Saving the soil that feeds us
The confluence of conflict and climate-related shocks such as drought and floods is threatening global food security. What is particularly alarming is the continued degradation of soil, with a UN report warning that one-third of the world's land has been severely degraded and fertile soil is being lost at the rate of 24 billion tonnes a year. Clare Westwood examines this grim situation and what can be done to save the soil.
GLOBAL hunger is on the rise. In 2016, the number of chronically undernourished people in the world increased to an estimated 815 million, up from 777 million in 2015, according to a recent United Nations report.1 The world is home to 155 million stunted children and wasting continues to threaten the lives of almost 52 million children (8% of children under five years of age), while childhood overweight and obesity rates are on the rise in most regions and in all regions for adults.2
The food security situation has visibly worsened in parts of sub-Saharan Africa and South-Eastern and Western Asia.3 Deteriorations have been observed most notably in situations of conflict, exacerbated by climate-related shocks like droughts and floods.
The UN report, The State of Food Security and Nutrition in the World 2017, states: 'The concurrence of conflict and climate-related natural disasters is likely to increase with climate change, as climate change not only magnifies problems of food insecurity and nutrition, but can also contribute to a further downward spiral into conflict, protracted crisis and continued fragility.' The report identifies several countries where a conjunction of conflict and climate-related shocks was associated with food crisis situations in 2016, including South Sudan, which was hit by both drought and floods, and Yemen, where flooding, heavy rains and tropical cyclones impacted adversely on food security.
The recent increases in hunger and undernutrition figures pose a significant challenge to realising the goal of ending hunger by 2030 as per international commitments in the 2030 Agenda for Sustainable Development. While it is not yet clear whether this recent rise in hunger and food-insecurity levels signals the beginning of an upward trend, or whether it reflects an acute transient situation, one thing is clear: we will not end hunger and all forms of malnutrition by 2030 unless we address all the factors that undermine food security and nutrition. And one of those factors is the rapid pace of soil degradation globally. Good soil is a fundamental aspect of food security. But the viability of soil is being threatened by human activity as well as climate change.
Soil is the largest land-based reservoir of carbon on Earth, absorbing it from trees and vegetation as they die and decay.4 The soil stores four times more carbon than all trees and other life on Earth.5 Soil microbes (the tiny bacteria, fungi and other micro-organisms that determine soil health) are fundamental to countless ecosystem services such as producing humus (the dark organic material in soils) and providing a critical water filtration system for trees.6 The health and vitality of soil everywhere, from the smallest backyard garden to the largest farm, plays an essential role in food production.
Alarmingly though, soil is being destroyed at a rapid rate. If we continue to degrade our soils, we will not be able to feed the world in the future. A 2017 United Nations Convention to Combat Desertification (UNCCD) study reports that a third of the Earth's land is severely degraded and fertile soil is being lost at the rate of 24 billion tonnes a year.7 In 2009, the international farmers' rights NGO GRAIN had already calculated that in the previous 50 years, the massive use of chemical fertilisers and other unsustainable practices of industrial agriculture had caused an average loss of at least 30-60 tonnes of soil organic matter for every hectare of agricultural land.8 This translated to a total loss of at least 150-205 billion tonnes of organic matter over the period.9 In any event, carbon losses from the intensive use of chemicals on soils, ploughing up grasslands, and clearing forests and peatlands constitute the second-largest source of carbon dioxide, after burning fossil fuels.10
Heavy tilling, multiple harvesting and the over-use of agrochemicals have increased yields, but this has come at the expense of long-term sustainability. In the past 20 years, agricultural production has increased threefold and the amount of irrigated land has doubled.11 This diminishes fertility, which can lead to land abandonment and desertification. The UNCCD study mentioned above noted that decreasing productivity could be observed on 20% of the world's cropland, 16% of forest land, 19% of grassland and 27% of rangeland.12
The same study cited high levels of food consumption in wealthy countries as another reason for soil degradation in developing and least-developed countries.13 Such demands are expected to continue to grow. The UNCCD study forecasts that by 2050, sub-Saharan Africa, South Asia, the Middle East and North Africa will face the greatest pressure unless the world sees lower levels of meat consumption, better land regulation and improved farming efficiency.14 Over-grazing by livestock due to high meat consumption contributes greatly to soil degradation.15 Soya production, mainly for industrial animal feed, has destroyed forests and ecosystems in Latin America.16
Against this grim scenario, we have climate change.
Climate change is a serious threat to soil health. Soil health is closely related to water and water is key to all agriculture.17 The climate crisis has fundamentally altered the water cycle around the world. The result is shifting precipitation patterns and increased evaporation which result in more frequent severe rainfall events and more severe droughts. In many areas, rainfall has become either increasingly abundant or in desperately short supply, relative to long-term averages.18
Extreme downpours can lead to runoff and erosion because the ground is simply not able to absorb the precipitation at the rate it is falling. This strips healthy soil of key nutrients needed to sustain agriculture. In urban, suburban and agricultural areas, this runoff can pick up pollutants from the land and carry them down to rivers and other waterways. Furthermore, when a powerful downpour occurs in an area without adequate trees and other vegetation to hold the soil in place, a landslide can happen. In coastal areas, sea-level rise can lead to increased groundwater salinisation due to the intrusion of salt water inland. This will reduce the availability of fresh water for home consumption as well as for garden and farm irrigation.
On the other side of the coin, reduced precipitation together with rising temperatures is causing increased desertification, leading to a complete loss of farm production in many areas. Frequent droughts and enhanced evaporation are killing off the vital living soil ecosystems necessary to grow healthy crops. In addition, they leave less water to dilute even relatively common pollutants in rivers, streams, lakes, wells and reservoirs. It is projected that Asia's mountain glaciers will lose at least a third of their mass through global warming by the end of the century, with dire consequences for millions.19 These glaciers feed many of the world's great rivers, including the Ganges, the Indus and the Brahmaputra, on which hundreds of millions of people depend for freshwater.
The climate crisis thus has a profound impact on every drop of water on the Earth's surface. The viability of home gardens and farms, and the availability of fresh, healthy and affordable food everywhere is directly threatened when climate changes and there is either too much or too little water. Another 2017 study projects that rising temperatures and increasing extreme weather events could reduce global production of maize, wheat, rice and soya by 9% in the 2030s and up to 23% in the 2050s.20
Another impact of climate change on soil health is through its effect on soil microbes. A 17-year study21 into the effect of global warming on microbes found them to be far less adaptable to changing conditions than previously expected. This means that we cannot assume that microbes, and therefore the soil, will respond to climate change in a way that many scientific models have assumed. This finding thus raises concerns that the microbes will not be able to carry out essential functions, such as breaking down leaves and other organic matter in a process which converts them into nitrogen and other nutrients that plants need to grow. Soil is the major buffer system for environmental changes, and the microbial community is the basis for that resilience. Therefore, if the microbial community is not resilient to climate change, then it calls into question the resilience of the whole environment to climate change.22
What then should be done to save soil? Clearly, agroecology is the way forward to ensure soil health and abundant food production as well as effective carbon sequestration. The UNCCD study called for a shift away from destructive intensive agriculture.
Already in 2009, GRAIN calculated that, by using sustainable farming techniques, we could progressively increase soil organic matter by 60 tonnes per hectare over 50 years, and capture a large chunk of the excess carbon dioxide in the atmosphere.23 Agroecological methods would include 'no-till farming', which eliminates the manipulation of the soil for crop production. This should ideally be combined with cover cropping using non-cash crops like clover or small grains to protect soil from erosion, weeds, pests and diseases; decrease nutrient loss; and improve soil fertility and biodiversity between periods of regular crop rotation.24 This will build soil organic matter which will trap carbon; act as a shield over the soil to protect it during dry times; act as a sponge to protect the soil from heavy rains; add nutrients to the crops; and provide water quality benefits.
Another good move would be to turn exhausted cropland to pasture land to protect soils and build soil carbon while still producing food.25 Small numbers of animals that eat grass and arable by-products which humans do not eat could be good for the environment, provided of course that these pasture lands do not encroach upon critical wildlife habitats such as forests and peatlands. Low-intensity grazing will allow fallow land to remain productive, which will encourage farmers to protect their soils and reduce pressure on the land.
Last but not least, changing our eating habits from high amounts of industrially raised meat to far smaller quantities of higher-quality, mainly grass-fed meat or going vegetarian entirely, along with less dairy, more ecologically grown fruit and vegetables, and less processed food will make a big difference to sustainable global soil and food security.26
Clare Westwood is a writer and researcher on food, agriculture, climate change and agriculture, and biosafety for the Third World Network.
6 Bond-Lamberty, B. et al. 2016. 'Soil Respiration and Bacterial Structure and Function after 17 Years of a Reciprocal Soil Transplant Experiment'. PLOS ONE. Cited in independent.co.uk/environment/climate-change/soil-crisis-brought-about-by-climate-change-may-hit-global-food-production-claims-alarming-new-a6970376.html
7 UNCCD (United Nations Convention to Combat Desertification). 2017. The Global Land Outlook. Cited in https://www.theguardian.com/environment/2017/sep/12/third-of-earths-soil-acutely-degraded-due-to-agriculture-study
10 Sauven, op. cit.
11 UNCCD, op. cit.
15 Sauven, op. cit.
21 Bond-Lamberty et al., op. cit.
23 GRAIN, op. cit.
24 The Climate Reality Project, op. cit.
25 Sauven, op. cit.
26 Ibid. See also Smithers, R. 2017. 'Vast animal-feed crops to satisfy our meat needs are destroying planet'. The Guardian. http://www.theguardian.com/environment/2017/oct/05/vast-animal-feed-crops-meat-needs-destroying-planet
*Third World Resurgence No. 322/323, Jun/July 2017, pp 31-33