Warming Hole (2 of 2) (IMAGE) Harvard University Caption This map illustrates the observed change in surface air temperature between 1930 and 1990. Observations are from the NASA GISS Surface Temperature Analysis. Credit Image courtesy of Eric Leibensperger Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.