By Professor Simon Blockley and Professor David Simon, Department of Geography
Relevant United Nations’ SDG goals:
Major adaptation of existing farming practices and crops worldwide will be required to provide adequate food supply and security to the current global population of over 7.5 billion, and projected growth to nearly 10 billion by 2050.
No region, no agro-ecological zone and no food system will be immune from climate-related changes, which will interact in different combinations to push many systems beyond the boundaries of current resilience and the adaptive capacity of subsistence farmers, smallholders, and large commercial farmers alike.
The figure above shows observations and predictions of global temperature anomalies from the previous IPCC Assessment AR5 (2014), suggesting 0–0.50 of warming (over 1986-2005 average) by 2022.
Currently global average temperatures are 0.470 above this average (NOAA), right at the top of the estimate. If this trend continues, the latest IPCC AR6 report projects that we could pass 20C above pre-industrial levels by mid-century, and over 4oC by the end of the century; even with the best outcomes, we are predicted to have 1–1.50C warming by mid-century.
What does all this mean for agriculture? AR6 report suggests significant regional effects, including increased precipitation along the monsoon belt, apart from equatorial America. Reduced precipitation and by extension increased drought is predicted for parts of West and Southern Africa, Southern Europe, and Australia. Even in a 1.50 scenario, regions such as North Africa, the Levant and part of the Americas will warm over 2–2.50 leading to extreme heat.
For instance, exposure to more frequent short extreme heat events might be survivable but in combination with longer periods of extreme and high heat, and reduced rainfall and water availability, and hence possibly also increased soil salinisation, the effects are already becoming greatly magnified. In zones becoming cooler or wetter, the opposite effects will apply.
Solutions do exist. Crop substitution and even ingredient replacement (making bread with non-wheat flour) will therefore be important. This means growing non-traditional crops that can tolerate changing conditions. New varieties of seeds and crops of all kinds are being developed, often blending drought, heat- or salinity- tolerant genes from indigenous crop varieties with faster growing characteristics of conventional varieties.
Replacing commercial monoculture with polyculture and intercropping – techniques that are widely used in tropical and subtropical regions is another option. These take advantage of different soil nutrient and moisture requirements of different species, reduce vulnerability to pests and total crop failure, use taller species to provide shade canopies for adjacent shorter species, and use mulching to help retain soil moisture around plants. Water-smart irrigation is also vital – replacing wasteful conventional spray systems with more specifically targeted and drip-fed systems. Hydroponics – growing plants for food without soil – is also enjoying a revival and expansion, not least because of growing scarcity of fertile arable land and of water.
Beyond that, controlled environment agriculture is expanding rapidly in rural and urban contexts in order to optimise nutrient and water inputs and maximise quality and yields. These are capital intensive but could compare favourably with greater food miles of imported foods they replace. This winter, the first large-scale crop of winter strawberries is being grown indoors in England, targeting the Christmas and early spring supermarket trade with enhanced quality and lower prices than imports.
The level of new agri-food investment required for all this in the global South was calculated by the recent Commission on Sustainable Agricultural Intensification at US$ 15.2 billion. This represents only a tiny fraction of current global foreign direct investment flows or the value of food imports, and yet if enacted would represent a positive step towards enhancing global food security. As befits our predominantly urban world, sustainable food supply is increasingly being secured – for certain categories of vegetables, at least – in urban as well as rural areas.