We thank J. Baehr, S. G. H. Philander, R. S. J. Tol, and three anonymous reviewers for helpful feedback. Any remaining errors are, of course, attributable to the authors. Special thanks go to R. Stouffer for providing the GFDL model results and for valuable discussions. This study was partially supported by the National Science Foundation (SES 0345925). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. We gratefully acknowledge additional support from the Carbon Mitigation Initiative at Princeton University and the Environmental Consortium at the Pennsylvania State University.
This paper is dedicated to the memory of David F. Bradford.
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