Food security is one of greatest challenges of the 21st century: by 2050, food production must increase by 70% to meet the demands of 9 billion people. Progress towards this target must occur in a climate with higher temperatures, more variable rainfall patterns and more frequent episodes of extreme weather. The scale of this challenge is highlighted by the evidence showing changes are already having a serious impact on each of the four dimensions of our global food security: food availability, stability, access and utilisation.
Food availability is concerned with crops yields and therefore the capacity of the agricultural system to meet the demand for food. While higher temperatures will increase the area of agricultural land and extend the length of the growing season in temperate latitudes, these gains have to be set against an increased frequency of extreme events. By 2050, the UK’s Global Food Security Programme found that a once in a century crop failure linked to extreme weather could occur every 10 years. This is easy to believe given the two-month drought and heatwave that hit the UK this summer: the Environmental Agency found that UK experienced the driest June since 1925 and that “cumulative rainfall totals for July were 4% of the July long-term average in eastern England”. As a result, staple foods such as potatoes, bread and onions are likely to be in short supply come winter. Climate scientists have since revealed that the heatwave was made “more than twice as likely” by climate change. The threat of more frequent droughts is exacerbated by the fact the regions of the world that are most vulnerable to drought are also those with the most undernourished people.
Food stability is at risk from the short-term fluctuations in food prices caused by climate variability. The poor in subSaharan Africa and South Asia are most sensitive to rises in staple food prices, as staple foods account for a significant proportion of their income. The political instability triggered by such food shocks also affects the West. In 2010, wildfires and drought reduced wheat production in Russia, and the subsequent export ban sent food prices soaring in consumer countries, helping to spark the Arab Spring.
Food access refers to the ability of individuals, communities and countries to purchase sufficient food, and differs from food stability in that it concerns longer time spans. Over the last 30 years, falling food prices have led to improvements in food security e.g. in East Asia, rises in income growth have caused hunger to decline from 24% to 10.1% between 1970 and 2001. At the regional level, the economic output from agriculture is crucial to food security, yet this output is being compromised by variable climatic conditions and extreme weather events. For subSaharan Africa, the Commonwealth Scientific and Industrial Research Organisation finds that losses in agricultural GDP in scenarios with climate change are 7-9% higher than in scenarios without climate change. Additionally, the prices of basic resources, such as land and water, are changing: land with access to a steady supply of water will rise in value, whereas land on the floodplain is depreciating.
Climate change is limiting the ability of individuals to consume food effectively by adjusting the conditions needed for food safety and increasing the abundance of vector- and water-borne diseases. Scientists fear a vicious cycle, in which infectious diseases weaken the local population, thereby increasing their susceptibility to further disease and reducing labour productivity on agricultural land. Higher temperatures promote microbial growth on fresh fruit and vegetables and studies have shown there is a linear increase in reported cases of salmonellosis for every extra degree in weekly temperature. Additionally, extreme rainfall events increase the incidence of water-borne diseases in regions lacking adequate sanitation. Less than two weeks after Hurricane Matthew made landfall in Haiti, the World Health Organisation reported more than 200 cases of cholera.
While it is clear that climate change is adversely affecting all four dimensions of food security, much remains unknown about the extent to which climate change will interfere with global food security. To achieve a more holistic understanding on this, more evidence on the potential impacts of climate change on food stability, utilisation and access is necessary. Despite this, it is unequivocal that the impacts of climate change will fall disproportionately on the poor, particularly in sub-Saharan Africa and Southern Asia. The magnitude of these impacts will ultimately depend on policy. Frictionless trade with developing nations to enhance their access to international food supplies, investments in irrigation and sanitation infrastructure and commitments to reduce carbon emissions are all policies that would facilitate our ability to feed a warming world.