The 2018 South African Degrees Modelling Fund team has published a new book chapter with Temitope Egbebiyi as the lead author. The chapter models the impacts of both climate change and solar radiation modification (SRM) on cocoa production in Nigeria.
Cocoa production in Nigeria is primarily concentrated in southern regions, and the country is one of the world’s top four producers worldwide. It has become a “cornerstone of Nigeria’s agricultural sector, providing a livelihood for millions of smallholder farmers and supporting numerous downstream industries”. With climate change posing “a severe threat to Cocoa cultivation, impacting its suitability and potentially hampering Cocoa dependent economies”, the team set out to find out more about SRM’s potential effects.
The study uses an SRM scenario that offsets future global warming by modelling a global layer of reflective particles that produces an even pattern of cooling. They compared this scenario against an extreme scenario of future greenhouse gas emissions where, rather than falling, emissions continue accelerating into the future, leading to intense global warming.
The researchers found that SRM could effectively counter the rise in temperatures projected to happen as a result of climate change. They also concluded that, when used to counteract an extreme global warming scenario, SRM could reduce monthly rainfall, with the greatest impact in southern Nigeria. Their results suggest that climate change under a high emissions scenario would reduce the amount of land that is suitable for cocoa production and that SRM would not be able to reverse this trend entirely. While the team found that, relative to the climate change scenario, SRM would increase the area most suitable for cocoa production, it would increase the fraction of the area that was entirely unsuitable for cocoa production.
The team highlighted the limitations of the SRM scenario they used and recommended that future studies use a wider range of scenarios, rather than the extreme one used in this study. Similarly, they noted the simplicity of the crop model used here and suggested that future studies could use models that account for a broader range of variables affecting crop production. While this study is the first of its kind in this region, they encouraged future research to model the impact of climate and SRM on different crop types.
Potential Impact of Stratospheric Aerosol Geoengineering on Cocoa Suitability in Nigeria by Temitope Egbebiyi, Christopher Lennard, Pinto Izidine, Romaric Odoulami, Piotr Wiolski and Akintunde Makinde in Shifting Frontiers of Theobroma cacao – Opportunities and Challenges for Production edited by Samuel Agele and Olufemi Ibiremo (2023).