Carbon Cycle Response to Temperature Overshoot Beyond 2°C: An Analysis of CMIP6 Models
Abstract There is a substantial gap between the current emissions of greenhouse gases and levels required for achieving the 2°C and 1.5°C temperature targets of the Paris Agreement. Understanding the implications of a temperature overshoot is thus an increasingly relevant research topic. Here we exp...
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doaj-8fe9ed0d8a874230b8949a6e393c7a022021-05-27T20:40:30ZengAmerican Geophysical Union (AGU)Earth's Future2328-42772021-05-0195n/an/a10.1029/2020EF001967Carbon Cycle Response to Temperature Overshoot Beyond 2°C: An Analysis of CMIP6 ModelsI. Melnikova0O. Boucher1P. Cadule2P. Ciais3T. Gasser4Y. Quilcaille5H. Shiogama6K. Tachiiri7T. Yokohata8K. Tanaka9Institut Pierre‐Simon Laplace Sorbonne Université / CNRS Paris FranceInstitut Pierre‐Simon Laplace Sorbonne Université / CNRS Paris FranceInstitut Pierre‐Simon Laplace Sorbonne Université / CNRS Paris FranceLaboratoire des Sciences du Climat et de l’Environnement (LSCE) Commissariat à l’énergie atomique et aux énergies alternatives (CEA CNRS UVSQ) Gif‐sur‐Yvette FranceInternational Institute for Applied Systems Analysis (IIASA) Laxenberg AustriaInternational Institute for Applied Systems Analysis (IIASA) Laxenberg AustriaCenter for Global Environmental Research (CGER) National Institute for Environmental Studies (NIES) Tsukuba JapanCenter for Global Environmental Research (CGER) National Institute for Environmental Studies (NIES) Tsukuba JapanCenter for Global Environmental Research (CGER) National Institute for Environmental Studies (NIES) Tsukuba JapanCenter for Global Environmental Research (CGER) National Institute for Environmental Studies (NIES) Tsukuba JapanAbstract There is a substantial gap between the current emissions of greenhouse gases and levels required for achieving the 2°C and 1.5°C temperature targets of the Paris Agreement. Understanding the implications of a temperature overshoot is thus an increasingly relevant research topic. Here we explore the carbon cycle feedbacks over land and ocean in the SSP5‐3.4‐OS overshoot scenario by using an ensemble of Coupled Model Intercomparison Project 6 Earth system models. Models show that after the CO2 concentration and air temperature peaks, land and ocean are decreasing carbon sinks from the 2,040s and become sources for a limited time in the 22nd century. The decrease in the carbon uptake precedes the CO2 concentration peak. The early peak of ocean uptake stems from its dependency on the atmospheric CO2 growth rate. The early peak of the land uptake occurs due to a larger increase in ecosystem respiration than the increase in gross primary production, as well as due to a concomitant increase in land‐use change emissions primarily attributed to the wide implementation of biofuel croplands. The carbon cycle feedback parameters amplify after the CO2 concentration and temperature peaks due to inertia of the Earth system so that land and ocean absorb more carbon per unit change in the atmospheric CO2 change (stronger negative feedback) and lose more carbon per unit temperature change (stronger positive feedback) compared to if the feedbacks stayed unchanged. The increased negative CO2 feedback outperforms the increased positive climate feedback. This feature should be investigated under other scenarios.https://doi.org/10.1029/2020EF001967Carbon cyclecarbon‐climate feedbackcarbon‐concentration feedbackCMIP6SSP5‐3.4‐OSovershoot |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
I. Melnikova O. Boucher P. Cadule P. Ciais T. Gasser Y. Quilcaille H. Shiogama K. Tachiiri T. Yokohata K. Tanaka |
spellingShingle |
I. Melnikova O. Boucher P. Cadule P. Ciais T. Gasser Y. Quilcaille H. Shiogama K. Tachiiri T. Yokohata K. Tanaka Carbon Cycle Response to Temperature Overshoot Beyond 2°C: An Analysis of CMIP6 Models Earth's Future Carbon cycle carbon‐climate feedback carbon‐concentration feedback CMIP6 SSP5‐3.4‐OS overshoot |
author_facet |
I. Melnikova O. Boucher P. Cadule P. Ciais T. Gasser Y. Quilcaille H. Shiogama K. Tachiiri T. Yokohata K. Tanaka |
author_sort |
I. Melnikova |
title |
Carbon Cycle Response to Temperature Overshoot Beyond 2°C: An Analysis of CMIP6 Models |
title_short |
Carbon Cycle Response to Temperature Overshoot Beyond 2°C: An Analysis of CMIP6 Models |
title_full |
Carbon Cycle Response to Temperature Overshoot Beyond 2°C: An Analysis of CMIP6 Models |
title_fullStr |
Carbon Cycle Response to Temperature Overshoot Beyond 2°C: An Analysis of CMIP6 Models |
title_full_unstemmed |
Carbon Cycle Response to Temperature Overshoot Beyond 2°C: An Analysis of CMIP6 Models |
title_sort |
carbon cycle response to temperature overshoot beyond 2°c: an analysis of cmip6 models |
publisher |
American Geophysical Union (AGU) |
series |
Earth's Future |
issn |
2328-4277 |
publishDate |
2021-05-01 |
description |
Abstract There is a substantial gap between the current emissions of greenhouse gases and levels required for achieving the 2°C and 1.5°C temperature targets of the Paris Agreement. Understanding the implications of a temperature overshoot is thus an increasingly relevant research topic. Here we explore the carbon cycle feedbacks over land and ocean in the SSP5‐3.4‐OS overshoot scenario by using an ensemble of Coupled Model Intercomparison Project 6 Earth system models. Models show that after the CO2 concentration and air temperature peaks, land and ocean are decreasing carbon sinks from the 2,040s and become sources for a limited time in the 22nd century. The decrease in the carbon uptake precedes the CO2 concentration peak. The early peak of ocean uptake stems from its dependency on the atmospheric CO2 growth rate. The early peak of the land uptake occurs due to a larger increase in ecosystem respiration than the increase in gross primary production, as well as due to a concomitant increase in land‐use change emissions primarily attributed to the wide implementation of biofuel croplands. The carbon cycle feedback parameters amplify after the CO2 concentration and temperature peaks due to inertia of the Earth system so that land and ocean absorb more carbon per unit change in the atmospheric CO2 change (stronger negative feedback) and lose more carbon per unit temperature change (stronger positive feedback) compared to if the feedbacks stayed unchanged. The increased negative CO2 feedback outperforms the increased positive climate feedback. This feature should be investigated under other scenarios. |
topic |
Carbon cycle carbon‐climate feedback carbon‐concentration feedback CMIP6 SSP5‐3.4‐OS overshoot |
url |
https://doi.org/10.1029/2020EF001967 |
work_keys_str_mv |
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