Due to the lapse in federal government funding, NASA is not updating this website. We sincerely regret this inconvenience. Go to Main Content (Accesskey 2)Go to Site Menu (Accesskey 3) National Aeronautics and Space Administration Goddard Institute for Space Studies Goddard Space Flight CenterSciences and Exploration DirectorateEarth Sciences Division Research Features Wallace Broecker and GISS By Allegra LeGrande, David Rind, Dorothy Peteet, and Gavin Schmidt – March 2019