Researchers zero in on critical threshold of CO2 and crop yield

It’s clear that human activities such as transportation and energy production are causing atmospheric carbon dioxide (CO2) levels to rise, which increases the global average surface temperature — and poses a threat to crop growth. Escalating concerns about climate change’s impact on global food security inspired researchers to create a way to explore how these factors influence crop yields.

In Chaos: An Interdisciplinary Journal of Nonlinear Science, these researchers share a mathematical model created to capture the nonlinear dynamics of atmospheric CO2, rising temperatures, human population, and crop growth. Increasing evidence of chaotic and complex dynamics within ecological systems led them to use both autonomous and nonautonomous models to gain a deeper understanding of seasonal variations and potential mitigation strategies, such as developing temperature-tolerant crops.

“We’ve considered how the rising CO2 levels will initially boost crop growth through the ‘CO2 fertilization effect,’ but once temperatures exceed a critical threshold the heat stress will reduce yields,” said A.K. Misra, a researcher at Banaras Hindu University. “A nonautonomous system with seasonal variations reveals complex behaviors like periodic oscillations and chaos—and highlights the unpredictability of crop responses to rising temperatures.”

The concepts considered by the team are central to understanding the complexity of climate and crop interactions that may lead to unexpected extreme outcomes. Their work shows the importance of managing these variables effectively to sustain agricultural productivity.

“Our findings reveal a critical threshold for anthropogenic CO2 emission, beyond which crop yield starts to decrease significantly,” said Misra, who’s article was titled, article Impact of elevated carbon dioxide and temperature on crop yield: A study of autonomous and nonautonomous systems. “It depends on the cultivated crop varieties — different varieties exhibit varying responses, so the results may not apply uniformly across all crops.”

The team’s work highlights the urgent need to address CO2 emissions to maintain agricultural productivity. Globally, fossil fuel use is the primary source of CO2, but the gas can also be emitted from the landscape through deforestation or land clearance for agriculture or development.

Yet the team did point toward a promising strategy to mitigate crop loss caused by climate change: developing crop varieties with a higher temperature tolerance.

By breeding or engineering crops to withstand elevated temperature, farmers can better adapt to changing environmental conditions to protect the crop yield. This adaptability is especially crucial in the face of global warming — making climate-resistant agriculture a key factor in ensuring food security. One surprising takeaway from the study is the extent to which relatively small increases in temperature may impact crop yields.

This work has applications for agriculture in the face of climate change.

“By identifying critical temperature thresholds, we get insights into when crop yields may begin to decline, which will guide policymakers in making more beneficial strategies,” said Misra. “Our findings suggest breeding or using crops with increased temperature tolerance should be considered as a strategy to maintain productivity under elevated CO2 levels.”

Understanding the chaotic behavior of crop systems helps to improve yield predictions and inform adaptive farming practices for managing seasonal and climatic variability.

Next steps for the team involve refining their model to include more variables like insect population, water availability, soil quality, and nutrient levels, which also impact crop yield under climate change.