Together We Can Defend against Climate Threats to Food Safety
While climate threats to global food security and projections of worsening hunger tend to grab headlines, climate threats to food safety are less publicized and less well understood, but remain just as serious. After all, if food isn’t safe then it isn’t food. Yet, countering these threats to food safety will not be simple, given the deep complexity of the climate crisis and the many ways its impacts will be felt.
USAID’s Climate Strategy 2022-2030 gives an overview of this multitude of threats to human health with its graphical representation of the impacts of climate change. Among these dire predictions are the seeds of hope — clues to how we can proactively protect the safety of our world’s food.
Threats on the Horizon
Prominent among climate threats to food safety is a nemesis already well known to the food safety community: foodborne pathogens. Of the approximately 600 million cases of foodborne illness estimated worldwide in 2010, 550 million are attributed to diarrheal diseases caused by infectious pathogens, such as Campylobacter spp., Vibrio cholerae, Shigella spp. and Escherichia coli. Rising temperatures — depicted in USAID’s Climate Strategy graphic as the “heat” impact — provide favorable conditions for these pathogens to grow and reproduce quickly, leading to greater disease incidence in both low- and high-income countries. For instance, studies have shown that each 1 degree Celsius increase in temperature results in 8% greater incidence of diarrheal disease in Peru, 5% more reported cases of Campylobacter enteritis in England, 5-10% increase in salmonellosis cases in multiple European countries and 40% greater incidence of diarrhea associated with rotavirus in Dhaka, Bangladesh, with similar associations demonstrated for many more foodborne pathogens.
Climate change is also increasing the threat of foodborne pathogens through a multitude of indirect means. Rising temperatures and changes in precipitation patterns can favor greater activity in insects that carry pathogens, such as flies and cockroaches. These impacts on temperatures and weather can also pose indirect threats to food safety by increasing the susceptibility of livestock to zoonotic disease and increasing the range and abundance of the vectors that transmit them. Heat stress can increase shedding of enteric pathogens in livestock, as has been reported with Shiga toxin-producing E. coli in cattle herds in Michigan. The extreme rainfall and other severe weather depicted in the USAID Climate Strategy graphic can increase risks associated with foodborne diseases through contamination of farmland with waterborne pathogens, disruptions of food transportation that give pathogens more time to grow, power outages that compromise cold chains and storage and damage to food storage facilities. Water scarcity, another outcome of climate change noted in the USAID Climate Strategy, can compromise hygienic conditions in food processing plants and households.
Algal blooms are another threat to food safety exacerbated by climate change, through increases in phycotoxins in seafood that cause ciguatera poisoning and other toxic syndromes. Though algal blooms are the consequence of multiple factors, including some less directly tied to climate change, such as eutrophication from agricultural runoff and ecological disruption from overfishing, climate change is still contributing to a rise in incidence, intensity and geographic spread of algal blooms through rising ocean temperatures, ocean acidification and extreme weather events that carry nutrients from watersheds or the deep sea into coastal waters.
Another threat is mycotoxins, which are produced by fungi that can grow in or on all of the world’s major cereal and oilseed crops and can cause cancer or exert other toxic effects on the body’s renal, reproductive, immune and gastrointestinal systems. Aflatoxins, a type of mycotoxin, are anticipated to become a more significant food safety threat in maize and wheat in Europe due to increasing temperatures expanding the range of toxigenic fungi and crop pests that can carry fungal spores or induce plant stress that increase susceptibility to fungal infections. Furthermore, drought-induced plant stress increases susceptibility to fungal infections and flooding from changing rainfall patterns and extreme weather events can lead to prolonged moisture and plant stress that favor mycotoxin production.
Beyond microorganisms, heavy metal contamination may become a greater food safety concern due to climate change impacts. Climate change-driven changes in rainfall patterns are predicted to increase the leaching of heavy metals into water systems and may be compounded when melting permafrost releases long-trapped heavy metals into aquatic ecosystems. Rice, in particular, is known to take up and bioaccumulate the heavy metal arsenic, and this process has been observed to increase with elevated soil temperatures and higher air temperatures. Greater mercury bioaccumulation in seafood has been associated with increases in ocean temperatures and with ocean acidification.
Rising to the Challenge
These climate threats to food safety are far from exhaustive. Yet, there is hope, as much remains to be done to strengthen our defenses against food safety threats.
Crucial to the fight against food safety threats are tools that are already being utilized with a strong track record of success when implemented well: robust data collection, monitoring and surveillance of food safety threats throughout food systems. These systems allow us to identify and stop threats in their tracks, and to triage outbreaks of foodborne pathogens and contaminants that do occur so we can learn how to prevent them in the future. Investments in data collection and research are needed to further build our understanding of how climate change is impacting food safety, including threats that have yet to be identified.
Key to establishing and strengthening data systems is raising the profile of the importance of food safety across a broad range of stakeholders. Food is essential to us all, and the safety of the world’s food supply should rightfully be valued by all, regardless of where food safety threats are coming from. This means rallying political will across all levels of local and national governments and strengthening cooperation between country governments to prioritize food safety in regional trade policy development and implementation. The first joint Food and Agriculture Organization (FAO), World Health Organization (WHO) and African Union (AU) International Food Safety Conference in 2019, as well as the drafting of the WHO Global Strategy for Food Safety 2022-2030, are promising steps toward greater international coordination.
Additionally, local food producers and the broader private sector are key allies in the fight to protect food. USAID has reaffirmed its commitment to localization and prioritization of locally led partnerships, and for good reason. Farms and fisheries are where the journey of food begins, and where many food safety threats can be prevented. Given the preeminence of the private sector in all aspects of food systems, private sector firms throughout food systems are well positioned both to support identification of vulnerabilities to food safety threats, and to develop and implement measures needed to control them. Everyone stands to benefit from closer collaboration between academic institutions, governments, health care providers and the private sector to achieve food safety goals. Ultimately, food safety is just good business.
The challenges that climate change poses to safeguarding the world’s supply of safe, nutritious food are indeed significant. Yet, they are not insurmountable, and by working together, we can effectively defend against these threats.