Climate Change

Modelling study shows how controversial geoengineering may affect global food production

Process includes injecting sulphur dioxide into atmosphere to reduce global temperatures; may lead to inequities in food production

By Rohini Krishnamurthy
Published: Friday 06 October 2023
Agricultural production in India may see an increase under large amounts of climate intervention. File photo: CSE_

Implementing a controversial climate intervention could likely create inequities in food production, benefitting some and harming others, a new study published in journal Nature Food warned.

The intervention proposed to counter climate change is a geoengineering technology called stratospheric aerosol intervention (SAI). It is often referred to as Plan B if mitigation strategies to reduce emissions fail.

SAI mimics volcanic eruptions by injecting sulphur dioxide into the stratosphere (layer of atmosphere extending from about 10 kilometres to 50 km in altitude), where it oxidises to form sulphuric acid, which then forms reflective aerosol particles. 

Read more: ‘We need to match frequency and intensity of climate disasters with bold, collective action’

For example, Mount Pinatubo in the Philippines erupted in 2001 and injected about 15 million tonnes of sulphur dioxide into the stratosphere, which then formed aerosol particles, according to National Aeronautics and Space Administration. It caused a drop in the average global temperature of about 0.6 degrees Celsius over the next 15 months.

Injections, according to the paper, would need to occur continuously to maintain decreased solar radiation and surface temperature.

This reduction of temperature brought about by SAI would affect agriculture in different ways in different locations and other climate factors important to agriculture, such as precipitation and solar radiation, Brendan Clark, a doctoral student at the Rutgers School of Environmental and Biological Sciences and lead author on the study, told Down To Earth.

“Understanding what global temperature is optimal to produce the most crops in each nation is important to inform future decision-makers,” he added. 

Clark and his colleagues used computer models to analyse the impacts on maize, rice, soybean and spring wheat production under different levels of SAI scenarios. They examined 11 scenarios.

Under continued uncontrolled climate change, crop production is favoured in cold, high-latitude areas such as Canada, Russia, the United States’ northern border states, Scandinavia and Scotland.

Read more: Climate finance needs could cost India 85.6 lakh crore by 2030

If the world opts for moderate amounts of atmospheric sulphur spraying, the temperate regions known as the mid-latitudes, like the land masses of North America and Eurasia, are likely to benefit from SAI by seeing an increase in food productivity, 

Under large amounts of climate intervention, agricultural production in the tropics could see an increase.

These regions include Mexico, Central America, the Caribbean and the top half of South America, most of Africa, parts of the Middle East, most of India, all of Southeast Asia, most of Australia and most of the island nations of Oceania.

“Some nations could maximise their agricultural production with moderate amounts of intervention, which would maintain 2.0°C above preindustrial, while other nations may prefer larger amounts of intervention to maintain 0.5°C above preindustrial to maximise crop production,” Clark explained.

Cold regions may prefer no climate intervention and may benefit from warming due to climate change for food production, he added.

More equatorial nations, on the other hand, may prefer large levels of climate intervention to reduce global temperatures to produce the most crops.

Read more: Benefits of climate adaptation far outweigh costs

“Are we willing to live with all these potential impacts to have less global warming? That’s the question we are trying to ask here,” Alan Robock, a Distinguished Professor of Climate Science in the Department of Environmental Sciences at SEBS and a co-author of the study, said in a statement. 

Clark explained that this study looked at one crop production impact of SAI. “But there are many impacts that would need to be considered. For example, impacts on human health and ecosystems from climate intervention have barely been studied. Further, he noted, the study did not consider any agricultural adaptation in this study. 

Read more:

Subscribe to Daily Newsletter :

Comments are moderated and will be published only after the site moderator’s approval. Please use a genuine email ID and provide your name. Selected comments may also be used in the ‘Letters’ section of the Down To Earth print edition.