drone image of a farm with exposed soil

Soil Degradation and Global Hunger—4 graphs that should scare the pants off you

Despite plenty of food, a global surge in hunger, malnutrition, and population trends all circle back to soil degradation.

Soil degradation is where the soil is depleted in organic matter, nutrients, and structure to levels that reduce biomass production under average climate and management conditions—a fancy way of saying that depleted soils grow less food.

The statistic I am about to share should scare the pants off you…

 At least a fifth of global soil is degraded. 

When the human population is the highest it has ever been—more than three times the number of people to feed than were alive in 1950—and at least half of these people can access nutrient-rich food, the soil that grows the food is failing.

Degraded soils produce fewer crops and livestock than their potential, but at the extremes, deterioration means the loss of topsoil altogether from erosion by wind and water. Various scientifically robust estimates have soil erosion rates an order of magnitude higher than that of natural erosion or soil formation processes.

The soil degradation problem is already acute enough for farmers to leave the land. Many fields are abandoned each year because the soil is exhausted of nutrients.

The evidence suggests agricultural land abandonment is widespread globally, driven by multiple factors, and has strong implications for biodiversity, ecosystem services and human well-being

Prishchepov, A. V., Schierhorn, F., & Löw, F. (2021). Unravelling the Diversity of Trajectories and Drivers of Global Agricultural Land Abandonment. Land 2021, 10, 97.

The scary statistic of soil degradation in a fifth of global soils means that one in every 5 acres of land used for agriculture across the globe is not performing as well as it could because the soil is depleted from overuse or poor management.

I’m guessing you didn’t know any of this.

Most Western consumers are blissfully unaware of soil because of what they see at the store and this headline. 

There is plenty of food.

In mature economies, supermarkets are full of a glittering array of foods irrespective of the season, and access is more a matter of social disadvantage than supply.

Indeed the global north appears to have a problem of too much food, has an obesity epidemic. 

One in three Americans, one in four Brits and at least 10% of just about every citizen in mature economies have a body mass index (BMI) over 30, the metric and threshold the World Health Organisation uses to define the abnormal or excessive fat accumulation that presents a health risk. 

WHO estimates that more people are obese than underweight in every region except sub-Saharan Africa and Asia.

So here is scary graph #1

Graph showing the percentage of the total population with a BMI >30. The highest is 30.6% in the United States

Graph created by TastyCakes – PNG Version on English Wikipedia, original by Phils., CC BY 3.0

An increasing and significant proportion of adults in the west are overweight or obese. 

The implication is that in many regions of the world the six-continent global food supply chain delivers more than enough food or perhaps the wrong food. 

Although famine killed nearly 75 million people in the 20th century, it virtually disappeared in recent decades. The Famine Early Warning Systems Network created by USAID in 1985, is a leading provider of early warning and analysis on food insecurity has parts of Ethiopia, South Sudan, Yemen and Nigeria on emergency level of acute food insecurity, but no areas in famine.

Fewer food disasters on the news reinforce the perception of plenty of food. 

But then there is this headline.

Hunger is rising.

Famine might be down, but hunger levels are alarming, with 1 in 10 people on Earth, an estimated 768 million global citizens, undernourished in 2020

Then the COVID-19 pandemic hit.

United Nations data suggest hunger increased by 118 million people from 2019 when 8.4% of the world’s population was undernourished. Impacts of the COVID pandemic on hunger include food supply shortages, malnourishment due to supply chain disruption, labour shortages due to illness and a global rise in food prices. These effects will persist for years and have the most significant impact on people experiencing poverty.

Here is scary graph #2.

Graph showing the number of undernourished people in the world from 2000 to 2020 with an alarming spike since 2019

Adding twice the UK population to the hungry in a year means many people were on the edge of hunger. What looked like progress in reducing the number of undernourished people worldwide is reversed in a single disruption.

As a consequence of our evolution as wandering foragers, we are adapted to persist for a long time, even when our basic level of nutrition is unmet. Humans are an exceptional species at survival on modest food sources. The speed of this rise in undernourished people is alarming, given that hunger is the expression of acute food shortages. 

There is not enough food where it is needed, and its getting worse.

At the sharp end of malnutrition the World Food Program estimates that in 2023 more than 345 million people facing high levels of food insecurity, more than double the number in 2020. The uptick in the scary graph #2 continues.

Then there is the demand from ever more people.

Watch the trends in population.

Genetic and anthropological evidence suggests that Homo sapiens have been a species for 300,000 years after separating from our Hominid ancestors. 

Before the invention of agriculture 12,000 years ago, the total number of humans that had ever lived was 9 billion. That is the sum of all the humans who walked the earth for 288,000 years. Since the invention of agriculture, 92 billion people have lived and died.  

In 2023, the human population stands at 8 billion or 7% of the humans that have ever been.

Take your hat off to us. Not only have modern humans persisted, but we are also genius level at making more of everything, including more people. And this ability has accelerated dramatically since the 1950s.

When I was born in 1961, 3 billion people were going about their business of making more. In my lifetime, 4.5% of the humans who have ever lived were born and survived to 2023. 

This is truly amazing and also scary.

Since the 1980s, the absolute number of people added to the global population each year has been around 80 million souls—each year we add the population equivalent of one Germany or three Australia’s to the worldwide population.

Rather than present the typical hockey stick graph of human population growth that shows our numbers trickling along until the industrial revolution sent them skyward here is another way to visualise population growth.

Scary graph #3

Absolute increase in the number of people on earth each year. It is currently over 80 million even as soil degradation expands

The addition of 800 million new people in a decade is a huge extra demand on food supply on a daily 22 trillion kilocalories challenge for energy needs. Then there is nutrition to maintain metabolic health. As the saying goes, man cannot live on bread alone.

The food supply is enough now, but can it cope with feeding another Germany every year?

Access to enough food is an acute problem for the hundreds of millions of global citizens who are food insecure. Failure to access the suitable types of food is a problem for an increasing proportion of people in every country.

Soon enough, the balance of people food insecure will reach levels that cause social instability at best and collapse at worse.

And so we are back to the soil degradation problem because almost all food production comes from plants grown in soil—we grow our food.

Agriculture changed the game. We could decouple our numbers from the constraints of a foraging animal and increase our numbers on the energy excess from crops we grew in fields and livestock we herded across grasslands.

Then everything changed.

Fossils arrived and turned agriculture from an energy source to an energy sink. We used the power of coal, oil and gas to drive machinery on farms and make fertilisers, herbicides and pesticides in factories to intensify agriculture. Now we could grow more food than we could eat. 

And here we come to scary graph #4

Graph of wheat yields by country from 1960 to 2018

At first glance, this doesn’t look scary at all. Graphs showing a trend from bottom left to top right are good. 

In this one aggregate wheat yield is going up, reflecting a global trend since the 1960s for greater agricultural production across most commodities.

But take a closer look at the last 30 years. Here is the graph that zooms in on that period.

Graph of wheat yields by country from 1990 to 2018 showing that growth in yield has stalled.

Note that this is a random subset of countries, and Our World in Data has an interactive graph for wheat yield where you can select countries to see the trend from 1961. 

Some countries are still achieving yield gains, but modest yields have plateaued in several including the UK, US, Nigeria and Angola. 

But the human population continues to grow at 80 million per year throughout this period.

If crop yield has or is about to reach a maximum under the existing technologies for soil management but there are more mouths to feed, then more land will be needed to grow the food.

Turns out that land use change continues but is hard to pin down.

Expansion in global cropland (1 million km²) and pasture/rangeland (0.9 million km²) adds agricultural land to the production system, typically at the expense of forest, but there is also agricultural land abandonment in Europe and the United States, climate-induced vegetation shifts in Siberia, and woody encroachment of rangelands in the United States and Australia.

These global land-use changes suggest that agricultural production needs more land to meet demand even as some of the once productive land is abandoned or is degraded.

We do know that human land use is the reason for biodiversity loss and that if we keep cutting down forests to grow food, we increase greenhouse gas emissions and make it impossible to tackle both problems with rewilding.

But here is the scary part.

If a fifth of global agricultural soil is underperforming due to soil degradation, maintaining crop yields becomes much harder.

Takeaways from the 4 scary graphs

At least half the people in the world are malnourished because there is not enough food for some and too much of the wrong food for others.

The number of people in both categories can rise sharply. 

Despite the challenges of malnutrition, the global population continues to grow at over 80 million people per year—152 per minute.

In many places, grain yields have plateaued, and soil degradation is starting to impact the food supply.

These trends do not go together well.

What sustainably FED suggests

It’s a thrill ride. So what, the supermarkets are full.

Adrenaline seekers love these high stakes games of risk and reward. There is opportunity everywhere in a world on the brink of regional and even global famines. Heck, when food prices rise some people will make a dollar.

But this neoliberal mindset only applies to the billion or so people on earth who can afford to take a holiday overseas. 

The last thing these folks know about is soil degradation that just raised the stakes.

As the late and truly great Hans Rosling so entertainingly explained in 2010, there are two billion global poor, people who aspire to a pair of shoes and maybe one day a bicycle. And we are locked into that number growing to 4 billion by 2050 even if the miracle of economic growth continues.

Hans Rosling gives his epic TED talk that explains the what and why of global population growth from 1960 to 2050

It is the poor who suffer from this global brinkmanship. They cannot afford for the prices of food to rise or for supplies of cheap food to run low.

The supermarkets are full only for a few lucky folks.

Luck makes us blind to the source of that food, the medium that delivers sustenance to us all, rich or poor. Humanity will need every acre of fertile soil to stay fertile or those billions will starve. And before they do, in their desperation, they will raid the supermarkets. 

Think about it. 

Science source
Winkler, K., Fuchs, R., Rounsevell, M., & Herold, M. (2021). Global land use changes are four times greater than previously estimated. Nature communications, 12(1), 1-10.

Hero image modified from photo by Sandor Fehervari on Unsplash


Mark is an ecology nerd who was cursed with an entrepreneurial gene and a big picture view making him a rare beast, uncomfortable in the ivory towers and the disconnected silos of the public service. Despite this he has made it through a 40+ year career as a scientist and for some unknown reason still likes to read scientific papers.

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