Water-Smart Agriculture Boosts Cereal Resilience in South Asia

Challenge

South Asia’s dense population faces food insecurity as climate change disrupts water availability and threatens cereal yields.

Solution

This project produced local-scale climate scenarios and applied crop water models to simulate yield responses and devise water-efficient adaptation strategies.

Overview

South Asia, home to over a fifth of the world’s population and the highest regional Global Hunger Index, relies heavily on cereal crops like wheat, rice, and maize for food security and livelihoods. The region faces mounting threats to water, energy, and food security under climate change. IPCC projections show that rising temperatures and shifting rainfall patterns will reduce agricultural productivity in this already vulnerable region. To address this, the Asia‑Pacific Network for Global Change Research funded a 2‑year project led by the Global Change Impact Studies Centre in Pakistan.

Achievements

Local-scale climate scenarios were created for South Asia. This achievement involved a process called statistical downscaling – taking broad regional climate predictions and making them much more specific and useful for smaller areas. The researchers achieved this by analyzing data from CORDEX regional climate model (RCM) ensembles (a collection of detailed computer simulations that predict climate for specific regions) and applying the quantile mapping approach (a method to fine-tune climate data to better match local conditions). The project also successfully adapted and tested crop water models (the FAO’s AquaCrop [a crop water productivity simulation model] and APSIM [Agricultural Production Systems sIMulator]) – these are computer programs that simulate how crops grow and use water under different conditions – to help predict yields and develop farming strategies that use water more efficiently in South Asia.

Approach

1. Compiled observed station data (PMD – Pakistan Meteorological Department) and reanalysis for 1981–2005 validation.
2. Obtained CORDEX RCM ensembles and validated temperature and precipitation biases.
3. Generated point-scale future scenarios via statistical downscaling to correct bias.
4. Ran AquaCrop and APSIM to assess yield and water productivity of wheat, rice, and maize across five countries and multiple agro-ecological zones.
5. Mapped changes in growing degree days (a measure of accumulated heat influencing plant growth), consecutive heat days, and their effects on crop phenology (the timing of key growth stages).
6. Devised climate-smart adaptation strategies – optimized irrigation scheduling, deficit irrigation, zero-tillage integration, and selection of heat-tolerant cultivars – for policy uptake.

Findings & implications

• The model bias (the difference between modelled and observed temperatures) for Rabi‑season Tmax and Tmin (maximum and minimum daily temperatures) had been under ±1°C in major wheat zones, and growing‑degree‑day projections rose by up to 1,000 units under RCP 8.5 by mid‑century in southeastern Pakistan, jeopardizing wheat suitability.
• Tmin had been projected to increase by 2.1°C (RCP 4.5) to 5.4°C (RCP 8.5), and Tmax by 2.0–5.4°C, which were expected to compress crop lifecycles and reduce yields by up to 40% without adaptation.
• Simulation of rice in Bangladesh and Sri Lanka likewise showed declines in attainable yields of 17–42% under future scenarios.
• Adoption of climate‑smart water management and cropping practices was found to mitigate up to half of these losses.

This project linked robust local climate projections with crop‑water modelling to equip policymakers and extension services with actionable strategies to safeguard staple cereal production and build resilience in South Asia’s agrarian communities.

Project details

Acknowledgements

This case study was made possible thanks to the Asia-Pacific Network for Global Change Research (APN), which funded the original project. The project was led by Nuzba Shaheen from the Global Change Impact Studies Centre (GCISC), Pakistan. Key organizations collaborating on this research included: GCISC (Pakistan), Natural Resources Management Centre, Department of Agriculture (Sri Lanka), Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Bangladesh, Zaman University (Cambodia), and Newcastle University (United Kingdom). Additional contributions were made by the Climate Change, Alternate Energy and Water Resources Institute (CAEWRI), Pakistan, particularly for gathering data, building computer models, and training others.

Related information

• Project Permalink
• Shaheen, N., Punyawardena, B. V. R., Abdullah, H. M., Fowler, H., Kum, V., & Akbar, G. (2020). Project Final Report: CAF2016‑RR07‑CMY‑Shaheen. Asia‑Pacific Network for Global Change Research. https://www.apn-gcr.org/publication/project-final-report-caf2016-rr07-cmy-shaheen/
• Shaheen, N., Jahandad, A., Goheer, M. A., & Ahmad, Q. A. (2020). Future changes in growing degree days of wheat crop in Pakistan as simulated in CORDEX South Asia experiments. APN Science Bulletin, 10(1), 82‑89. https://doi.org/10.30852/sb.2020.1221
• APN Facebook
• APN LinkedIn
• APN X