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Response to opinion piece on global population and food supply

Tue 17, Dec 2019


Dear Members,

Mike Foale raises issues that are on many minds within AIAS.  The impact of increasing population on food demand and the environmental impact of the larger agriculture needed to feed the world is now further complicated by the promised climate crisis.

The arithmetic of food demand and agricultural productivity is sound enough to make calculations of area required to feed a world of whatever population with current or potential yields. In 2009, FAO predicted a required food increase of 70% to better feed a projected population of 9.2 billion by 2050. The predicted population for 2050 has increased to 9.7 from a present (2019) 7.7 billion, and of course 10 years has passed.  A more recent analysis is based on actual staple food production and crop areas for the period 1961–2014 (Fischer and Connor, 2018). During that time, production (227%) has increased more than population (141%) so food has become more available and affordable.  Crop area has increased by 31% with half of that due to more intensive cropping of current area.  The conclusion for 2050 is not for disaster but for the enormous challenge that will be required to maintain crop yield increase of 1.1–1.3% pa required to provide affordable food with security while minimizing expansion onto new land.  Because world population growth is decreasing the challenge will be greatest in the next two decades.  Significant progress is essential in the next decade if food security is to be assured by 2050.  Mike draws attention to the two parts of the issue on the supply side of the problem.  Crops that are more productive and new farming systems that do better agriculturally and environmentally.  Here, I concentrate on those issues and leave other important sociological issues of population and food fashion to others.

On the former he draws attention to studies that aim to redesign crop plants. That work can continue and in the short-term concentrate, with more useful results, on resistance to current pest and disease problems rather than the much more difficult multigenic controls over yield.  But anyway, we do not have to wait for new plant designs for greater yield.  Yield gap analyses between farmers’ yields and what is possible by application of best cultivars and practices (Fischer et al., 2014) demonstrate current ability to provide the required additional production. The major requirements are for inputs to raise fertility and control weeds, pests and diseases.  Redesigned plants would not remove those requirements. Yield gains are more readily available where yields are small in developing countries, especially in Africa.  And that is where the hunger is. Therein lays an enormous sociological challenge.

Calls for a farming revolution are common in developed countries.  Analyses of various proposals for radical changes to agricultural practice reveal that farmers have already evaluated, or are evaluating, the proposed changes to climatic and economic circumstances (Connor and Mínguez, 2012).  A current Australian example is re-evaluation of the potential of intercrops to reduce inputs and control pests and diseases. The more efficient way to adapt farming to future conditions is to support farmers with the evolution of farming practice that is constantly underway, than to propose a revolution towards untested options.  Having said that, there is a need for massive change in those developing countries where many subsistence farmers hold land out of efficient production while growing urban populations depend on imported food aid.  Land that currently feeds 2–3 people per hectare could, when managed with available technology at an adequate scale, feed 10 or more.

Unfortunately, there is no clear way in which to discuss the pending climate crisis in terms of agriculture and food supply, except to say that unless there is real progress to increase food production before 2030, the world the food security problem will be compounded soon afterwards.  I am writing this on 2 December 2019 while the COP25 meeting is underway in Madrid. The broader concerns of climate change are seen to overwhelm all other problems and the immediate threat of world hunger is seemingly ignored.  The focus is on 2050.  The populace is being asked to believe that a temperature increase to 1.5ºC, achievable if the planet can achieve carbon neutrality by then, is manageable anything greater will spell disaster.  That presumably means it will be more expensive to solve.  At the same time, despite discussion and previous agreements for its reduction during recent decades, atmospheric [CO2] continues to increase.

Under a scenario like this, a defensible proposal for Mike’s discussion could concentrate on Australia’s agriculture and climate and seek to develop realistic scenarios away from the international doom and gloom that will continue to identify a villainous role for agriculture.  While world agriculture is a significant emitter of greenhouse gases (GHG, 11% of total IPCC 2004) the main sources are elsewhere and more generally distributed in society.  Perspective on society’s role in GHG production, relative to agriculture, is shown by the calculation that it takes more energy to toast a piece of bread that to produce the wheat that it contains.  For this reason, discussion about the future for agriculture in a decarbonizing world needs to involve the other actors in the food industry and the consumers that they seek to serve.

Discussion could focus on improvement of agricultural practices that can help Australian farmers meet the challenges of weather variability and climate change and remain a major contributor to national GDP.  A new publication can provide much valuable information and analysis of modern trends in Australian agriculture (Pratley and Kirkegaard, 2019). There is a good basis on which to build this vision following work by agronomists, climate scientists and crop modellers.  A good example is the Yield Prophet project (Hochman et al., 2009; Hochman et al., 2012) that uses data and simulation to assist decision making, in this case N application to wheat. The general objective, that is enormously wide, will be to develop practices that improve efficiency of resource use in the face of more variable weather and uncertain climate trends.  For this, weather forecasts need to be more accurate for longer periods and climate change predictions need to be more spatially accurate.  And perhaps the time has come for more field studies, the re-opening of agricultural experiment stations that have largely disappeared during the last half century and a re-launch of installations such as FACE-Horsham.

A serious application of climate science to agriculture and the food industry can seek answers to basic questions. To what extent can productive agriculture be decoupled from CO2 emission? What possibility exists for productive agriculture to become the CO2 sink for society’s emissions?


David Connor FAIA (

Emeritus Professor of Agronomy

The University of Melbourne


Connor, D.J., Mínguez, M.I., 2012. Evolution not revolution of farming systems will best feed and green the world. Global Food Security 1, 106-113.

Fischer, R.A., Connor, D.J., 2018. Issues for cropping and agricultural science in the next 20 years. Field Crops Research 222, 121-142.

Fischer, T., Byerlee, D., Edmeades, G., 2014. Crop yields and global food security: will yield increase continue to feed the world. ACIAR, Canberra.

Hochman, Z., Gobbett, D., Holzworth, D., McClelland, T., van Rees, H., Marinoni, O., Garcia, J.N., Horan, H., 2012. Quantifying yield gaps in rainfed cropping systems: A case study of wheat in Australia. Field Crops Research 136, 85-96.

Hochman, Z., van Rees, H., Carberry, P.S., Hunt, J.R., McCown, R.L., Gartmann, A., Holzworth, D., van Rees, S., Dalgliesh, N.P., Long, W., Peake, A.S., Poulton, P.L., McClelland, T., 2009. Re-inventing model-based decision support with Australian dryland farmers. 4.  Yield Prophet® helps farmers monitor and manage crops in a variable climate. Crop and Pasture Science 60, 1057–1070.

Pratley, J. and J Kirkegaard (Eds.) (2019). Australian Agriculture in 2020: From Conservation to Automation. Agronomy Australia and Charles Sturt University: Wagga Wagga.


Note: free access to ”Australian Agriculture in 2020” ( Pratley and Kirkegaard 2019), an excellent and up-to-date view of the subject:     

Note: free access to “Crop yields and global food security” (Fischer et al 2014), a comprehensive study of this issue:



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