The climate impact of crop production
The agricultural sector is frequently reported as an important contributor of climate change, being responsible for 10-20% of total GHG (greenhouse gases) emission. However, a clear estimation of its global environmental footprint is challenging, because not all crops/farming systems are equal, and the choices of individual farmers have an impact that is difficult to calculate. Furthermore, agriculture is one of the few sectors that, besides emission, is also capable of removing CO2 from the atmosphere (through photosynthesis), an element often neglected by emission calculators and climate activists. Importantly, in this website we focus on the carbon footprint of crop production, not considering animal husbandry, as livestocks have a far greater environmental impact and do not contribute directly to sequestering GHG. Despite these difficulties, it is clear that the globalised food markets are far from being ideal from an environmental standpoint. Therefore, facing the current climate crisis, a multi actor effort toward more sustainable production systems is required, with the long-term vision of becoming a sector capable of capturing more GHG than it emits or, which is the same, becoming carbon positive. In order to meet this goal, the first step is to understand when and how much gases are generated during crop management.
Agriculture has the potential to capture more CO2 than it emits.
To this end, crop production is a relatively simple process, which in most cases is composed by a phase where soil is prepared to receive the seeds (or plant small trees), followed by a series of operations, which generally involve passing with the tractor, performed to ensure the growth of healthy plants until harvest time. Therefore, in a typical farm, the two main external inputs that generate GHG are the petrol to power the tractor and the energy (generally from methane) used to synthesise the products applied (e.g. fertilisers and bioactive substances). Among the latter, inorganic fertilisers, and particularly ammonium and nitrate, are by far the products that generate the most GHG in their doing. As a consequence, the two main options to reduce the climate footprint of a farm are: to limit the number of times the tractor is used and; to diminish the amount of fertilisers applied (or, more often, to shift from inorganic to organic fertilisation, which is far less contaminating). A third option is connected to the circular use of residues within the farm, especially when directed to improve carbon stock in the soil. For example, assume one olive farmer burns the branches from pruning, while another uses them to generate compost which is then incorporated into the soil. As a consequence, the action of the first farmer is releasing CO2 back to the atmosphere, while the second is contributing to build up organic biomass for long-term soil carbon storage. Some examples of how land managers can navigate around these options is outlined in the section about agroecology. However, in order to get a first grasp on the global impact of agriculture, another element must be considered, which is linked to the different footprints of traditional vs. intensive farming systems.
Traditional farming systems are the backbone of the Mediterranean diet and food production.
In the Mediterranean region, a large proportion of agricultural land is managed with traditional methods, characterised by a low level of mechanisation and a reduced use of inputs, which therefore generate a reduced carbon footprint. For example, crop residues and animal manure are reintroduced in the growing cycle (today this is called "circular economy"), and crop rotations aiming at maintaining soil fertility are the norm. Unfortunately, these good practices alone can not match the favourable conditions created by high fertilisation dosis typical of intensive farms, and yields are consequently lower. Despite this, traditional systems are still responsible for a large portion of food production and should not be neglected. On the other hand, intensive farming is generally focused on maximising yield, regardless of the inputs used (often misused), and as a consequence have bigger environmental footprints. Addressing the pros and cons of traditional and intensive management, FAO's vision for food systems considers that resilience and sustainability should emerge from the convergence of two processes. From one side, traditional approaches need to modernise and make use of the latest technological development. On the other side, intensive systems need to use inputs more efficiently, aligning with the underlying ecological dynamics that naturally support plant growth. In this context, the Farms4Climate consortium believes that carbon farming can represent a strong convergence force to transform agriculture, especially when the focus is on promoting life in the soil, and increasing carbon storage is a direct consequence of this.
The Farms4Climate project is validating sustainable practices and building synergies toward their upscaling