Abstract Are winters getting warmer.pdf

ARTICLE IN PRESS DTD 5 /locate/envsoft Environmental Modelling Software -- (2004) ---–---Are winters getting warmer? Timothy J. Vogelsanga,),1, Philip Hans Fransesb aDepartment of Economics, Uris Hall, Cornell University, Ithaca, NY 14853-7601, USA bEconometric Institute, Erasmus University Rotterdam, P.O. box 1738, NL-3000 DR Rotterdam, The Netherlands Received 18 December 2003; received in revised form 4 June 2004; accepted 24 September 2004 Abstract We examine whether any trends in monthly temperatures are the same through-out the year for various lengthy series. The data concern the world, the northern and southern hemispheres, and about three centuries of data for the United Kingdom and the Netherlands. For the empirical exercise, we rely on new and accurate tests which have been recently developed. These tests do not have standard distributions, so that critical values have to be tabulated. The empirical findings include significant worldwide temperature increases, differences across months for the northern hemisphere, and warming winters for the UK and the Netherlands.
2004 Elsevier Ltd. All rights reserved. Keywords: Deterministic trends; Hypothesis testing; Monthly temperatures1. Introduction There seems to be a consensus amongst scientists and politicians that temperatures on Earth are systematically on the rise. Depending on the type of data, the degree of aggregation, and the statistical method used, a general finding is that annual temperature series going back to the mid 1800’s display positive upward trends, see Bloomfeld (1992), Fomby and Vogelsang (2002), Wood- ward and Gray (1993), and Zheng and Basher (1999), while Singer (2001) provides an alternative view based on more recent data. A question that is rarely addressed concerns whether the increase in temperatures is the same across the months. Indeed, if there is seasonal variation in warming, or perhaps if there is cooling in some months, one may want to re-address theoretical explanations fo