ESDD Earth System Dynamics Discussions ESDD 2190-4995 Copernicus GmbH Göttingen, Germany 10.5194/esdd-3-561-2012 Polynomial cointegration tests of anthropogenic impact on global warming Beenstock M. 1 Reingewertz Y. 1 Paldor N. 2 Department of Economics, the Hebrew University of Jerusalem, Mount Scopus Campus, Jerusalem, Israel Fredy and Nadine Institute of Earth Sciences, the Hebrew University of Jerusalem, Edmond J. Safra campus, Givat Ram, Jerusalem, Israel 16 07 2012 3 2 561 596 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.earth-syst-dynam-discuss.net/3/561/2012/esdd-3-561-2012.html The full text article is available as a PDF file from http://www.earth-syst-dynam-discuss.net/3/561/2012/esdd-3-561-2012.pdf

We use statistical methods for nonstationary time series to test the anthropogenic interpretation of global warming (AGW), according to which an increase in atmospheric greenhouse gas concentrations raised global temperature in the 20th century. Specifically, the methodology of polynomial cointegration is used to test AGW since during the observation period (1880–2007) global temperature and solar irradiance are stationary in 1st differences whereas greenhouse gases and aerosol forcings are stationary in 2nd differences. We show that although these anthropogenic forcings share a common stochastic trend, this trend is empirically independent of the stochastic trend in temperature and solar irradiance. Therefore, greenhouse gas forcing, aerosols, solar irradiance and global temperature are not polynomially cointegrated. This implies that recent global warming is not statistically significantly related to anthropogenic forcing. On the other hand, we find that greenhouse gas forcing might have had a temporary effect on global temperature.

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