of valuable cropland.

For such an attempt to succeed would require water in vast amounts. Fortunately, an ample supply is available: the sea. As exemplified in Israel, desalination plants can supply drip irrigation feeds, which allow farmers to grow high quality produce on otherwise arid patches of land [34]. These plants are very energy intensive, however, and in Israel, are fueled by oil with large commensurate CO2e emissions [35].

A far more sustainable method of desert regreening would involve harnessing the sun to power the requisite desalination plants. Solar thermal plants with vast arrays of mirrors that can concentrate the sun's rays one thousand-fold could soon allow electricity to be generated at very low cost through the kinetic energy of superheated steam [36]. At the same time, the evaporated water is liberated from its salt content and can then be condensed to deliver an ample supply of fresh water without the release of greenhouse gases.

Once a dependable supply of water to desert regions were in place, highly productive and drought tolerant GM crops could be grown, massively incrementing the global food supply. Most importantly, these crops would be grown in the areas which typically experience frequent food shortages. Furthermore, the strategy could help to mitigate against climate change as the supply of water would allow GM tree species with enhanced CO2 sequestration rates to be planted, lowering atmospheric CO2 concentrations.

The new leaders

Arguably, the biggest hurdle to the realisation of such a desert regreening strategy would not be technological, but rather psychological. For such a plan to succeed, it would require leadership from scientists; engineers; farmers; and most importantly investors. These actors would recognise the immense potential gains; evaluate the risks rationally, yet optimistically; and work together to deliver a solution that could secure the future of the earth's food supply. Given the examples set by the tireless work of people such as Norman Burlag, there is every reason to suspect that ingenious solutions to agriculture's problems will emerge, created jointly by pioneers from many different disciplines.


[1] UN Food and Agriculture Organisation, The State of Food Insecurity in the World 2008, 2008.

[2] D. Almond, L. Edlund, H. Li, and J. Zhang, Long-term effects of the 1959-1961 China famine: Mainland China and Hong Kong, NBER, 2007.

[3] UN Department of Economic and Social Affairs, Population Division, “World Population Prospects: The 2008 Revision,” 2009.

[4] Food and Agriculture Organization of the United Nations, Summary of World Food and Agricultural Statistics 2009, 2009.

[5] M. Tan, X. Li, H. Xie, and C. Lu, “Urban land expansion and arable land loss in China—a case study of Beijing–Tianjin–Hebei region,” Land Use Policy, vol. 22, 2005, pp. 187–196.

[6] D.R. Montgomery, Dirt, University of California Press, 2008.

[7] R.N. Strange and P.R. Scott, “Plant disease: A threat to global food security,” 2005.

[8] R. Yadav, D. Yadav, R. Singh, and A. Kumar, “Long term effects of inorganic fertilizer inputs on crop productivity in a rice-wheat cropping system,” Nutrient Cycling in Agroecosystems, vol. 51, Jul. 1998, pp. 193-200.

[9] K. Griffin, The political economy of agrarian change: An essay on the green revolution, Macmillan London, 1974.

[10] Conway G, The Doubly Green Revolution: Food for All in the Twenty-First Century., New York: Cornstock Publishing Associates, 1997.

[11] R.E. Evenson and D. Gollin, “Assessing the impact of the Green Revolution, 1960 to 2000,” Science, vol. 300, 2003, p. 758.

[12] D. Nardo and B. McGovern, The Irish Potato Famine, Lucent Books, 1990.

[13] F. IPCC, “Working Group 1 Report ‘The Physical Science Basis’,” Historical Overview of Climate Change Science, 2007, p. 105.

[14] E.L. Glaeser, M.E. Kahn, and L. Center, “Sprawl and urban growth.”

[15] J.E. Smith, Biotechnology, Cambridge University Press, 2004.

[16] D. Neyland, “Turkey a no-show at BIO, expo for $917 billion biotech sector,” Today's Zaman, 2009.

[17] G.B. Marini-Bettòlo, A.N.D.S.D.D. XL, C.O.T.E. Communities, and E.(.:. Italy), Towards a second green revolution, Elsevier, 1987.

[18] C. James, “Global Status of Commercialized Biotech/GM Crops: 2008, International Service for the Acquisition of Agri-biotech Applications,” ISAAA Briefs, vol. 39, 2008.

[19] D.M. Stalker, W.R. Hiatt, and L. Comai, “A single amino acid substitution in the enzyme 5-enolpyruvylshikimate-3-phosphate synthase confers resistance to the herbicide glyphosate,” Journal of Biological Chemistry, vol. 260, 1985, p. 4724.

[20] T.J. Monaco, S.C. Weller, and F.M. Ashton, Weed science, John Wiley and Sons, 2002.

[21] A.M. Shelton, J.D. Tang, R.T. Roush, T.D. Metz, and E.D. Earle, “Field tests on managing resistance to Bt-engineered plants,” Nature Biotechnology, vol. 18, 2000, pp. 339–342.

[22] National Oceanic and Atmospheric Administration, Summary of Natural Hazard Statistics for 2008 in the United States, NOAA, 2008.

[23] T. Umezawa, M. Fujita, Y. Fujita, K. Yamaguchi-Shinozaki, and K. Shinozaki, “Engineering drought tolerance in plants: discovering and tailoring genes to unlock the future,” Current Opinion in Biotechnology, vol. 17, Apr. 2006, pp. 113-122.

[24] K.P. West Jr and S. Mehra, “Vitamin A intake and status in populations facing economic stress,” Journal of Nutrition, vol. 140, 2010, p. 201S.

[25] J.A. Paine, C.A. Shipton, S. Chaggar, R.M. Howells, M.J. Kennedy, G. Vernon, S.Y. Wright, E. Hinchliffe, J.L. Adams, A.L. Silverstone, and others, “Improving the nutritional value of Golden Rice through increased pro-vitamin A content,” Nature biotechnology, vol. 23, 2005, pp. 482–487.

[26] International Rice Research Institute, Golden Rice Fact Sheet, IRRI, 2005.

[27] F.R. Tabita, “Rubisco: The Enzyme that Keeps on Giving,” Cell, vol. 129, 2007, pp. 1039–1040.

[28] M.A.J. Parry, P.J. Madgwick, J.F.C. Carvalho, and P.J. Andralojc, “Prospects for increasing photosynthesis by overcoming the limitations of Rubisco,” JOURNAL OF AGRICULTURAL SCIENCE-CAMBRIDGE-, vol. 145, 2007, p. 31.

[29] R.S. Hails, “Assessing the risks associated with new agricultural practices,” Nature, vol. 418, 2002, pp. 685–688.

[30] N. Williams, “The growing GM challenge,” Current Biology, vol. 19, 2009, pp. 268–269.

[31] K. Ramessar, T. Capell, R.M. Twyman, H. Quemada, and P. Christou, “Calling the tunes on transgenic crops: the case for regulatory harmony,” Molecular Breeding, vol. 23, 2009, pp. 99–112.

[32] M. Qaim, “The Economics of Genetically Modified Crops,” 2009.

[33] S. Kröpelin, “Lakes in the Sahara,” German Research, vol. 31, 2009, pp. 4-9.

[34] S. Ramanathan, “Greening the Desert the Israeli Way: Is It Good Economics?,” Economic and Political Weekly, vol. 29, Feb. 1994, pp. 476-477.

[35] R. Sanders, “Water desalting and the Middle East peace process,” Technology in Society, vol. 31, Feb. 2009, pp. 94-99.

[36] A. Al-Karaghouli, D. Renne, and L. Kazmerski, “Solar and wind opportunities for water desalination in the Arab regions,” Renewable and sustainable energy reviews, 2009.

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