Feeding the world without destroying it: Part 1

| 23rd June 2020
Growing food
Our food system needs immediate and radical reform if we are to feed the world without irreparably damaging our global resource base.

To truly achieve global food security, we need to work out the complex social and geopolitical factors surrounding the food system.

Uncertainty and dissatisfaction surrounding the global food system has mounted steadily over the past few decades. During this time, we have seen yield gains from the Green Revolution reach their bounds, while the environmental consequences of such intensive production is becoming ever more apparent.

Despite the global push for ‘productivity at all costs’, the proportion of the population that is malnourished has plateaued at around 10.8 percent since 2015 - meaning today there are some 820 million people still receiving insufficient nutrition. Changing consumption patterns, volatile global markets, and food waste of 30-40 percent mean that these extra calories are not reaching those who need them.

In the third episode of “Ask A Scientist Live”, Extinction Rebellion scientists brought together four experts in agroecology and food systems to tell us more about the issues facing our food system, and why they believe that agroecology is the solution. 


It is evident that the food system needs immediate and radical reform if we are to feed the world without irreparably damaging our global resource base.

The challenges the food system needs to address are complex and daunting. While the rallying cry of agribusiness to “double food production by 2050” may be an over exaggeration, increases of 25-75 percent over 2010 yields will still be needed to feed a growing population.

Lack of land and resources means that these increases cannot come from agricultural expansion, and will have to be attainable in the face of increasing climatic instability.

Furthermore, to truly achieve global food security, we need to work out the complex social and geopolitical factors surrounding the food system to ensure that consumers from all income levels and geographic areas have access to healthy, affordable food regardless of market perturbations and speculation.

In 2019, the UN Committee on Food Security recognised that agroecology was a way to achieve ecological food production as well as addressing the social and economic inequalities that contribute to rural poverty and uneven distribution of food. 


Dr Marco Bertaglia is an honorary research associate of Imperial College who works at the Joint Research Centre in Northern Italy. He has witnessed widespread degradation of the soil in valleys around the centre, predominantly due to intensive farming.

To truly achieve global food security, we need to work out the complex social and geopolitical factors surrounding the food system.

As well as causing greenhouse gas emissions, degraded soils are a major threat to agriculture. Even in non-tilled soils, erosion can exceed the rate of soil formation by 10-20 times; in conventionally tilled soils, it can be over 100 times faster - meaning that the ground is quite literally dropping from beneath our feet.

Bertaglia recognises that this is not necessarily the fault of the farmers. Chemical fertilisers were developed in the early 1900s, long before scientists knew the importance of balanced biogeochemical cycles. But historical over-application of fertilisers, combined with continuous tillage “destroys microbiology of the soil, fractures it, and creates the condition for less absorption and more emission of carbon fertilisers”.

These practices also mean that earthworms cannot compensate for the loss of topsoil - they too are being lost from intensive fields, to the point where only 20 percent remain. This has created a vicious cycle, where more and more inputs are required just to regain the lost fertility.

Every damaging practice that occurs during production has been amplified by the trend towards supersized farming. Larger farms usually grow monocultures across hectares of land, making it easy to plant and harvest using fossil-fuel driven machinery. Importantly, to achieve high yields the plants are dependent on vast quantities of fertilisers and pesticides; without a precisely tailored environment, the crop can produce near to nothing.


It is also important to remember that the effects of agricultural expansion and intensification are felt far beyond the farm gate. A total of 75 percent of all terrestrial and 66 percent of all marine ecosystems are altered or severely altered by humans.

Agriculture plays a disproportionate role in this alteration - urban development takes up less than one percent of habitable land, as opposed to agriculture’s 50 percent.

Extinction Rebellion's panel gave us a few examples of ways that agriculture has contributed to acceleration of biodiversity and ecosystem deterioration during the past 50 years.

Fertilisers can cause algal blooms that starve lakes and seas of oxygen, creating ‘dead zones’ that have quadrupled in size since the 1950s. Up to 40 percent of insect species are at risk of extinction due to the effects of pesticides on target and non-target species. Our livestock systems are particularly unsustainable, with beef rearing and soy cropping for animal feed as the main two drivers of deforestation.

The food system is also unstable. The expansion of agribusiness has removed control over food production from many farmers and placed consumers at the whim of the market, meaning that shocks such as the 2008 financial crisis and the recent coronavirus epidemic often lead to closing borders and skyrocketing prices.

This could be detrimental for countries such as the UK, where over 50 percent of food is imported, but also for net exporters who now lack the markets and infrastructure to redistribute food locally.


Agroecology is a broad term to describe farming in a way that imitates natural biogeochemical cycles, harnessing synergistic ecological interactions to benefit both agriculture and the environment. The panelists believe it could solve many of the above problems.

Practices such as minimum-tillage, mulching, growing polycultures, and using cover crops create a rich, fertile soil that is less susceptible to loss of soil particles or of nutrients.

Researchers have calculated that with this type of management, global croplands could be a net sink for carbon, sequestering up to 1.85 billion tonnes of carbon a year (around five percent of current annual emissions).

Agroecological farms encourage diversity in crops and livestock, with mixed farms and intercropping as common practices. The complexity can pose challenges for farmers who are unfamiliar with these methods.

But Dr Lynn Dicks, a conservation scientist from the universities of Cambridge and East Anglia, believes the resilience they provide is more than worth the effort: "You get these stable systems that are very intricate in their detail, and yet they continue to provide ecosystem functions; they produce biomass, and in general they're surprisingly stable given their complexity.”

These farms are also highly productive, a phenomenon termed the ‘inverse size-productivity relationship’. The cause could be that smaller farms receive more care, usually employing many more people on a per hectare basis, or due to the ingenuity of farmers trying to maximise output without exploiting their land.


Using a cover crop overwinter provides forage or a winter grain harvest, while protecting soil from erosion or leaching. Feeding waste to pigs and chickens takes care of waste disposal, while also directing more calories back into the food chain. Rotating cows on arable fields clears crop stubble and fertilises the soil for the next crop, while the cows receive a nutrient rich diet.

The circularity within agroecological systems ensures that all resources are used as efficiently as possible.

Jyoti Fernandes is a policy director for the Landworkers’ Alliance and honorary research fellow at Coventry University. Her work with UK and international farmers has highlighted another important aspect of agroecological farms - they typically produce food for local communities.

Fernandes said: "Small scale farmers who practice agroecology are producing food out of a sense of love for the land, love for the natural environment, to feed their families and their communities and their regions with good healthy nutritious food. It's not about profit at all costs … It's much more about the values that we farm with.”

Local supply chains could help to tackle many of the issues contributing to food insecurity, as well as cutting down on greenhouse gas emissions and pollution arising from transport and packaging of products for the global market.

Read Part 2 now!

This Author 

Ele Saltmarsh has a BA in Biological Sciences from Oxford University and currently is a doctoral researcher in Agricultural and Environmental Sciences at Penn State University. The back catalogue of all the episodes of ‘Ask a Scientist Live’ can be found here.

Image: Kath Clark/USC Canada, Flickr

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