Preprints
https://doi.org/10.5194/esd-2020-41
https://doi.org/10.5194/esd-2020-41

  15 Jul 2020

15 Jul 2020

Review status: a revised version of this preprint was accepted for the journal ESD and is expected to appear here in due course.

Resolving ecological feedbacks on the ocean carbon sink in Earth system models

David I. Armstrong McKay1,2, Sarah E. Cornell1,2, Katherine Richardson3, and Johan Rockström1,4 David I. Armstrong McKay et al.
  • 1Stockholm Resilience Centre, Stockholm University, Stockholm, 10691, Sweden
  • 2BolinCentre for Climate Research, Stockholm University, Stockholm, 10691, Sweden
  • 3Globe Institute, Center for Macroecology, Evolution and Climate, University of Copenhagen, Copenhagen, 2100, Denmark
  • 4Potsdam Institute for Climate Impact Research, Potsdam,14473, Germany

Abstract. The Earth’s oceans are one of the largest sinks in the Earth system for anthropogenic CO2 emissions, acting as a negative feedback on climate change. Earth system models predict, though, that climate change will lead to a weakening ocean carbon uptake rate as warm water holds less dissolved CO2 and biological productivity declines. However, most Earth system models do not incorporate the impact of warming on bacterial remineralisation and rely on simplified representations of plankton ecology that do not resolve the potential impact of climate change on ecosystem structure or elemental stoichiometry. Here we use a recently-developed extension of the cGEnIE Earth system model (ecoGEnIE) featuring a trait-based scheme for plankton ecology (ECOGEM), and also incorporate cGEnIE's temperature-dependent remineralisation (TDR) scheme. This enables evaluation of the impact of both ecological dynamics and temperature-dependent remineralisation on the soft-tissue biological pump in response to climate change. We find that including TDR strengthens the biological pump relative to default runs due to increased nutrient recycling, while ECOGEM weakens the biological pump by enabling a shift to smaller plankton classes. However, interactions with concurrent ocean acidification cause opposite sign responses for the carbon sink in both cases: TDR leads to a smaller sink relative to default runs whereas ECOGEM leads to a larger sink. Combining TDR and ECOGEM results in a net strengthening of the biological pump and a small net reduction in carbon sink relative to default. These results clearly illustrate the substantial degree to which ecological dynamics and biodiversity modulate the strength of climate-biosphere feedbacks, and demonstrate that Earth system models need to incorporate more ecological complexity in order to resolve carbon sink weakening.

David I. Armstrong McKay et al.

 
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
 
Status: closed
Status: closed
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement

David I. Armstrong McKay et al.

David I. Armstrong McKay et al.

Viewed

Total article views: 501 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
334 146 21 501 18 25 28
  • HTML: 334
  • PDF: 146
  • XML: 21
  • Total: 501
  • Supplement: 18
  • BibTeX: 25
  • EndNote: 28
Views and downloads (calculated since 15 Jul 2020)
Cumulative views and downloads (calculated since 15 Jul 2020)

Viewed (geographical distribution)

Total article views: 491 (including HTML, PDF, and XML) Thereof 491 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 18 Jun 2021
Download
Short summary
We use an Earth system model with two new ecosystem features (plankton size traits and temperature-sensitive nutrient recycling) to revaluate the effect of climate change on organic carbon removal (the biological pump) and ocean carbon drawdown. These features lead to contrary pump responses to warming, and a stronger pump counter-intuitively leads to less carbon drawdown overall. These results show the importance of including ecological dynamics in models for understanding climate feedbacks.
Altmetrics