Warming Hole (1 of 2) (IMAGE) Harvard University Caption This figure illustrates the mean effect on surface temperature, during the period 1970-1990, of particulate pollution. The central region was cooled by as much as 1 degree Celsius. Credit Image courtesy of Eric Liebensberger 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.