India’s rice yields could fall 6.6% for every 1°C rise in global temperature
A study published in the journal Science Advances estimates that India's rice yields could fall by 6.6% for every 1°C rise in global mean temperature, more than three times higher than earlier model-based projections of around 2.1%.
The estimate is based on data from 214 field-warming experiment sites across rice-growing regions, cross-checked against seven established crop simulation models.
Crop models were found to significantly underestimate real-world heat damage: they projected a 3.8% yield loss under warming scenarios, against an observed loss of 8.1% at actual field sites.
Exposure to temperatures above 30°C during rice's reproductive stage (flowering and grain-filling) caused measurable yield losses at over 70% of the observed sites.
South and Southeast Asian rice-growing nations, including Thailand, Myanmar and the Philippines, are projected to face even steeper losses of around 7.7% yield decline per 1°C of warming.
Heat Stress During Rice's Reproductive Stage
Rice is most vulnerable to heat during its reproductive phase (panicle initiation, flowering/anthesis, and grain-filling), not during vegetative growth. Temperatures above roughly 35°C at flowering can cause spikelet sterility by impairing pollen viability, while sustained exposure above 30°C during grain-filling shortens the grain-filling duration and lowers grain weight. Crop simulation models historically under-parameterize this narrow, stage-specific heat sensitivity, which is why field observations show nearly double the yield loss that models predict.
Key Details
- Rice's most heat-sensitive window is anthesis (flowering), lasting only a few hours to a few days per plant
- India's kharif rice season (June–October) overlaps with the hottest pre-monsoon and monsoon-onset weeks, increasing exposure risk
- Comparable heat-sensitivity research has driven ICAR's development of heat-tolerant rice varieties for eastern and central India
The study's core finding — that field data shows nearly double the yield loss models project — is directly attributed to how poorly models capture this reproductive-stage heat damage mechanism.
NICRA — National Innovations in Climate Resilient Agriculture
NICRA is a flagship ICAR (Indian Council of Agricultural Research) network project launched in February 2011 to enhance the resilience of Indian agriculture to climate change and climate variability through strategic research, technology demonstration, and capacity building. It covers crops, livestock, and fisheries, with a specific focus on developing climate-resilient crop varieties (including heat- and drought-tolerant rice) and location-specific contingency plans for climatically vulnerable districts.
Key Details
- Launched February 2011 by ICAR under the Ministry of Agriculture and Farmers Welfare
- Four components: Strategic Research, Technology Demonstration, Capacity Building, and Sponsored/Competitive Grants
- Coordinated by ICAR-Central Research Institute for Dryland Agriculture (CRIDA), Hyderabad
- Has supported breeding of heat- and submergence-tolerant rice varieties for climate-stressed districts
Findings like the one in this study — that yield losses under warming are far higher than previously modelled — strengthen the case for scaling up NICRA-style climate-resilient variety development and contingency planning specifically for rice.
India's Rice Production and Food Security Stakes
Rice is a staple for roughly two-thirds of India's population and India is both the world's largest producer (around 150 million tonnes in 2024-25, over 28% of global output) and the world's largest exporter of rice (accounting for close to 40% of global rice trade). This dual role means that a domestic yield shock from climate warming has implications not only for India's own food security and inflation (rice is part of the CPI food basket) but also for global rice-importing countries that depend on Indian exports.
Key Details
- India produced a record ~150 million tonnes of rice in 2024-25, surpassing China as the top producer
- India's rice exports were around 21–22 million tonnes in 2025 after export restrictions on non-basmati varieties (imposed in 2023) were eased in early 2025
- Rice cultivation and procurement are supported by the Minimum Support Price (MSP) mechanism, recommended by the Commission for Agricultural Costs and Prices (CACP) and approved by the Cabinet Committee on Economic Affairs
A 6.6% yield loss per 1°C of warming, if realised, would strain India's dual role as top domestic staple producer and top global exporter, with knock-on effects for both domestic food price stability and global rice supply, particularly for import-dependent countries in Africa and Asia.
- Projected yield loss: 6.6% per 1°C rise in global temperature (India-specific), versus ~2.1% in earlier estimates
- Study based on 214 field-warming experiment sites, cross-checked against 7 crop models
- Crop models underestimated losses: predicted 3.8% vs observed 8.1% yield loss
- Yield losses recorded at over 70% of sites where temperatures exceeded 30°C during reproductive stages
- Southeast Asian countries (Thailand, Myanmar, Philippines) projected at ~7.7% yield loss per 1°C
- India is the world's largest rice producer (~150 million tonnes, 2024-25) and largest exporter (~40% of global trade)
- Published in the peer-reviewed journal Science Advances