Agriculture and climate change are clearly and inextricably linked. Large-scale agriculture contributes to climate change (through methane, fertiliser emissions, land clearing, mono-cropping, etc.), but it is also very vulnerable to the effects of climate change, particularly when this relates to water supply.
Extreme weather events can have a negative impact on crop yields, nutrient contents, livestock, fisheries, aquaculture, and land use. A changing climate also results in changes in the distribution of pests and diseases affecting crops.
A daunting prospect
In order to assist governments in the wake of the Paris Climate Agreement, the Intergovernmental Panel on Climate Change released a report in October 2018, which highlighted southern Africa as a climate change hotspot. Temperature increases in southern Africa are projected to be higher than the global average, and the number of consecutive dry days in the region is expected to increase, while soil moisture is expected to decrease.
The current relationship between agriculture and climate change in South Africa can be summarised as follows:
Source: WWF Report, 2019
At the beginning of June 2019, Stats SA reported that the SA agricultural economy had contracted on a quarter-on-quarter basis by a seasonally adjusted and annualised rate of 13.2%, Climate-related factors, including the severe drought in several regions, were a major contributor to this contraction. By example, the Western Cape Economic Opportunities Department reported that the drought had resulted in a loss of 30 000 jobs in the agricultural sector in the Western Cape alone during 2018.
So, what are we to do?
It is clear that both sides of the climate change equation need to be urgently and creatively managed, in order to have a responsible and sustainable way forward. On the one hand, this involves ongoing, concerted effort to reduce and, where possible, eliminate destructive agricultural inputs to climate change. On the other hand, agricultural operators need to adapt to, and pre-empt where possible, the increasingly critical impact of the changing climate.
You can’t manage what you don’t measure
Measurement is a prerequisite for effective management of both resource-use efficiency and emission reduction. Farming operations, especially those with large-scale irrigation equipment or packhouse operations, have a strong commercial driver to manage their carbon footprint – in addition to the equally strong ethical driver for farms to align with industry good practice in reducing their climate-impacting emissions.
Farming hotspots
Electricity consumption for the pumping of water is the largest source of farm-level carbon emissions, since South African grid-supplied electricity is predominantly coal based. The most significant factors determining the energy requirements are the irrigation intensity of the crop and the pumping ‘head’ of the farm. The second biggest emitter at farm level is the usage of synthetic nitrogen-based fertilisers, as their production is energy-intensive and the inefficient application of synthetic nitrogen fertilisers results in large volumes of nitrous oxide emissions, a very powerful greenhouse gas. Diesel usage is the third largest emission source and relates to the use of a variety of vehicles and equipment for spraying, harvesting, soil preparation, transportation and other farming activities.
On crop farms, most emissions at a packhouse level are related to the production and use of packaging material. Packhouses may lower their footprint by using more environmentally friendly packaging material or reducing the amount of packaging material, but there are often restrictions on this when exporting fruit.
With these considerations in mind, the farms in the Futuregrowth Agri-funds have joined the ‘Confronting Climate Change’ initiative, which provides a freely available on-line carbon emission calculator, together with technical training supporting its adoption and use. With this, the fund farms and packhouses can accurately measure the energy-use and carbon-emission intensity of their business activities. Once these parameters have been established, farms are able to use the data to evaluate where they can realistically reduce energy use and emissions.
Thirsty work
Agriculture is responsible for approximately 70% of the world’s fresh water consumption, in an era when global water security is increasingly compromised by growing demand, in addition to climate change-related pressures. It is essential to acknowledge the gravity of the world’s water situation and the need to balance essential food production requirements against water security requirements.
Source: WWF Report, 2018
Water resilience strategies need to be tailored to every farm, taking into account local conditions as well as best practice water-saving initiatives for the specific commodities farmed. These might include:
- Optimising irrigation systems, including the use of central computerised oversight and control (to save both water and electricity);
- Diversifying water sources, such as combining borehole and surface water abstraction;
- Clearing alien plants in water canals ;
- Lining storage dams to prevent seepage;
- Installing netting over orchards to reduce evaporation;
- Developing soil moisture management plans, using, for example, neutron probes to measure the quantity of water present in soil;
- Selecting and planting cultivars suited to water availability and soil type; and
- Planting cash crops to act as a living mulch in orchards – amongst others. A living mulch is a cover crop interplanted or under sown with a main crop, and intended to serve the purpose of a mulch, such as weed suppression, regulation of soil temperature and reduction of water run-off and soil erosion.
Holistic solutions help to close the circle. The removal of invasive alien plants contributes to plant and animal biodiversity, and diminishes the likelihood of flooding, fires, and erosion. The destruction of rivers and siltation of dams and estuaries is also foiled by these practices. Cover crops (such as rye, oats and grasses) and other soil stewardship practices also increase organic matter and improve soil quality, save water, minimise crop losses and reduce carbon pollution by absorbing CO2 from the air.
The changing face of farming
While some large-scale operations can fuel the perception that agriculture is environmentally unsound (and this is certainly true of projects that are not well managed), economies of scale can allow operators to invest in – and therefore support the development of – breakthrough technologies and novel practices.
We are seeing technology increasingly used to measure and control agri impacts, and enhance outputs. These range across:
- Deforestation measurement tools and other better information systems;
- The use of drones to precisely track crop health and reduce water and chemical inputs;
- Using blockchain technology to ensure supply chain traceability; and
- Indoor farming operations which are highly productive and independent of weather patterns.
These innovations are evolving, with some still in their infancy and others becoming increasingly mainstream.
Managing the impact of climate change is going to take the participation and combined effort of all the stakeholders in agriculture. Now, more than ever, judicious investment in the sector is needed, to enable and support farm operators in pursuing new solutions to the challenge. We have no other option.
Read our related article on Counting the cost: What will South Africa's carbon tax mean for farmers?
