Future vegetation shifts trigger strong local BVOC impacts on atmospheric secondary organic aerosol in high latitudes
Jing Tang, Researcher at INES, will give a seminar. The title and abstract will be posted shortly.
The amplified warming in high latitudes will likely cause continual large changes in vegetation composition and plant productivity, which could profoundly alter plant emissions of Biogenic Volatile Organic Compounds (BVOCs). The impacts of the short-lived BVOCs on the climate system in high latitudes are largely uncertain due to the scarcity of emission data and underrepresented plant variations.
We explored historical and future changes in the emissions of dominant BVOCs, isoprene and monoterpenes, from boreal and tundra regions using a dynamic vegetation model, LPJ-GUESS. The model has integrated the latest BVOC observations and has detailed representations of tundra vegetation, permafrost and wetlands. For the future (i.e., 2015-2100), we selected 15 CMIP6 climate predictions to drive LPJ-GUESS, and ran different factorial experiments to assess the relative importance of climatic drivers, vegetation changes, atmospheric CO2, and nitrogen availability in determining future BVOC emissions. The modelled BVOCs from LPJ-GUESS were fed into global chemistry transport model version 5 (TM5) to assess future BVOC impacts on the atmospheric Secondary Organic Aerosol (SOA) at the regional scale.
The results showed an increase in total isoprene emission, but a moderate increase or a decrease of total monoterpene emissions under different future scenarios. For the regions where boreal needle-leaved evergreen trees (monoterpene-emitters) are overtaken by broad-leaved deciduous trees (isoprene-emitters), we see strong decreasing trends for monoterpenes. The predicted northward movement of boreal needle-leaved trees is associated with strong increasing trends of monoterpenes in northern Canada and Russia. The factorial experiments revealed that under low CO2 emission scenarios, the positive trends in isoprene emission were largely driven by vegetation changes, while under a high CO2 emission scenario, the trends were determined by plant CO2 fertilization, vegetation changes and CO2 inhibition of isoprene synthesis. The TM5 results showed that the future changes in BVOC emissions from the high latitudes strongly increased surface SOA concentrations in most part of tundra and boreal regions and resulted in up to 40% and 6% increases in SOA and aerosol optical depth at 550 nm, respectively. Spatially, the feedbacks on SOA were largely linked to the altered monoterpene emissions which is caused by the shifted vegetation under changing climate.
How to join
This seminar will be given online using Zoom. Use the following link and information to connect to the meeting:
Meeting ID: 682 3216 9029