Not so robust: Robusta coffee production is highly sensitive to temperature.

Area of Science:

• Agricultural Science
• Climate Change Adaptation
• Agronomy

Background:

• Coffea canephora (robusta coffee) is considered heat-tolerant and crucial for global coffee production.
• Existing estimates of robusta's optimal temperature range (22-30°C) are based on its native habitat and may not reflect actual production conditions.
• Climate change poses a significant threat to coffee production, necessitating accurate assessments of crop resilience.

Purpose of the Study:

• To quantify the optimal temperature range for robusta coffee production using real-world yield data.
• To re-evaluate the heat tolerance of robusta coffee in light of climate change projections.
• To provide accurate data for future climate change adaptation strategies in coffee farming.

Main Methods:

• Utilized 10 years of yield data from 798 robusta coffee farms in Southeast Asia.
• Integrated high-resolution precipitation and temperature data with farm-level observations.
• Employed hierarchical Bayesian modeling to analyze climate-yield relationships and quantify optimal temperature thresholds.

Main Results:

• Climate-based models effectively explained yield variation (cross-validated mean R² = 0.51).
• Identified an optimal mean annual temperature for robusta production below 20.5°C (mean min/max ≤16.2/24.1°C), significantly lower than current estimates.
• Yields decreased by 50% at mean annual temperatures above 25.1°C, and every 1°C increase above the optimal range resulted in substantial yield declines.

Conclusions:

• Robusta coffee is more sensitive to temperature increases than previously assumed.
• Current assessments likely overestimate suitable robusta production areas under climate change.
• Projected temperature increases threaten robusta coffee production, impacting the global coffee industry and farmer livelihoods.