SDG 15 – Eating up life on land

Life on land sets out to protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, halt and reverse land degradation and halt biodiversity loss.  The way we produce food has major impacts on this goal, both directly through agriculture encroaching forest land and causing degradation of land and freshwater resources; and, indirectly by contributing to climate change that is, in turn, a driver of biodiversity loss. On top of this, land and water degradation and biodiversity loss reduce our capacity to produce food.

 

A recent article in Nature shows that the interaction between historical climate warming and agricultural intensification has caused numbers of insects to reduce by nearly 50% while species diversity has gone down by 27%, with effects more prevalent in tropical than temperate regions. These negative impacts of agricultural intensification on insect abundance are observable in protected areas as well as in agricultural landscapes.   There is then a pernicious feedback on hunger, measured as prevalence of malnutrition, because insects are important pollinators of crops.  It has been estimated that yield loss caused by insufficient pollination is greatest in lower-income countries, with estimates suggesting 26% of vegetable production and 8% of nut production may be lost, leading to inadequate nutrition, that is, in turn, associated with decline in human health.

 

Far from being on course to achieve the SDGs, it appears as though the situation for food, biodiversity and climate change are all getting worse at the same time and aggravating one another. The number of hungry people in the world has been steadily growing since 2015 with 736 million estimated to be undernourished in 2021 while global forest loss has steadily progressed since 1990 and remains stubbornly high (net loss of 11.1 million ha in the tropics in 2021, including 3.75 million ha of primary rainforest). Land degradation progresses despite impressive commitments to restoration; and, biodiversity loss is accelerating with an 11% decrease in the Red List Index that measures conservation status of major species groups from 1993 to 2022 amidst predictions that climate change will aggravate extinction risk.

 

It is perhaps not surprising then that policy makers are increasingly turning to the transformation of food systems as critical for addressing biodiversity loss and climate change as well as hunger. A problem remains that much of the rhetoric about transformation is actually only advocating for incremental improvements in the efficiency of an outdated model of agriculture based on sustaining crop monocultures with environmentally disruptive chemicals, alongside largely separate intensive livestock production. The transformation that is needed requires shifts in what people consume, reduction in food loss and waste and development of integrated production systems that are equitable and operate in harmony with nature rather than cause environmental damage.

 

Agroecological principles offer a promising solution. They have been clearly articulated and their implications for food system transformation have been widely recognised. Agroecological practices resulting from local application of these universal principles, have been found to increase the resilience of farming systems to climate change effects, as well as mitigating greenhouse gas emissions through using less fossil fuels in production and increasing carbon storage in soil and vegetation.

 

What has changed the game recently is that a positive relationship between crop diversity and productivity has been empirically established through analysis of long-term data from extensive trials across Africa and Europe. This shows crop yield increasing with higher crop diversity and, that where legumes are integrated, they substitute for application of inorganic nitrogen fertilizer. This is reinforced by global metanalysis of over 400 trials, showing that integrating legumes in rotations increases main crop yield (by 20% on average), with effects larger where less inorganic nitrogen fertilizer is applied.  Global analysis of the impact of integrating trees with rice, also showed higher yields of rice with trees than without, where no or low levels of fertilizer were applied and crop yields were maintained in large scale transition to agroecological farming in Andhra Pradesh, with higher yields in agroecological than conventional systems, associated with higher soil moisture, lower soil temperature and greater abundance of earthworms.

 

Crop diversity has also been positively correlated with dietary diversity at national level and in a global metanalysis of comparative studies 78% found evidence of a positive relationship between agroecology, and, food security and nutrition, with the effect increasing with the complexity of the agroecological approach.  In line with this mounting evidence, the IPCC sixth assessment report concluded that agroecological principles and practices support food security, nutrition, health and well-being, livelihoods and biodiversity, sustainability and ecosystem services.

 

Transforming food systems through application of agroecological principles will not be easy because it requires a fundamental change from monoculture sustained by application of environmentally disruptive chemicals to integrated production systems that are often knowledge rather than capital intensive. Much agricultural and food system policy as well as practice in the private sector, locks-in high-input monoculture so that fundamental change to markets and governance are required to effect change. Achieving this involves challenging the prevailing status quo and so will inevitably be uncomfortable. It is clear what needs to be done, what remains to be seen is whether people and policy makers will have the courage to embrace transformational change with the urgency required to sustain life on land while achieving zero hunger.

 

The article is based on data collected from these sources.