Climate change is one of the major challenges of the 21st century. It is a growing threat to our food systems, with impacts becoming increasingly evident. Rising temperatures, changing precipitation patterns, and extreme weather events, among other effects, are already reducing agricultural yields and disrupting food supply chains. By 2050, climate change is expected to put millions of people at risk of hunger, malnutrition, and poverty.

Global food production needs to be doubled by 50% by the middle of the 21st century to ensure the food and nutritional security for 9 billion people explicitly in challenging scenarios such as land degradation, water scarcity and environmental pollution. Climate change is evident worldwide due to the exponential rise in atmospheric carbon dioxide and temperature. It leads to more complexity in achieving sustainable food security.

Higher temperatures, changing precipitation patterns, sea level rise, and growing frequency and intensity of extreme weather events such as droughts, floods, extreme heat, and cyclones are already reducing agricultural productivity, disrupting food supply chains, and displacing communities. At the same time, food systems are estimated to contribute more than a third of the global greenhouse gas (GHG) emissions responsible for climate change, placing food production at the center of attention as both a contributor to global warming and a critical sector for mounting an adaptive response to climate change.

Climate change will increasingly put pressure on food production and access, especially in vulnerable regions, undermining food security and nutrition. Increases in frequency, intensity and severity of droughts, floods and heatwaves, and continued sea level rise will increase risks to food security in vulnerable regions from moderate to high between 1.5°C and 2°C global warming level, with no or low levels of adaptation. At 2°C or higher global warming level in the mid-term, food security risks due to climate change will be more severe, leading to malnutrition and micro-nutrient deficiencies, concentrated in Sub-Saharan Africa, South Asia, Central and South America and Small Islands. Global warming will progressively weaken soil health and ecosystem services such as pollination, increase pressure from pests and diseases, and reduce marine animal biomass, undermining food productivity in many regions on land and in the ocean. At 3°C or higher global warming level in the long term, areas exposed to climate-related hazards will expand substantially compared with 2°C or lower global warming level, exacerbating regional disparity in food security risks.

In the scenarios the Intergovernmental Panel on Climate Change (IPCC) assessed, limiting warming to around 1.5°C requires global greenhouse gas emissions to peak before 2025 at the latest, and be reduced by 43% by 2030; at the same time, methane would also need to be reduced by about a third. Even if we do this, it is almost inevitable that we will temporarily exceed this temperature threshold but could return to below it by the end of the century.

“It’s now or never, if we want to limit global warming to 1.5°C,” said IPCC Working Group III Co-Chair Jim Skea. “Without immediate and deep emissions reductions across all sectors, it will be impossible.”

The global temperature will stabilize when carbon dioxide emissions reach net zero. For 1.5°C, this means achieving net zero carbon dioxide emissions globally in the early 2050s; for 2°C, it is in the early 2070s. This assessment shows that limiting warming to around 2°C still requires global greenhouse gas emissions to peak before 2025 at the latest, and be reduced by a quarter by 2030.

Looking forward, modeling scenarios, created by researchers at the International Food Policy Research Institute (IFPRI) together with other CGIAR colleagues, indicate that rising temperatures will negatively impact agricultural yields, driving up prices and resulting in increased hunger, especially in Africa. The goal of ending hunger will remain elusive even by 2050, especially considering the additional impacts of extreme weather events, local shocks, and global crises, such as COVID-19 and the current war in Ukraine, that will push many more people into poverty and hunger. Thus, beyond its direct impacts on production, climate change will create cascading effects on livelihoods and sustainability through interconnections among economic, environmental, social, and political spheres.

Agriculture is one of the most exposed sectors to climate change, both over the short-term, as extreme weather events increase in frequency and severity, and the long-term, due to broader shifts in climatic patterns including temperature and precipitation. Notably, these adverse effects not only impact farmers whose livelihoods depend on crop yields, but also the complex network of actors who then depend on those agricultural products for food security or as inputs to other economic activities. In a globalizing world, much of the food we eat – as well as the feed and other inputs which become the food we eat – is produced significant distances from where it is consumed; before arriving on supermarket shelves it is traded on international markets and travels through global supply chains. In this way, achieving global food security involves a broad range of interdependent activities all around the world, including the stability of markets, which allows food to be purchased at affordable prices.

CLIMATE RISKS TO STAPLE CROPS

Since agriculture began approximately 10,000 years ago, grains have provided the main source of calories for the human diet. Recognized for their high yields, nutritional value, and ease of transport and storage, a range of different grains were domesticated by the world’s original farmers. Wheat, rice, maize, barley, sorghum, millet, and root crops still constitute the basis of human nutrition worldwide.

Staple crops maize, rice and wheat are consumed worldwide as an integral part of the daily diet of billions of people. Changes in the price and availability of these commodities directly affect peoples’ food and nutritional security. Changes in commodity prices are easy to track and rapidly and directly influence the price consumers pay at market. These staple crops tend to be produced via heavily mechanized commercial agriculture and traded on global markets. Climate risks to these commodities are therefore a matter of international and national government policy, national security and high politics.

CLIMATE CHANGE IMPACT ON CROPS EXPECTED WITHIN 10 YEARS

Climate change may affect the production of corn and wheat as early as 2030 under a high greenhouse gas emissions scenario, according to a NASA study published in the journal, Nature Food. Corn crop yields are projected to decline 24%, while wheat could potentially see a growth of about 17%.

Using advanced climate and agricultural models, scientists found that the change in yields is due to projected increases in temperature, shifts in rainfall patterns, and elevated surface carbon dioxide concentrations from human-caused greenhouse gas emissions. These changes would make it more difficult to grow corn in the tropics, but could expand wheat’s growing range.

“We did not expect to see such a fundamental shift, as compared to crop yield projections from the previous generation of climate and crop models conducted in 2014,” said lead author Jonas Jägermeyr, a crop modeler and climate scientist at NASA’s Goddard Institute for Space Studies (GISS) and The Earth Institute at Columbia University in New York City. The projected corn response was surprisingly large and negative, he said. “A 20% decrease from current production levels could have severe implications worldwide.”

To arrive at their projections, the research team used two sets of models. First, they used climate model simulations from the international Climate Model Intercomparison Project-Phase 6 (CMIP6). Each of the five CMIP6 climate models used for this study runs its own unique response of Earth’s atmosphere to greenhouse gas emission scenarios through 2100. These responses differ somewhat due to variations in their representations of the Earth's climate system.

Then the research team used the climate model simulations as inputs for 12 state-of-the-art global crop models that are part of the Agricultural Model Intercomparison and Improvement Project (AgMIP), an international partnership coordinated by Columbia University. The crop models simulate on a large scale how crops grow and respond to environmental conditions such as temperature, rainfall and atmospheric carbon dioxide, which are provided by the climate models. Each crop species’ behavior is based on their real life biological responses studied in indoor and outdoor lab experiments. In the end, the team created about 240 global climate-crop model simulations for each crop. By using multiple climate and crop models in various combinations, the researchers were more confident in their results.

“What we're doing is driving crop simulations that are effectively growing virtual crops day-by-day, powered by a supercomputer, and then looking at the year-by-year and decade-by-decade change in each location of the world,” said Alex Ruane, co-director of the GISS Climate Impacts Group and a co-author of the study.

The team looked at changes to long-term average crop yields and introduced a new estimate for when climate change impacts “emerge” as a discernable signal from the usual, historically known variability in crop yields. Soybean and rice projections showed a decline in some regions but at the global scale the different models still disagree on the overall impacts from climate change. For corn and wheat, the climate effect was much clearer, with most of the model results pointing in the same direction.

Corn is grown all over the world, and large quantities are produced in countries nearer the equator. North and Central America, West Africa, Central Asia, Brazil, and China will potentially see their corn yields decline in the coming years and beyond as average temperatures rise across these breadbasket regions, putting more stress on the plants.

Wheat, which grows best in temperate climates, may see a broader area where it can be grown as temperatures rise, including the Northern United States and Canada, North China Plains, Central Asia, Southern Australia, and East Africa, but these gains may level off mid-century.

Temperature is not the only factor the models consider when simulating future crop yields. Higher levels of carbon dioxide in the atmosphere have a positive effect on photosynthesis and water retention, increasing crop yields, though often at a cost to nutrition. This effect happens more so for wheat than corn, which is more accurately captured in the current generation of models. Rising global temperatures also are linked with changes in rainfall patterns, and the frequency and duration of heat waves and droughts, which can affect crop health and productivity. Higher temperatures also affect the length of growing seasons and accelerate crop maturity.

“You can think of plants as collecting sunlight over the course of the growing season,” said Ruane. “They're collecting that energy and then putting it into the plant and the grain. So, if you rush through your growth stages, by the end of the season, you just haven't collected as much energy.” As a result, the plant produces less total grain than it would with a longer development period. “By growing faster, your yield actually goes down.”

“Even under optimistic climate change scenarios, where societies enact ambitious efforts to limit global temperature rise, global agriculture is facing a new climate reality,” Jägermeyr said. “And with the interconnectedness of the global food system, impacts in even one region’s breadbasket will be felt worldwide.”

Recognizing that corn, rice and wheat play a critical role in achieving global food security, climate change not only creates risks for producing countries but also transmits those risks through agricultural commodity trade to consumers of all kinds, and can do so over significant distances. The corn and rice markets appear to be highly exposed to climate change, and while wheat production seems more stable, the cost of redistributing wheat production to Europe and parts of South America and Asia needs to be taken into account and would likely entail significant negative consequences for existing producers.

Ensuring that everyone has access to — and consumes — sustainable healthy diets is one of the most significant challenges for today’s food systems. Climate change is expected to adversely affect diets, nutrition, and health through impacts on the quantity, quality (nutrient content), diversity, safety, and affordability of produced food. Production constraints, in turn, will continue to cause the loss of livelihoods, income, and food security for food producers, processors, and their families and will jeopardize their diets, nutrition, and health. Combined with the impacts of climate change on disease patterns, these effects will continue to disproportionately impact marginalized populations in low- and middle-income countries (LMICs), including those with the least access to resources and tools for adaptation. Shifts toward healthy diets must therefore focus on the dual goals of protecting and improving the nutrition and health of populations while also meeting environmental goals in an equitable way.

IMPLICATIONS OF CLIMATE CHANGE FOR AGRI-FOOD VALUE CHAINS

Climate change will drive responses and adaptations throughout agrifood systems. Changes in growing conditions for many crops will alter agricultural production patterns. Along with these shifts in crop production, rising temperatures, changes in humidity levels, and increased extreme weather will also affect the value chains through which agricultural products are traded, aggregated, processed, and sold to consumers.

Climate change can be expected to reshape agrifood value chains in three ways: through gradual changes; through the increased likelihood of shocks; and through increased potential for conflict. While crop production is most obviously affected by climate change, risks of postharvest losses will increase and incentives for finance and insurance providers will also change. Threats to livelihoods and food security increase the risk of civil strife and conflict, which can disrupt whole value chains. Consumers may add to the pressures for change across entire value chains not only through changes in diets but also through demand for sustainably produced products. All these changes have implications for value chain actors from smallholders to urban consumers.

Agrifood value chains must adapt to climate change. Value chains offer less potential to help mitigate climate change, however. Despite the growing complexity of some value chains, evidence on greenhouse gas emissions suggests that the value chain steps between production and consumption — including processing and transporting agricultural products to end markets — only account for 18–29 percent of total emissions from agri-food systems, even for products traded over long distances. Since this range represents a total over a wide range of products and levels of value chain complexity, there are no easy fixes for reducing those emissions. For example, research suggests that “buy local” movements will not materially reduce emissions, and instead might increase them, as there are returns to scale in moving bulky agricultural products. Even effective interventions to reduce emissions between farms and retailers may have little overall effect.

As our climate changes, agrifood value chains must adapt to new cropping patterns and changes in investment and input needs. Governments must safeguard against the risk of increasing food and nutrition insecurity, and agrifood value chains must be transformed to address climate security concerns. In the short term, policymakers can focus on ways to reduce food loss and waste in value chains, particularly for perishables, to yield more food from their agri-food systems and potentially to alleviate the local environmental stress associated with food systems development. In the medium term, investments in climate-smart infrastructure, including new roads and electrification to support the development of cold chains, will be important to safeguard food and nutrition security. To ensure that civil strife and conflict are not fostered by climate change, investments will be needed not only in monitoring but also in ensuring that smallholders and other vulnerable value chain actors can adapt and that both diets and livelihoods are protected and improved.

POTENTIAL OF DIGITAL INNOVATIONS TO MANAGE CLIMATE RISKS

While global warming is a threat to food systems, there are unprecedented opportunities for technological solutions to contribute to climate change mitigation and adaptation in food production. Digital tools already provide food producers with timely insights and services that support improvements in agricultural productivity and profitability. Across low- and middle-income countries (LMICs), the number of digital agricultural services (such as digital advisory services, digital procurement, e-commerce, digital finance, and smart farming services) increased rapidly during the past decade, from 53 reported in 2009 to 713 in 2019, with beneficial impacts. In sub-Saharan Africa, for example, meta-analysis studies show that producers who adopted digital extension and financial services increased their incomes by 20 to 40 percent and their adoption of recommended agrochemical inputs by 22 percent.

Digital technologies can be a particularly powerful, innovative tool for managing climate risks across food systems — from producers to markets and value-chain services to policymakers. As weather patterns become more variable at the farm level, producers can use digital technologies to access localized weather and climate information services in order to optimize farm management decisions, such as irrigation scheduling and crop variety selection. Digital extension services help small-scale producers to communicate with experts, who can diagnose farm-specific problems and prescribe best-bet climate-smart practices. Weather index-based crop and livestock insurance schemes, which assess climate-induced losses remotely and provide payouts through digital financial services, offer producers an increasingly important option for managing climate risk. By using data from mobile phones and satellite remote-sensing, these digitally enabled insurance products can estimate agricultural losses faster and at a lower cost and can make timely payouts for losses.

All along food supply chains, the postharvest use of internet-connected smart sensors, such as time-temperature indicators (TTIs) and tech-enabled traceability devices, allow value-chain actors to detect potential food safety and quality issues (such as the prolonged exposure of dairy products to high temperatures during transportation) and thus reduce health risks and postharvest losses. Digital innovations for value-chain services — financial services, credit, and insurance — can reduce transaction costs, address information asymmetries in traditional markets, and make crop insurance and digital finance more affordable and inclusive. For public sector agencies and government entities, real-time food systems that monitor data collected, analyzed, and disseminated using digital technologies can improve early warning systems and help policymakers to make informed decisions to prepare for and mitigate risks.

Digital innovations in forecasting can support climate science with information on weather, climate variability, and climate change, and can play a vital role in supporting food system resilience to worsening weather extremes. For example, every month, the European Centre for Medium-Range Weather Forecasts releases a seven-month global forecast of temperature and precipitation. These forecasts use advances in Earth-system monitoring and prediction modeling capabilities to extend conventional short-term weather forecasts (up to two weeks) to seasonal climate predictions. Enhanced weather and climate forecasting skills improve early detection and warning systems for floods and droughts. With this information, policymakers can prepare for disasters and reduce damages by, for example, declaring emergencies early and getting resources where they are likely to be needed in advance. Between 2000 and 2017, advances in flood early-warning systems were estimated to have already helped to reduce global flood-related human casualties by 45 percent and the number of people affected by floods by 24 percent. Conservative estimates based on a meta-analysis of global studies suggest that the benefit-cost ratio for reliable climate information services is about 10 to 1, with potential global benefits as high as US$30 billion per year in increased agricultural productivity and $2 billion per year in reduced asset losses.

Population growth, climate change, and unsustainable use of natural resources have made a negative impact on food security around the world. In the absence of a global commitment to build food systems adapted to climate change and ensure food security, while minimizing greenhouse gas emissions and sustaining our natural resource base, this negative impact is likely to increase.

Such drastic occurrences will lead to international food shortages and rising food prices in the coming decades, which will result in malnourishment and an increase in poverty increase in lesser developed regions. Expanded investments in sustainable agriculture to increase agricultural productivity per land area and to avoid losses in productive capacity, as well as promotion of healthier food diets and food waste reduction, are required to avoid an increasing gap between food supply and demand.

Climate change is a threat to human well-being and planetary health. Any further delay in concerted anticipatory global action on adaptation and mitigation will miss a brief and rapidly closing window of opportunity to secure a liveable and sustainable future for all.

REFERENCES:

International Food Policy Research Institute. 2022. 2022 Global Food Policy Report: Climate Change and Food Systems. Washington, DC: International Food Policy Research Institute. https://doi.org/10.2499/9780896294257

FAO. 2022. Crops and climate change impact briefs. Climate-smart agriculture for more sustainable, resilient, and equitable food systems. Rome. https://doi.org/10.4060/cb8030en

Adams, K.M., Benzie, M., Croft, S. & Sadowski, S. (2021). Climate Change, Trade, and Global Food Security: A Global Assessment of Transboundary Climate Risks in Agricultural Commodity Flows. SEI Report. Stockholm Environment Institute, Stockholm. https://doi.org/10.51414/sei2021.009