Impact of evolving greenhouse gas forcing on the warming signal in regional climate model experiments

• Published in: Nature communications Vol. 9; no. 1; pp. 1304 - 7
• Main Authors: Jerez, S., López-Romero, J. M., Turco, M., Jiménez-Guerrero, P., Vautard, R., Montávez, J. P.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 03.04.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 704/106/694/1108; 704/106/694/2739; Air temperature; Atmospheric models; Carbon dioxide; Climate change; Climate models; Computer simulation; Continental interfaces, environment; Evolution; Global warming; Greenhouse effect; Greenhouse gases; Humanities and Social Sciences; multidisciplinary; Nitrous oxide; Ocean, Atmosphere; Reproducibility; Science; Science (multidisciplinary); Sciences of the Universe; Temperature; Trends
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-03527-y

Variations in the atmospheric concentrations of greenhouse gases (GHG) may not be included as external forcing when running regional climate models (RCMs); at least, this is a non-regulated, non-documented practice. Here we investigate the so far unexplored impact of considering the rising evolution of the CO 2 , CH 4 , and N 2 O atmospheric concentrations on near-surface air temperature (TAS) trends, for both the recent past and the near future, as simulated by a state-of-the-art RCM over Europe. The results show that the TAS trends are significantly affected by 1–2 K century −1 , which under 1.5 °C global warming translates into a non-negligible impact of up to 1 K in the regional projections of TAS, similarly affecting projections for maximum and minimum temperatures. In some cases, these differences involve a doubling signal, laying further claim to careful reconsideration of the RCM setups with regard to the inclusion of GHG concentrations as an evolving external forcing which, for the sake of research reproducibility and reliability, should be clearly documented in the literature. The inclusion of greenhouse gas forcing in regional climate model experiments is a non-regulated, non-documented practice. Here, the authors demonstrate the significant of the impact of this lack of regulation on simulated regional warming trends, which can double climate change signals under 1.5 °C global warming.