Wheat leaves in high-CO2 environments heat up by 1.7 degrees Celsius regardless of how much they sweat.
Established climate theories assume that plants get hotter under high CO2 because they close their pores and stop sweating. Experimental data shows that the warming actually happens because of how the entire crop canopy exchanges energy with the air. Even when the plant pores stay wide open, the increased CO2 creates a physical heat trap on the leaf surface. This extra heat can damage crops and reduce yields far more than current climate models predict. We have to reconsider how we plan for food security as the atmosphere changes.
Elevated CO2 increases leaf temperature independently of stomatal regulation
research_square · rs-9493050
Abstract Leaf temperature regulates plant physiology, affecting photosynthesis, water use and heat stress. Under elevated [CO2], increases in leaf temperature are commonly attributed to reduced stomatal conductance, yet direct field evidence remains scarce. Using a multi-season free-air CO2 enrichment experiment, we show that a +150 μmol mol⁻1 increase in [CO2] increases the leaf–air temperature difference (ΔT) by ~1.2–1.7 °C in wheat, independently of stomatal regulation. Parallel ΔT–stomatal c