Agriculture is a key piece of the puzzle to feeding the world but is it a part of sustainable development? Can agriculture contribute to the United Nation (UN) Sustainable Development Goals and the UN 2030 Agenda - to end poverty, protect the planet and ensure peace and prosperity? 

 

United Nation (UN) Sustainable Development Goals consist of 17 goals: 
 

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There are opportunities for agriculture to contribute positively to these goals. A social-ecological system perspective is key to understanding these goals with respect to their social, ecological, and economic drivers, process, and impacts. 

 

The current narratives about agriculture and ecological changes tend to focus on agriculture as one of the major contributors to greenhouse gas (GhG) emissions. This is true, but there are more to that. Firstly, agriculture has contributed to other social-ecological stressors. Secondly, the ‘right’ agriculture could mitigate and prevent some systemic ecological and social problems.

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Global perspective on the link between agriculture with a myriad of ecological changes

 

Industrial agriculture was deemed a panacea for an increasingly populated world. Agricultural production has more than tripled since the 1960s, supporting the need for food, feed, and fibre. We saw a rapid and increasing intensification in the use of land, water, synthetic fertilisers, chemical pesticides, and high-yield cereal hybrids promised to reduce hunger and stimulate economic development. 

 

Agriculture has, directly and indirectly, contributed to various abrupt and gradual changes in ecological and human systems at the global and regional level, such as biogeochemical (carbon, water, nitrogen-phosphorus, oxygen, sulphur) cycles changes and imbalances, biodiversity loss, land degradation and deforestation, which also intensify the vulnerability and sensitivity of biodiversity, food security, human health and human livelihood to ecological changes and variability. The interlinkage, nature, magnitude, spatial extent, and reversibility of these changes, abrupt and gradual, have an immense impact on our planet earth and life on earth.

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Carbon and Soil Carbon Sequestration

 

Since the pre-industrial period (1850-1900), the world has warmed around 1.2 - 1.5C1, land surface air temperature have seen nearly 1.8C warming, while the oceans have warmed around 0.8C. These increases have been associated with higher and unprecedented frequency and magnitude of social-ecological events around the world - droughts, rains, floods, forest fires, coral bleaching, heat waves, and storms. 

 

As a whole, globally, agriculture2 is responsible for 1/5 of carbon dioxide emissions, 1/3 of Methane (CH4) emissions, and  2/3 of Nitrous Oxide (N2O) emissions. It has been argued that agriculture has a decreasing share of total global anthropogenic emissions, for instance, in the 1990s, it was responsible for around 29% of emissions, 24% in the 2000s, 21% 2010s (Tubielli, 2015)3 and around 18.4% by 20204. The main reasons driving the global decline? A fall in the emissions from deforestation and land-use change, and a rise in the total of anthropogenic GhG emissions. Whilst the emissions from deforestation has fallen, the emissions from agriculture have risen over the last half of a decade.  

 

The view of forests as carbon-sequester has been established for decades. Trees capture carbon dioxide from the atmosphere, sequestered carbon is then accumulated in the form of biomass, deadwood, litter, and in forest soils. The release of carbon from forest ecosystems results from natural processes such as respiration and oxidation as well as from human activities such as harvesting, deforestation, and fires. 

 

The view of agriculture as carbon-sequester is however still largely debated. Academics in soil science have studied and estimated the potential of carbon sequestration in soil organic matter for almost two decades. The premise: nearly 10,000 years of cultivated agriculture has reduced global soil carbon by 116 Gt5, an amount equivalent to more than a decade of the present rates of industrial emissions6.

 

It is proposed, through changes in agricultural techniques, the legacy load of carbon can be restored to soils, thus serve as a significant tool to feed humanity and to mitigate climate change. Scientific research in this particular field is at its nascent stage, scientific evidence so far showing a spectrum of pessimistic and optimistic observations. Whilst there is an increasing consensus that reducing soil erosion will reduce carbon leakage, the evidence of specific agriculture practices leading to the retention of carbon in the soil in still debated. Critiques argue that it offers temporary carbon storage and is be highly sensitive to changes in agricultural management practices. 

 

The research in agricultural practices contributing to increasing topsoil health which in turn increase the wider system’s social-ecological adaptability to different ecological stressors such as precipitation, wind, and wave are increasingly exciting. Markets should pay attention to these developments. For instance, agricultural activities rely heavily on water. The sector accounts for about 70% of global fresh-water use and is a major water polluter, highlighting the role of agriculture as a sector that contributes to and faces the risks of ecological changes. Agriculture has also been linked to desertification. According to the United Nation, more than 1 billion people in over 100 countries face some level of risk related to the effects of desertification. Climate change can further increase the risk of desertification. Whilst, desertification is reversible, it requires concerted civil and industrial actions and agriculture proffers some potentials.

 

US

In the US, figures in 2018 suggest that agriculture accounts for 9.9% of GHG emissions, land use, and forestry 11.6%, transportation 28.2%, electricity production 26.9%, industry 22.%, commercial and residential 12.3%. 

 

Since 1990, the US government has largely view managed forests and other lands are a seen as a net sink. The view of agriculture as carbon sequestration opportunities is increasing in a section of the farming communities and yet seen in public policies. 

 

UK

The UK Government has pledged to adopt policies that will reduce greenhouse gas (GHG) emissions across the economy by at least 80%, from 1990 levels, by 2050. This is In line with the requirements set out in the Climate Change Act 2008 and as part of its international obligations. 

 

With 10% of net greenhouse gas emissions in the UK were estimated to be from the agriculture sector, 28% from transport, 23% from energy supply, 18% from business, and 15% from the residential7, it places agriculture as the 5th most important driver. If we look beyond carbon dioxide emissions, agriculture is responsible for 70% of total nitrous oxide emissions and 49% of total methane emissions. Emissions of methane largely come from the enteric fermentation from livestock, particularly cattle; and nitrous oxide emissions related to the use of fertilisers. In the UK, between 1990 and 2018, GhG emissions from agriculture decreased by around 16%, with a general downward trend in emissions since the late 1990s8. This was driven by a fall in animal numbers over the period, together with a decrease in synthetic fertiliser use. 

 

But one key but the relatively unknown fact is that UK soils currently store about 10 billion tonnes of carbon, roughly equal to 80 years of annual UK greenhouse gas emissions9. This may correspond with the other important fact, that  72 - 74% of the UK land area10 is agricultural area11. The total utilised agricultural area in the UK has remained between 17 and 18 million hectares since 2001. In 2020, the total utilised agricultural area in the UK is approximately 17.5 million hectares, with the total croppable area at approx. 6.1 million hectares, covering 25% of the total land area in the UK.

 

Interestingly, whilst the government or rather DEFRA see soil as an important natural capital resource that provides ecology and humanity with many essential services, termed ecosystem services, Yet, contrary to the OECD12, for years, the UK government has taken the position that potential in the UK  to which soil carbon sequestration can offset agricultural emissions in the UK is uncertain and that potential in the UK is limited. 

 

Academics, however, have been unraveling the potential of soil as a key compartment for carbon sequestration (Lal, 2014; Minasny et al., 2017). To date, most studies found the potential to be hinged on the net biome productivity and the soil quality (Bispo et al., 2017) which correspond with not just climatic, ecological and land-use changes but also specific to farming methods. 

 

A recent global study on soil lifespan showed that topsoil health can be rapidly extended by changes in land use and management highlighted or rather refute a narrative13 that have been circulated in media - there is 60 years of farming or harvest left if we do not convert to minimal- or zero- tillage farming systems. This narrative has been espoused by a recently launched Hollywood star-studded documentary titled ‘Kiss the Ground’. 

 

There is research that suggests zero-tillage practices may induce an increase in N2O emissions thereby offset potential benefits from CO2 reduction. Reflecting DEFRA’s concerns, the academic uncertainty remains in regard to the extent to which zero-tillage14 can sequester more carbon throughout the soil profile, with some studies highlighting incorrect sampling and calculation methodologies have overestimated the potential of zero-tillage in carbon sequestration. A new study showed global warming potential was at least 30% lower from zero-tilled soils compared to conventionally tilled soils, primarily driven by lower CO2 emissions under zero-tillage. However, the consensus on good soil management practices positively influencing and extend top soil heath remains, along with the potential for geochemical rebalancing and mitigating CO2 emissions. 

 

At the moment, the UK government sees peat soils15 as a significantly larger potential for carbon sequestration. Only £12 million has been invested in the research in this area. 

 

Despite agriculture’s relatively high contribution to GHG emissions, agriculture is not yet subject to emissions caps under the Kyoto agreement to fight climate change. Government in some countries are taking actions, we see that in global and particularly finance industry-led initiatives in climate risks and biodiversity loss reporting. 

 

The potential for carbon sequestration in agriculture will be discussed further in the next article. I will also discuss the uptake of mitigation methods by small-scale farmers, and the potential of regulatory and market instruments to provide for natural ecosystem services.