How does climate change threaten global food production?
A farmer collects sorghum plant at his submerged red sorghum field after heavy rain in Kournari village, on the outskirts of Ndjamena, Chad October 26, 2022. REUTERS/Mahamat Ramadan
As the planet heats, food security is weakening and the threat of hunger is growing
Kai Kornhuber is an adjunct associate research scientist at the Lamont Doherty Earth Observatory at Columbia University and a senior research fellow at the German Council on Foreign Relations. Corey Lesk is a postdoctoral climate researcher in the Department of Geography and the Neukom Institute at Dartmouth College.
In recent years, record-breaking heatwaves, droughts, and floods are becoming increasingly common across the globe. These extreme weather events impact supply chains, built infrastructure, people’s livelihoods - and food production.
Over the last decades, the world has experienced many episodes of crop production shortfalls in major cropping areas, regions known as ‘breadbaskets’.
But because many global staple crops are widely traded, a good harvest in one region can balance a poor harvest in another. This keeps global food prices stable and ensures that large parts of the world can have access to sufficient amounts of nutritious and affordable food.
However, a growing body of scientific research is showing that as the planet warms, the likelihood of extreme weather events hitting multiple breadbaskets at once is increasing, a situation that would have cascading effects felt across the globe.
This presents a very important challenge to the global food system, especially when combined with other global crises.
A summer of weather extremes
In 2022, we caught a glimpse of what a scattering of simultaneous weather extremes across global breadbaskets could look like.
Persistent extreme heat and drought dominated weather conditions in large parts of the northern hemisphere throughout the summer. A soggy spring delayed planting across much of North America’s croplands. Then, temperature records were smashed in North America, Western Europe, South Asia, and China, destroying crops or reducing their yields.
East Africa entered its fourth consecutive drought year, threatening millions of people with famine. Europe and China saw rivers wither and soils dry under extreme droughts, with consequences for food transport. And relentless heavy rains caused severe flooding in Nigeria and the US corn belt, and submerged a large portion of Pakistan’s rice crop.
In addition to their often record-breaking nature, the 2022 weather extremes consistently affected several regions at once, a feature that is becoming more common in the last decades, according to recent research.
The global geopolitical situation also contributes to the mix. High prices of farmer inputs due to global inflation in the aftermath of COVID-19 compounded with grain and fertilizer export disruptions due to the Russian invasion of Ukraine - both of which are major agricultural exporters.
Considering this ‘summer of extremes’, the 2022 global harvest may have dodged a bullet. Total crop production is set to decline by only 1.4% in 2022 compared to 2021, with strong harvests in some breadbaskets partly balancing severe losses in others.
But with 2022 global food prices at record levels, this shortfall will still contribute to local food crises.
The increasing risk of climate change
With climate warming, simultaneous extreme weather events across multiple breadbaskets are expected to become more common. This change can occur by mere chance: more extreme events happening globally can simply raise the odds of them impacting crops in multiple breadbaskets at once.
But other climate mechanisms can further boost these odds. Wavy patterns in the jetstream, an air current found in polar and subtropical regions, are linked to simultaneous heatwaves and yield losses across multiple breadbaskets.
When one such pattern occurs for two or more weeks in a summer, yields tend to drop by 4% across central North America, Eastern Europe and East Asia.
Another example is the El Niño-Southern Oscillation, in which periodic warming of the Pacific Ocean causes droughts, floods, and heatwaves in specific regions around the world.
The 1983 El Niño event caused the worst multiple-breadbasket crop failure on record, with simultaneous maize yield losses of 10-50% in Brazil, the United States, and southern and western Africa.
It is still not clear how climate change could influence these mechanisms, but recent studies have found that current climate models might be underestimating their importance in generating extreme events, meaning the real risks might be higher than currently projected.
For example, recent extreme weather events such as the 2021 Pacific Northwest heatwave and the 2021 Central European floods lay at the edge of what climate models said was possible.
These events suggest extreme weather could accelerate with continued warming at an even faster rate than previously estimated.
The world’s land areas have warmed by about 1.8 degrees Celsius on average since pre-industrial times. Crops are already experiencing higher background heat and drought stress, rendering them more susceptible to yield losses when global patterns of weather extremes do occur.
A new food system in an era of multi-crises
The global food system operates uncomfortably between multiple ongoing crises facing the world, of which climate warming is only one.
Geopolitical tensions, in particular following the Russian invasion of Ukraine, have weakened collaboration between countries on food reforms, and economic reactions to COVID-19 have increased inflation and disrupted supply chains.
Also, hunger is on the rise. After falling steadily since the 1960s, global undernourishment rates have risen every year since 2018 by a total of 2%.
These crises affect the stability of the global food network to accommodate climate shocks, which are inevitably going to increase in the coming decade. Other global trends might contribute to food system vulnerability.
Rising meat consumption, for example, will strain food supply, because every calorie of grain fed to an animal generates only a fraction of a calorie of food for people.
Next to increasing efforts to mitigate greenhouse gas emissions to prevent extremes to rise beyond adaptation capacities, there are some obvious interventions that can help our food systems to become more resistant to simultaneous climate shocks.
One of them is to invest more effort in international collaborations. Policies on food trade and stocks need to be reconsidered for a world at a higher risk from simultaneous crop losses. It is also necessary to strengthen the food storage and trade networks to reduce the risk, as well as to create better conditions for emergency food relief.
Such cooperation could bring countries together at a time of increasing factionalism. But the right balance must be struck between regionalism and globalism.
On the local level, many countries may benefit from greater food self-sufficiency. Decades of neoliberal policies have made large parts of the world dependent on food imports and more at the mercy of climate extremes and global price spikes.
Most fundamentally, the food system needs to adapt as a whole to climate change. New and improved crop varieties and ways of farming can help, especially if they consider the needs of more vulnerable smallholders that tend to be overlooked by major crop breeding companies.
But with the rising likelihood of concurrent weather extremes, local farming adaptation is only half the solution. If the balance between good and bad harvests can no longer be taken for granted, a wide portfolio of complementary global food system adaptations will be needed to maintain a stable food supply.
Achieving this goal will require cooperation among a slew of actors like governments, international agencies, not-for-profits, farmers organizations, academic researchers, and agrifood companies. That cooperation will be a challenge, but global food stability is in everyone’s interest.
Any views expressed in this opinion piece are those of the author and not of Context or the Thomson Reuters Foundation.
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