Climate change weighs heavily on cereal crops as scientists probe impact

28 Nov 2023 --- Scientists investigating the aftermath of acute climate change on cereal crops have highlighted 7% to 23% crop yield losses in the absence of adaptive measures. These findings come from an analysis of the impact of temperature spikes, high CO2 and water availability on staples like wheat, maize, millet, sorghum and rice.

The research was conducted at the Leibniz Centre for Agricultural Landscape Research (ZALF), Germany, with the findings published in Nature Reviews Earth & Environment.

Drought analysis
During the study, C3 crops like wheat and rice exposed to high levels of CO2 exhibited a compensatory effect on crop yield. But this was offset by heat and drought. 

On the contrary, elevated CO2 only benefits C4 plants such as maize, millet and sorghum under drought stress.

At higher latitudes, the adverse effects could be nullified or reversed by CO2 fertilization and adaptation options.

The scientists suggest adaptation techniques like irrigation to raise the wheat yields at higher latitudes.But, the authors note that lower latitudes’ primary crops are C4 crops, which show no appreciable benefits from CO2 fertilization. 

Besides drought, climate change has also led to devastating cyclones in Southern Africa and torrential rains in Nigeria, Niger and Sudan, which have created havoc and destroyed agricultural fields.

Adaptive measures
The researchers suggest adaptation techniques, including irrigation and nutrient management, to raise the wheat yields at higher latitudes by up to 40% compared with baseline. 

But, weighty financing and non-practicality in areas with water resource constraints pose roadblocks.

Meanwhile, the study cites multifactor experiments such as multipurpose cultivar panels, developing biotic stress modeling routines, merging process-based and data-driven models and using integrated impact assessments to examine crop yield responses to climate change better.

A vulnerable sector
The FAO flags that agriculture is one of the most highly exposed and vulnerable sectors when it comes to climate change and disaster risks, owing to its profound dependence on natural resources and climate conditions.

For instance, losses in cereals amounted to an average of 69 million tons per year in the last three decades — corresponding to the entire cereal production of France in 2021.

Other crops facing climate change blows include cocoa and coffee, whose pollinator count is threatened by erratic rain patterns and extreme heat.

Further, a decline in the yield and quality of hops due to hot and dry summers is making beer less flavorful. 

Amid such challenges, the Doomsday Vault in Norway provides hope for future crop security, with 1.2 million seed samples stowed safely at −18°C. It has accepted contributions from gene banks for over 15 years and houses crops from 74 countries.

By Insha Naureen