The temperature sensitivity of mono- and sesquiterpene emissions from terrestrial vegetation: Insights from a meta-analysis

The emission of mono- and sesquiterpenes from terrestrial vegetation plays a significant role in ecological interactions and atmospheric chemistry. Previous research has suggested that global emissions of these hydrocarbons are largely driven by responses to abiotic stress and can be simulated using a fixed exponential relationship (β coefficient) between different forest ecosystems and environmental conditions. However, our meta-analysis of published emission data (89 studies/835 β coefficients) reveals that the relationship between mono- and sesquiterpene emissions and temperature is more complex than previously thought. We have found that co-occurring environmental stresses can amplify the temperature sensitivity of monoterpene emissions, which is primarily related to the specific plant functional type (PFT). In contrast, the temperature sensitivity of sesquiterpene emissions decreases over the years. On average, warmer ecosystems appear more sensitive, indicating that plants adjust their emission rates in response to thermal stress. When a PFT-dependent β coefficient for monoterpenes was implemented in a biogenic emission model and coupled with a chemistry-climate model, it was found that atmospheric processes are highly sensitive to this coefficient and subject to amplified variations under rising temperatures.