Climate Change Impact on Global Crop Yields

Recent studies show alarming declines in global crop yields due to rising temperatures. Each additional degree Celsius of surface warming may reduce daily calorie availability by 120 calories per person. Northern India’s wheat production faces some of the sharpest losses worldwide. Despite farmers’ efforts to adapt, only about one-third of losses from climate change can be offset by 2100 if emissions continue unchecked. This threatens global food security, especially in key agricultural regions.

Projected Crop Yield Declines

A comprehensive analysis covering six staple crops—rice, wheat, maize, soybean, sorghum, and cassava—shows severe yield declines by century’s end. Yield losses could average 41% in wealthy regions and 28% in low-income areas under high emissions. Wheat is most vulnerable with losses up to 100% in parts of northern and central India. Rice may see mixed effects due to its tolerance to warmer minimum temperatures. Maize, soybean, sorghum, and cassava also face reductions.

Regional and Economic Disparities

Losses vary by region and income level. Wealthier breadbasket regions suffer more due to their reliance on modern agriculture. Poorer areas relying on cassava also face major risks. Middle-temperature zones experience the greatest yield drops, while already hot regions show smaller impacts since crops there are somewhat heat-adapted. This uneven impact may worsen global food inequality, affecting both rich and poor populations differently.

Limits of Adaptation

Farmers’ adaptive measures, such as changing crop varieties or practices, reduce yield losses but cannot fully compensate. Adaptation lowers calorie deficits by roughly 34% by 2100 under high emissions. Rice benefits most from adaptation, while wheat gains least. Economic development sometimes increases risk-taking in wheat farming, worsening losses. Adaptation benefits are uneven across crops and regions, denoting the need for targeted strategies.

Impact on Global Food Systems

The six crops studied provide two-thirds of global calorie supply. Declines in yields threaten food availability worldwide. Regions that currently produce abundant crops face the steepest losses, which may disrupt global food trade and prices. Subsistence farmers risk food insecurity due to cassava yield drops. These findings tell the urgency of reducing emissions and enhancing adaptive capacity to safeguard future food security.

Scientific Methodology

The study used climate and socioeconomic data from 24,378 regions in 54 countries. Projections were made under high and moderate emissions scenarios until 2100. The research combined crop modelling with adaptation scenarios to estimate yield changes. Probabilities of yield decline varied by crop, with wheat showing a 90% chance of reduction under high emissions. This robust approach provides detailed vital information about future agricultural risks.

Questions for UPSC:

1. Point out the impacts of climate change on global food security and the role of adaptation in mitigating these effects.
2. Critically analyse the regional disparities in agricultural productivity due to climate change with suitable examples from India and other countries.
3. Estimate the challenges faced by subsistence farmers in the tropics due to climate-induced crop yield changes and suggest policy measures to address them.
4. Underline the relationship between economic development and climate risk-taking in agriculture and how it influences crop yield outcomes globally.

Answer Hints:

1. Point out the impacts of climate change on global food security and the role of adaptation in mitigating these effects.

1. Global surface temperature rise reduces daily calorie availability by about 120 calories per person per °C increase.
2. Major staple crops like wheat, maize, soybean, sorghum, cassava face yield declines by 2100, threatening food supply.
3. Wheat is most vulnerable, with losses up to 100% in northern and central India under high emissions.
4. Adaptation (changing practices, crop varieties) offsets only about one-third of climate-related yield losses by century-end.
5. Rice shows some resilience due to tolerance to higher minimum temperatures; adaptation benefits vary by crop.
6. Without emission reductions and enhanced adaptation, global food security risks severe disruption and increased hunger.

2. Critically analyse the regional disparities in agricultural productivity due to climate change with suitable examples from India and other countries.

1. Northern India’s wheat-growing regions face some of the most severe projected yield losses globally (40-100%).
2. China, Russia, US, Canada show moderate wheat yield declines (30-40%), while Eastern and Western Europe, Africa, South America face smaller losses (15-25%).
3. Wealthier regions suffer higher average losses (~41%) due to concentration of modern agriculture and breadbaskets.
4. Low-income tropical regions reliant on cassava face risks but somewhat less yield decline (~28%) due to heat adaptation.
5. Middle-temperature zones experience greatest yield losses; already hot regions show smaller impacts as crops are heat-adapted.
6. Disparities exacerbate global food inequality, affecting both rich and poor regions differently.

3. Estimate the challenges faced by subsistence farmers in the tropics due to climate-induced crop yield changes and suggest policy measures to address them.

1. Subsistence farmers rely heavily on cassava, which faces yield declines under warming scenarios.
2. Limited resources and technology restrict their ability to adapt effectively to climate stress.
3. Higher vulnerability due to dependence on small-scale, rainfed agriculture and exposure to extreme weather.
4. Policy measures – promote climate-resilient crop varieties and diversified cropping systems.
5. Enhance access to extension services, credit, insurance, and climate information for smallholders.
6. Invest in infrastructure and social safety nets to reduce food insecurity and livelihood risks.

4. Underline the relationship between economic development and climate risk-taking in agriculture and how it influences crop yield outcomes globally.

1. Higher GDP per capita correlates with increased risk-taking in wheat farming under climate stress.
2. Farmers in developed regions may intensify production or use marginal lands, exacerbating yield losses despite adaptation.
3. Economic development enables some adaptive capacity but can lead to greater exposure to weather variability.
4. Wheat losses are amplified in wealthier regions due to riskier farming choices linked to rising incomes.
5. Adaptation benefits are uneven; development alone does not guarantee reduced climate vulnerability.
6. Balanced risk management and sustainable farming practices are crucial to mitigate negative impacts globally.