Identifying trend reversals in atmospheric ethane from a multi-site analysis
Journal article, 2026
Ethane is the most abundant non-methane hydrocarbon in Earth’s atmosphere and acts as an indirect greenhouse gas, influencing the atmospheric lifetime of methane. Therefore, understanding the development of trends and identifying trend reversals in atmospheric ethane is crucial. Ethane abundance is measured at different ground-based stations worldwide using Fourier transform infrared remote sensing techniques. We compile a new dataset comprising 26 ethane time series from the Northern and Southern Hemispheres. We analyze their long-term trends using different econometric techniques capable of handling missing data and strong seasonal components present in the data. The resulting trend patterns are consistent across the different methods, with similar estimated trends at the various stations. In the Northern Hemisphere, the common trend across stations declined from the 1990s to 2005, gradually increased over the next decade, and then resumed a similar downward trajectory from 2015 onward. The estimated trends reveal a pronounced peak around 2014/2015, marking a reversal from an upward to a downward trend.
Atmospheric ethane
Nonparametric trend analysis
FTIR remote sensing
Kalman filter
Author
Marina Friedrich
Vrije Universiteit Amsterdam
Tinbergen Institute - TI
Siem Jan Koopman
Vrije Universiteit Amsterdam
Tinbergen Institute - TI
Yicong Lin
Tinbergen Institute - TI
Vrije Universiteit Amsterdam
E. Mahieu
University of Liège
Stephan Smeekes
Maastricht University
M. De Maziere
Belgian Institute for Space Aeronomy (BIRA-IASB)
Victoria A. Flood
University of Toronto
Matthias Max Frey
Karlsruhe Institute of Technology (KIT)
M. Grutter
Universidad Nacional Autónoma de México
J. W. Hannigan
National Center for Atmospheric Research
F. Hase
Karlsruhe Institute of Technology (KIT)
N. Jones
University of Wollongong
Rigel Kivi
Finnish Meteorological Institute (FMI)
M. V. Makarova
Saint Petersburg State University - Spsu
Isamu Morino
National Institute for Environmental Studies of Japan
Isao Murata
Tohoku University
Tomoo Nagahama
Nagoya University
J. Notholt
Universität Bremen
Ivan Ortega
National Center for Atmospheric Research
Maxime Prignon
Chalmers, Space, Earth and Environment, Geoscience and Remote Sensing
Amelie N. Röhling
Karlsruhe Institute of Technology (KIT)
Dan Smale
National Institute of Water and Atmospheric Research (NIWA)
K. Strong
University of Toronto
Yao Té
Pierre and Marie Curie University (UPMC)
Minqiang Zhou
Chinese Academy of Sciences
Climatic Change
0165-0009 (ISSN) 1573-1480 (eISSN)
Vol. 179 4 66Subject Categories (SSIF 2025)
Physical Geography
DOI
10.1007/s10584-026-04153-0