Multiple breadbasket failure
Multiple Breadbasket Failure (MBBF) occurs when several major farming regions, known as 'breadbaskets', experience large-scale crop failures simultaneously. These regions, such as key grain-growing regions or agricultural hubs, are critical for global food production and their simultaneous failure would pose a serious global risk.
Global warming driven by human activities increases the likelihood of severe weather events happening at the same time across these key farming areas. This would greatly reduce crop yields, lead to sharp rises in food prices, and worsen global food insecurity. An ASRS (from e.g. nuclear war or volcanic eruption) or GCIL (from e.g. nuclear EMP or cyberattack) could also result in an MBBF.
Abrupt sunlight reduction
Several catastrophes threaten to devastate agricultural production by causing global temperature, sunlight, and precipitation to quickly plummet.
Asteroid impact
The Chicxulub asteroid impact, which occurred approximately 66 million years ago, is perhaps the most famous global cooling event as it may have caused the extinction of the dinosaurs. During asteroid impact events, like Chicxulub, ash and soot would loft into the stratosphere, reducing the sunlight reaching Earth’s surface for up to 10 years.
Volcanic eruptions
The largest volcanic eruptions on the Volcanic Explosivity Index (VEI), the VEI 7s and greater have, in the past, caused abrupt climate change and may have caused the collapse of civilizations, and have been associated with the rise of pandemics. One of the largest known eruptions to impact humans was the most recent supervolcanic eruption of the Toba Caldera Complex, which occurred about 74,000 years ago. Eruptions with a VEI 7 or higher have a chance of occurrence of around 1 in 6 per century.
The VEI 7 eruption of Mount Tambora in Indonesia, in 1815, triggered what would become known as the Year Without a Summer, in 1816. Temperatures plummeted globally, disrupting the monsoon season in Asia for three consecutive years and reducing food production around the world. Food shortages, along with riots, looting, violence, and increased vulnerability to disease, were recorded across Asia, Europe, and North America. In more recent memory, the 1991 VEI 6 eruption of Mount Pinatubo was 10 times smaller than the Mount Tambora eruption, but still had a measurable global cooling impact.
Nuclear winter
However, many risk and threat analysts say that the most likely cause of abrupt global cooling in the near future may be a nuclear war.
Nuclear attacks on cities could loft large amounts of soot into the stratosphere where they could become entrapped for years, reducing the sunlight reaching the surface of the Earth. Climate models show that a regional nuclear war between India and Pakistan, involving approximately 100 nuclear weapons, could reduce sunlight enough to decrease temperatures by up to 1.5 °C (3 °F) for a few years. Previous work by Physicians for Social Responsibility anticipates that the loss of food resulting from such a scenario could leave one to two billion people without sufficient access to food.
While India and Pakistan currently have comparatively small nuclear arsenals, the United States and Russia each have thousands of nuclear weapons. A large nuclear war between these nations could cause a nuclear winter, in which average global cropland temperatures could drop by up to 10 to 16 °C (18 to 29 °F) for half a decade, and could take more than a decade to fully recover. The direct destruction from the nuclear weapons would be horrific, but the resulting global winter could cause food production to collapse, and this disruption in food supply could put billions of lives at risk.
Agronomic catastrophes
We refer to catastrophes affecting plant health directly as “agronomic catastrophes.” These could include a superweed, super crop disease, super crop pest, a mass die-off of microorganisms that benefit plants, or rapid pollinator loss (e.g., of bees).
Some agronomic catastrophes could occur via a mutation that spreads quickly or via an accidental human introduction, but one of the more catastrophic ways that they could occur might be a terrorist attack or large scale warfare. Unless an agronomic catastrophe was triggered intentionally, it’s unlikely that any of these would occur at a global level. However, depending on where it occurred, it could still spread widely enough to impact some of the world’s large breadbaskets.
Extreme weather events across multiple continents
One of the risks we face over the next few decades is extreme weather events that could impact agriculture, especially in breadbasket regions of the world. Protracted or repeated droughts, major heat waves, floods, and wildfires could all damage or destroy crops, which would significantly reduce food production and distribution.
A United Kingdom government study predicts an 80% likelihood that a combination of extreme weather events could trigger a 10% global agricultural shortfall within this century. This may seem very high, but it’s based on a simple compounding of a low annual risk—the chance of a minor traffic accident on your street is low on any given day, but high in your lifetime. Ideally, we want to prevent or avoid threats from materializing, but since that’s not guaranteed, it is also necessary to work on mitigating the impacts of the catastrophe to enable an easier recovery.
Even with food shortages that don’t reach the scale of a global catastrophic risk (GCR), many of the solutions ALLFED advocates for could still be useful in national disasters or isolated regions.