Strong isoprene emission response to temperature in tundra vegetation

Biogenic emissions of volatile organic compounds (BVOCs) are a crucial component of biosphere-atmosphere interactions. In northern latitudes, climate change is amplified by feedback processes in which BVOCs have a recognized, yet poorly quantified role, mainly due to a lack of measurements and concomitant modelling gaps. Hence, current Earth system models mostly rely on temperature responses measured on vegetation from lower latitudes, rendering their predictions highly uncertain.

We used Proton Transfer Reaction -Time of Flight- Mass Spectrometry (PTR-TOF-MS) and eddy covariance to measure ecosystem-level isoprene fluxes at two contrasting ecosystems in Sweden and Norway during an entire growing season. Measured fluxes showed that tundra isoprene emissions responded vigorously to temperature increases, with Q₁₀ temperature coefficients of up to 20.8; that is 3.5 times the Q₁₀ derived from the equivalent model results. Our results demonstrate that tundra vegetation possesses the potential to substantially boost its isoprene emissions in response to future rising temperatures, at rates that exceed the current Earth system model predictions.