Temperature effect by ballpark (IMAGE) Dartmouth College Caption Increase in average number of home runs per year for each American major league ballpark with every 1-dgree Celsius increase in global average temperature. Credit Christopher Callahan Usage Restrictions N/A License Original 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.