High temperature sensitivity of monoterpene emissions from global vegetation

Abstract

Terrestrial vegetation emits vast amounts of monoterpenes into the atmosphere, influencing ecological interactions and atmospheric chemistry. Global emissions, mostly driven by responses to abiotic stress, are simulated as a function of temperature with a fixed exponential relationship (β coefficient) across forest ecosystems and environmental conditions. We applied meta-analysis algorithms on all published monoterpene emission data and show that this relationship is more intricate and sensitive than previously thought. We find that co-occurring environmental stresses amplify the temperature sensitivity of the emissions that is primarily related to the specific plant functional type (PFT). On average, warmer ecosystems appear more sensitive, indicating the adjustment of plants in response to thermal stress. Implementing a PFT-dependent β in a biogenic emission model, coupled with a chemistry – climate model, demonstrated that atmospheric processes are exceptionally dependent on monoterpene emissions which are subject to amplified variations under rising temperatures.