Preprints
https://doi.org/10.5194/bg-2021-191
https://doi.org/10.5194/bg-2021-191

  26 Jul 2021

26 Jul 2021

Review status: this preprint is currently under review for the journal BG.

The effects of varying drought-heat signatures on terrestrial carbon dynamics and vegetation composition

Elisabeth Tschumi1,2, Sebastian Lienert1,2, Karin van der Wiel3, Fortunat Joos1,2, and Jakob Zscheischler1,2,4 Elisabeth Tschumi et al.
  • 1Climate and Environmental Physics, University of Bern, Bern Switzerland
  • 2Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
  • 3Royal Netherlands Meteorological Institute, De Bilt, The Netherlands
  • 4Department of Computational Hydrosystems, Helmholtz Centre for Environmental Research – UFZ, Leipzig, Germany

Abstract. The frequency and severity of droughts and heat waves are projected to increase under global warming. However, the differential impacts of climate extremes on the terrestrial biosphere and anthropogenic CO2 sink remain poorly understood. In this study, we analyse the effects of six hypothetical climate scenarios with differing drought-heat signatures, sampled from a long stationary climate model simulation, on vegetation distribution and land carbon dynamics, as modelled by a dynamic global vegetation model (LPX-Bern v1.4). The six forcing scenarios consist of a Control scenario representing a natural climate, a Noextremes scenario featuring few droughts and heatwaves, a Nocompound scenario which allows univariate hot or dry extremes but no co-occurring extremes, a Hot scenario with frequent heatwaves, a Dry scenario with frequent droughts, and a Hotdry scenario featuring frequent concurrent hot and dry extremes. We find that a climate with no extreme events increases tree coverage by up to 10 % compared to the Control and also increases ecosystem productivity as well as the terrestrial carbon pools. A climate with many heatwaves leads to an overall increase in tree coverage primarily in higher latitudes, while the ecosystem productivity remains similar to the Control. In the Dry and even more so in the Hotdry scenario, tree cover and ecosystem productivity are reduced by up to −4 % compared to the Control. Depending on the vegetation type, the effects from the Hotdry scenario are stronger than the effects from the Hot and Dry scenario combined, illustrating the importance of correctly simulating compound extremes for future impact assessment. Overall, our study illustrates how factorial model experiments can be employed to disentangle the effects from single and compound extremes.

Elisabeth Tschumi et al.

Status: open (until 13 Oct 2021)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on bg-2021-191', Martin De Kauwe, 27 Aug 2021 reply

Elisabeth Tschumi et al.

Elisabeth Tschumi et al.

Viewed

Total article views: 465 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
347 111 7 465 3 7
  • HTML: 347
  • PDF: 111
  • XML: 7
  • Total: 465
  • BibTeX: 3
  • EndNote: 7
Views and downloads (calculated since 26 Jul 2021)
Cumulative views and downloads (calculated since 26 Jul 2021)

Viewed (geographical distribution)

Total article views: 433 (including HTML, PDF, and XML) Thereof 433 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 23 Sep 2021
Download
Short summary
Droughts and heatwaves are expected to occur more often in the future but their effects on land vegetation and the carbon cycle are poorly understood. We use six climate scenarios with differing extremes occurrence and a vegetation model to analyze these effects. We find that tree coverage and associated plant productivity increases under a climate with no extremes. Frequent co-occurring droughts and heatwaves decrease plant productivity more than the combined effects of single drought or heat.
Altmetrics