Joshua Abbott, Arizona State University (IMAGE) Arizona State University Caption Arizona State University economist and sustainability professor Joshua Abbott says that without putting a dollar value on natural capital it cannot be measured against other assets and expenses. Credit Arizona State University 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.