Skip to content

The CO2 inhibition of terrestrial isoprene emission significantly affects future ozone projections

by P J Young, A Arneth, G Schurgers, G Zeng, J A Pyle
Atmos. Chem. Phys. Atmospheric Chemistry and Physics ()
Get full text at journal

Abstract

Simulations of future tropospheric composition often include substantial increases in biogenic isoprene emis-sions arising from the Arrhenius-like leaf emission response and warmer surface temperatures, and from enhanced veg-etation productivity in response to temperature and atmo-spheric CO 2 concentration. However, a number of recent laboratory and field data have suggested a direct inhibition of leaf isoprene production by increasing atmospheric CO 2 con-centration, notwithstanding isoprene being produced from precursor molecules that include some of the primary prod-ucts of carbon assimilation. The cellular mechanism that un-derlies the decoupling of leaf photosynthesis and isoprene production still awaits a full explanation but accounting for this observation in a dynamic vegetation model that contains a semi-mechanistic treatment of isoprene emissions has been shown to change future global isoprene emission estimates notably. Here we use these estimates in conjunction with a chemistry-climate model to compare the effects of isoprene simulations without and with a direct CO 2 -inhibition on late 21st century O 3 and OH levels. The impact on surface O 3 was significant. Including the CO 2 -inhibition of isoprene re-sulted in opposing responses in polluted (O 3 decreases of up to 10 ppbv) vs. less polluted (O 3 increases of up to 10 ppbv) source regions, due to isoprene nitrate and peroxy acetyl ni-trate (PAN) chemistry. OH concentration increased with rel-atively lower future isoprene emissions, decreasing methane lifetime by ∼7 months (6.6%). Our simulations underline the Correspondence to: P. J. Young (paul.j.young@noaa.gov) large uncertainties in future chemistry and climate studies due to biogenic emission patterns and emphasize the prob-lems of using globally averaged climate metrics (such as global radiative forcing) to quantify the atmospheric impact of reactive, heterogeneously distributed substances.

Cite this document (BETA)

Authors on Mendeley

Readership Statistics

52 Readers on Mendeley
by Discipline
 
42% Environmental Science
 
35% Earth and Planetary Sciences
 
12% Agricultural and Biological Sciences
by Academic Status
 
38% Researcher
 
25% Student > Ph. D. Student
 
10% Professor > Associate Professor
by Country
 
6% United Kingdom
 
4% United States
 
2% Australia

Sign up today - FREE

Mendeley saves you time finding and organizing research. Learn more

  • All your research in one place
  • Add and import papers easily
  • Access it anywhere, anytime

Start using Mendeley in seconds!

Sign up & Download

Already have an account? Sign in