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| Titel |
Influence of future climate and cropland expansion on isoprene emissions and tropospheric ozone |
| VerfasserIn |
O. J. Squire, A. T. Archibald, N. L. Abraham, D. J. Beerling, C. N. Hewitt, J. Lathière, R. C. Pike, P. J. Telford, J. A. Pyle |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 2 ; Nr. 14, no. 2 (2014-01-28), S.1011-1024 |
| Datensatznummer |
250118318
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| Publikation (Nr.) |
 copernicus.org/acp-14-1011-2014.pdf |
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| Zusammenfassung |
| Over the 21st century, changes in CO2 levels, climate and
land use are expected to alter the global distribution of
vegetation, leading to changes in trace gas emissions from plants,
including, importantly, the emissions of isoprene. This, combined
with changes in anthropogenic emissions, has the potential to impact
tropospheric ozone levels, which above a certain level are harmful
to animals and vegetation. In this study we use a biogenic emissions
model following the empirical parameterisation of the MEGAN model,
with vegetation distributions calculated by the Sheffield Dynamic
Global Vegetation Model (SDGVM) to explore a range of potential future (2095)
changes in isoprene emissions caused by changes in climate (including
natural land use changes), land use, and the inhibition of isoprene
emissions by CO2. From the present-day (2000) value of
467 Tg C yr−1, we find that the combined impact of these
factors could cause a net decrease in isoprene emissions of 259 Tg C yr−1
(55%) with individual contributions of +78 Tg C yr−1 (climate change),
−190 Tg C yr−1 (land use) and
−147 Tg C yr−1 (CO2 inhibition). Using these
isoprene emissions and changes in anthropogenic emissions, a series
of integrations is conducted with the UM-UKCA chemistry-climate
model with the aim of examining changes in ozone over the 21st
century. Globally, all combined future changes cause a decrease in
the tropospheric ozone burden of 27 Tg (7%) from
379 Tg in the present-day. At the surface, decreases in
ozone of 6–10 ppb are calculated over the oceans and
developed northern hemispheric regions, due to reduced NOx
transport by PAN and reductions in NOx emissions in these
areas respectively. Increases of 4–6 ppb are calculated in
the continental tropics due to cropland expansion in these regions,
increased CO2 inhibition of isoprene emissions, and higher
temperatures due to climate change. These effects outweigh the
decreases in tropical ozone caused by increased tropical isoprene
emissions with climate change. Our land use change scenario
consists of cropland expansion, which is most pronounced in the
tropics. The tropics are also where land use change causes the
greatest increases in ozone. As such there is potential for
increased crop exposure to harmful levels of ozone. However, we find
that these ozone increases are still not large enough to raise ozone
to such damaging levels. |
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