Impact of Climate Change on Staple Crop Yields and the Role of Adaptation in Achieving Sustainable Development Goals

Introduction

A recent study published in Nature investigates the projected changes in yields of six staple crops—cassava, maize, rice, sorghum, soybean, and wheat—under two warming scenarios. The study uniquely incorporates adaptive measures farmers might employ to mitigate climate change impacts, aligning with the Sustainable Development Goals (SDGs), particularly SDG 2 (Zero Hunger) and SDG 13 (Climate Action).

Study Overview and Methodology

1. The study models crop yield impacts under two emissions scenarios:
   • Moderate emissions (RCP4.5)
   • Very high emissions (RCP8.5)
2. Two future timeframes are analyzed: 2050 and 2098.
3. Adaptive measures considered include switching crop varieties and adjusting irrigation.
4. Data from 12,658 sub-national regions were used to link yield changes to exposure to extreme heat days, reflecting real-world adaptation capacity.
5. Socioeconomic conditions were modeled using SSP3, representing a “rocky road” development pathway due to geopolitical tensions.

Key Findings

Global Yield Changes and Adaptation Effects

• Without adaptation, staple crop yields are projected to decrease by 8.3% in 2050 and 12.7% by 2098 under moderate emissions.
• Incorporating adaptive measures reduces yield losses by approximately 12%, lowering losses to 7.8% in 2050 and 11.2% in 2098.
• Adaptation is characterized as “partially protective,” indicating that while it mitigates some losses, substantial reductions in yields remain.

Regional and Crop-Specific Variations

• Yield losses vary by crop, ranging from just over 1% loss for rice to 22.4% loss for soybean by the end of the century.
• Rice yields are less affected due to compensatory effects of rising nighttime temperatures.
• Regional disparities are significant:
  • Africa faces a projected 16% yield decrease by 2098 without adaptation, reduced to 11.6% with adaptation.
  • North America shows minimal benefit from adaptation, with losses decreasing marginally from 21.0% to 20.8%.
• “Breadbasket” regions like the US and Europe, despite high yields, have lower adaptive capacity, increasing global food security risks.
• Subsistence farmers, especially those dependent on cassava, are also vulnerable, highlighting inequalities relevant to SDG 1 (No Poverty) and SDG 10 (Reduced Inequalities).

Caloric Output and Food Security Implications

• Global caloric output is projected to decline nearly linearly by 554 trillion kilocalories per 1°C of warming, equivalent to a loss of about 120 kcal per person per day per 1°C.
• A 3°C increase could equate to a global population “giving up breakfast” daily, underscoring critical challenges for SDG 2 (Zero Hunger) and SDG 3 (Good Health and Well-being).
• The study’s approach linking temperature changes to caloric output enhances policy relevance for climate adaptation strategies.

Implications for Sustainable Development Goals

• SDG 2 (Zero Hunger): The study highlights the urgent need to enhance agricultural resilience to secure food supplies amid climate change.
• SDG 13 (Climate Action): Emphasizes the importance of adaptive measures in agriculture to mitigate climate impacts.
• SDG 1 (No Poverty) and SDG 10 (Reduced Inequalities): Addressing disparities in adaptive capacity between wealthy “breadbasket” regions and poorer, subsistence farming communities is critical.
• SDG 12 (Responsible Consumption and Production): Encourages sustainable agricultural practices that balance yield optimization with resilience.
• SDG 15 (Life on Land): Supports sustainable land use and crop diversification as part of adaptation strategies.

Conclusions and Recommendations

1. Adaptation measures can significantly mitigate yield losses but are not sufficient alone to prevent substantial declines in staple crop production.
2. Policy frameworks should prioritize supporting farmers’ adaptive capacity, especially in high-yield but low-resilience regions.
3. Investment in research, technology transfer, and knowledge dissemination is essential to enhance climate-resilient agriculture, contributing to multiple SDGs.
4. Future studies should integrate empirical data with process-based models to capture a broader range of potential climate futures and adaptation pathways.

Expert Commentary

Dr. Andrew Hultgren, lead researcher, emphasizes that real-world farmer adaptation is “partially protective” and essential for reducing yield losses. Dr. Jyoti Singh from Columbia University highlights the study’s comprehensive dataset and its contribution to empirical agricultural impact modeling, while noting limitations in predicting future adaptation scenarios.

Source: Adapted from Carbon Brief, with permission. Original study: Hultgren et al. (2025), Nature.

1. Sustainable Development Goals (SDGs) Addressed or Connected

1. SDG 2: Zero Hunger
   • The article focuses on staple crop yields (cassava, maize, rice, sorghum, soya bean, wheat) and their projected decreases due to climate change, directly impacting food security and hunger.
2. SDG 13: Climate Action
   • The study examines the impact of climate change on agriculture and the role of adaptation measures to mitigate yield losses, highlighting the need for climate resilience.
3. SDG 1: No Poverty
   • The article discusses the disproportionate impacts on poorer regions and subsistence farmers, linking climate impacts on agriculture to poverty risks.
4. SDG 12: Responsible Consumption and Production
   • Adaptive measures such as switching crop varieties and adjusting irrigation relate to sustainable agricultural practices.

2. Specific Targets Under Those SDGs Identified

1. SDG 2: Zero Hunger
   • Target 2.3: By 2030, double the agricultural productivity and incomes of small-scale food producers, including through secure and equal access to land, technology, and markets.
   • Target 2.4: Ensure sustainable food production systems and implement resilient agricultural practices that increase productivity and production.
   • Target 2.1: End hunger and ensure access by all people to safe, nutritious, and sufficient food all year round.
2. SDG 13: Climate Action
   • Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters in all countries.
   • Target 13.2: Integrate climate change measures into national policies, strategies, and planning.
3. SDG 1: No Poverty
   • Target 1.5: Build the resilience of the poor and those in vulnerable situations and reduce their exposure and vulnerability to climate-related extreme events and other economic, social, and environmental shocks and disasters.
4. SDG 12: Responsible Consumption and Production
   • Target 12.2: Achieve the sustainable management and efficient use of natural resources.
   • Target 12.3: Halve per capita global food waste and reduce food losses along production and supply chains.

3. Indicators Mentioned or Implied to Measure Progress

1. Crop Yield Changes
   • Percentage change in yields of staple crops (cassava, maize, rice, sorghum, soya bean, wheat) under different warming scenarios (RCP4.5 and RCP8.5) and timeframes (2050, 2098).
   • Regional yield loss percentages, e.g., 16% decrease in Africa without adaptation, reduced to 11.6% with adaptation.
2. Adaptive Capacity
   • Reduction in yield losses due to adaptive measures (e.g., switching crop varieties, irrigation adjustments), quantified as a 12% mitigation of losses globally.
   • Comparison of yield losses between regions with different adaptive capacities (e.g., breadbasket regions vs. poorer regions).
3. Caloric Output
   • Global calorific output decrease measured in trillion kilocalories per 1°C warming (554tn kcal per 1°C), and per capita daily caloric loss (approx. 120 kcal per person per day per 1°C).
4. Socioeconomic Pathways
   • Use of SSP3 socioeconomic pathway to model income and development scenarios affecting adaptation capacity.

4. Table of SDGs, Targets, and Indicators

Source: eco-business.com