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As highlighted at our Strategy briefing on 22 May 2019, one of the strategic themes expected to shape our long run operating environment is the need to become more effective stewards of the biosphere.

Here we investigate a very important question within that broader theme.

For most of settled human history, our species lived a precarious existence from one harvest to the next.

That changed with the “Green Revolution” of the 1960s, which saw the massive, predominantly aid-financed, implementation of advanced agricultural practices (e.g. mechanisation, irrigation, chemical fertiliser application, and use of high-yielding and pest-and-rust-resistant seeds) in the developing world. Its result was a spectacular boost in agricultural productivity over the ensuing decades – a boost that helped improved everyday life immeasurably for billions of people across East Asia1, Central and South America, South Asia and Africa.

The daily supply of calories per person has increased 34% in Mexico, 30% in South America and around 23% and 30% in India and Africa respectively. In China, it has more than doubled, albeit from a lower base2.The Engel coefficients of developing countries – the proportion of household income that is spent on food – have been in steady decline in recent decades as a result3. And yet, addressing an audience at the Food & Agriculture Organization of the United Nations (FAO) in April of 2019, Cornell professor Chris Barrett sounded the alarm bell on food security. He labelled it “the defining global challenge of the century”4.

But according to the USDA’s International Food Security Assessment (IFSA), while food insecurity is far from resolved, its incidence is declining: the proportion of people identified as food insecure in its sample of at-risk countries has fallen from 29% to 21% since 2000 and is projected to be just 10% by 20285. So, why does Barrett believe that “the prospect of failing to meet the food security challenge is nothing short of an existential crisis?”

Food security refers to people’s physical, social and economic access to sufficient, safe and nutritious food that meets their food preferences and dietary needs for an active and healthy life6. The three pillars of food security then are:

1. the ability to produce enough of the desired food;
2. the provision of appropriate infrastructure to distribute and store that food, and
3. its affordability to the consumer.

Lifting people out of poverty through effective development policies that assist participation in global supply chains, investing in logistics infrastructure and resolving conflicting zones can all contribute to improved food security.

Today, access constraints drives much of the food insecurity that is presently identified. Lifting people out of poverty through effective development policies that assist participation in global supply chains, investing in logistics infrastructure and resolving conflicting zones can all contribute to improved food security. But population growth and dietary change continue to drive up food demand – the FAO projects an approximate 50% increase in demand for crops between 2013 and 20507 – so it is vital that global agriculture is able to keep pace, and it is here that Barrett warns that “land, water and marine resources are growing more limited”, urging policymakers to accelerate agricultural adaptation to climate change, water scarcity and soil health.

When it comes to growing the crops that go into our foods – as fresh produce, components of processed foods and feed for animals – there are really only three options available to meet the FAO’s projections. Either we drastically reduce food wastage, thus meeting higher food demand without a proportionate increase in crop production, or we turn more land over to agriculture (with associated negative impacts on bio-diversity if not well managed), or we grow more on the land we have through increased productivity.

Food loss and waste is a huge challenge for society.

Food loss and waste is a huge challenge for society. It comes in many forms – from food damaged by pests or moulds, to supply chains losses due to lack of mobile cold storage or more basic distributional short-falls, to quality control by supermarkets - or just those forgotten jars at the back of the fridge.

Many of these types of losses tend to increase with people’s incomes – as we get wealthier, we become less price sensitive and more likely to throw out surplus or soon-to-expire food, and we purchase a wider range of foods, particularly perishable items like meat, fruit and dairy products. And to meet these demands, the food supply chain is extended, with more processing and more international trade, while stricter controls are placed on safety, aesthetic appeal and standard sizing – often creating more waste.

Some of the most profligate food consumers – like the US and the EU – are making some attempts to reduce and recycle, and some interesting progress has been observed in import-dependent, wealthy North Asian countries. On the other hand, fast growing populous nations like India and China are likely to see consumer-level waste worsen in coming decades as incomes, and diets, improve8. The surety that we will see rapid change in these giants dramatically raises the stakes.

Since 2000, crop production has risen by nearly 50%, but we estimate that cultivated land has expanded by less than 3%.

So, let’s turn to crop production and how to boost it. The UN estimates that about 12 per cent of the world’s ice-free land area is used in crop production9. So while land that can support agriculture may not be scarce in absolute terms, problems such as deforestation and associated biodiversity and bio-sequestration loss, water availability, erosion and poor quality soils often make expansion undesirable or infeasible or in certain cases, indefensible. Indeed, the UN estimates that land degradation has reduced the productivity of almost one-quarter of the Earth’s land surface10. Since 2000, crop production has risen by nearly 50%, but we estimate that cultivated land has expanded by less than 3%.

Given these constraints on land supply, the emphasis is placed squarely on achieving higher and higher crop yields from the area we are presently cultivating. In 2000, the global average yield per hectare of corn was under 4.5 tonnes. Today it is nearly 6 tonnes11. But can we keep making those kind of gains, especially in the context of the headwind provided by land degradation from unsustainable practices in the past? The answer is crucial to future food security.

Breaking the problem down once again, there are two ways of achieving better crop yields.

The first is to develop cultivars that have a higher yield potential than existing varieties – that is, the maximum yield that can be achieved in a suitable environment with sufficient provision of sunlight, heat, carbon dioxide, nutrients and water, and control of disease, pests and other stresses. The main areas of research here are ‘dwarfing’ (reducing the size of the non-harvested parts of the plant), tolerance of high-density planting, and efficiency of photosynthesis. Some in the scientific community are sceptical how much more can be achieved through crop genetics12, although we are conscious that if the principles of artificial intelligence are fully brought to bear on this critical problem, steady progress might well be made13.

The second route is to close the gap between potential yields and actual yields. There are many environmental factors that can limit yields, including adverse weather conditions, nutrient deficiency and biotic stressors (pests, diseases, weeds). Even in advanced economies like the United States, the yield gap is substantial – estimated at 22% for maize, for example – but in many parts of the world, the gap is far larger. For India’s 100 million tonne rice crop, it’s more than 50%14.

New cultivars can play a role here too, by improving drought tolerance or disease resistance – both mitigations against climate change impacts. But provision of the nutrients essential to plant growth, in adequate quantities, is also vital. The three ‘primary’ nutrients most commonly applied are nitrogen (in the form of urea or nitrates), phosphorus (in the form of phosphates) and potassium.

The “4R principles” encourage farmers to seek advice so that they can choose the right fertiliser to deliver the necessary nutrients, apply it at the right rate, at the right time and in the right place.

Which brings us to potash. We estimate that potash typically accounts for less than 10% of farmers’ input costs on average (noting wide variability by specific crop and region) and only a tiny fraction of retail food prices. So, it is not a burden on food security from the perspective of affordability. However, getting its application right is invaluable in sustainably supporting the yield growth that the world needs.

Potassium is an essential ‘building block’ for plants, playing roles in water regulation, protein synthesis and enzyme activation. The provision of adequate potassium can contribute to higher yields by improving resistance to stress (including drought) and enhancing uptake of another essential nutrient, nitrogen. The more food (and non-food) crops the world needs to grow, the more potassium will be required to ‘build’ those crops and maintain and increase their quality. Whether the extra crop production comes from a move to cultivate less fertile soils, or via higher yields on existing land, or a combination of the two, we expect potash application rates to continue their upward trend in order to maintain the health of our soils.


Potash is nothing more, or less, than a vital link in the delicate chain from which our food security hangs.

A determined, world-wide shift towards a scientifically sustainable agriculture is required if we are to provide for the projected appetites of 10 billion global citizens in 2050.

1 In East Asia, this accommodated a major shift in the labour force towards manufacturing and services employment in urban centres. We highlight here the link between agricultural productivity and the virtuous circles of economic development in labour-rich economies in the Indian context.
2 China is a special case, as it was still recovering from the disastrous impacts on agriculture of the Great Leap Forward at the starting point of this period. Further, the impact of the Household Responsibility System in the early 1980s was an independent event that had profound implications for agricultural productivity in the world’s most populous country. 
3 Data in this paragraph sourced from and
4 The webcast of Barrett’s speech, (The George McGovern Lecture) is available here:
7 The FAO projection is within BHP’s low-high range.
8 Rising urbanisation is also tightly correlated with increased consumption of take-away and packaged, rather than fresh foods, which creates a rise in non-food waste, often plastics.
9 IPBES data cited at Note that further 25% of ice-free land is used for the grazing of livestock.
13 AI is also making some inroads to food waste reduction in the hospitality sector, a trend we are watching with interest. See for instance
15 The Nitrogen and Phosphorus cycles have been isolated as critical planetary boundary conditions. See Steffen et all (2015) in Science Potash run-off is not a recognised cause of eutrophication.

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