Carbon Cycle Response to Temperature Overshoot Beyond 2°C: An Analysis of CMIP6 Models

Bibliographic Details
Title: Carbon Cycle Response to Temperature Overshoot Beyond 2°C: An Analysis of CMIP6 Models
Authors: I. Melnikova, O. Boucher, P. Cadule, P. Ciais, T. Gasser, Y. Quilcaille, H. Shiogama, K. Tachiiri, T. Yokohata, K. Tanaka
Source: Earth's Future, Vol 9, Iss 5, Pp n/a-n/a (2021)
Publisher Information: Wiley, 2021.
Publication Year: 2021
Collection: LCC:Environmental sciences
LCC:Ecology
Subject Terms: Carbon cycle, carbon‐climate feedback, carbon‐concentration feedback, CMIP6, SSP5‐3.4‐OS, overshoot, Environmental sciences, GE1-350, Ecology, QH540-549.5
More Details: 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.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 2328-4277
Relation: https://doaj.org/toc/2328-4277
DOI: 10.1029/2020EF001967
Access URL: https://doaj.org/article/8fe9ed0d8a874230b8949a6e393c7a02
Accession Number: edsdoj.8fe9ed0d8a874230b8949a6e393c7a02
Database: Directory of Open Access Journals
More Details
ISSN:23284277
DOI:10.1029/2020EF001967
Published in:Earth's Future
Language:English