| Title: |
Inherent uncertainty disguises attribution of reduced atmospheric CO 2 growth to CO 2 emission reductions for up to a decade |
| Authors: |
Spring, Aaron; Ilyina, Tatiana; Marotzke, Jochem |
| Contributors: |
Bundesministerium für Bildung und Forschung; Horizon 2020 Framework Programme |
| Source: |
Environmental Research Letters ; volume 15, issue 11, page 114058 ; ISSN 1748-9326 |
| Publisher Information: |
IOP Publishing |
| Publication Year: |
2020 |
| Description: |
The growth rate of atmospheric CO 2 on inter-annual time scales is largely controlled by the response of the land and ocean carbon sinks to climate variability. Therefore, the effect of CO 2 emission reductions to achieve the Paris Agreement on atmospheric CO 2 concentrations may be disguised by internal variability, and the attribution of a reduction in atmospheric CO 2 growth rate to CO 2 emission reductions induced by a policy change is unclear for the near term. We use 100 single-model simulations and interpret CO 2 emission reductions starting in 2020 as a policy change from scenario Representative Concentration Pathway (RCP) 4.5 to 2.6 in a comprehensive causal theory framework. Five-year CO 2 concentration trends grow stronger in 2021–2025 after CO 2 emission reductions than over 2016–2020 in 30% of all realizations in RCP2.6 compared to 52% in RCP4.5 without CO 2 emission reductions. This implies that CO 2 emission reductions are sufficient by 42%, necessary by 31% and both necessary and sufficient by 22% to cause reduced atmospheric CO 2 trends. In the near term, these probabilities are far from certain. Certainty implying sufficient or necessary causation is only reached after, respectively, ten and sixteen years. Assessments of the efficacy of CO 2 emission reductions in the near term are incomplete without quantitatively considering internal variability. |
| Document Type: |
article in journal/newspaper |
| Language: |
unknown |
| DOI: |
10.1088/1748-9326/abc443 |
| DOI: |
10.1088/1748-9326/abc443/pdf |
| Availability: |
https://doi.org/10.1088/1748-9326/abc443; https://iopscience.iop.org/article/10.1088/1748-9326/abc443; https://iopscience.iop.org/article/10.1088/1748-9326/abc443/pdf |
| Rights: |
http://creativecommons.org/licenses/by/4.0 ; https://iopscience.iop.org/info/page/text-and-data-mining |
| Accession Number: |
edsbas.11125745 |
| Database: |
BASE |