Kevin J Anchukaitis, University of Arizona, Tucson, AZ, United States, Allegra N. LeGrande, NASA GISS 568, New York, NY, United States, Francis Ludlow, Harvard University, Cambridge, MA, United States, Michael Sigl, Paul Scherrer Institut, Laboratory of Environmental Chemistry, Villigen, Switzerland, Matthew Toohey, GEOMAR, Kiel, Germany and Celine Marie Vidal, University of Cambridge, Cambridge, United Kingdom