Stern's approach to discounting has been debated amongst economists. The discount rate allows economic effects occurring at different times to be compared. Stern used a discount rate in his calculation of the effects of "business-as-usual" climate change damages. A high discount rate reduces the calculated benefit of reducing greenhouse gas emissions. Using too low a discount rate wastes resources because it will result in too much investment in cutting emissions (Arrow "et al.", 1996, p. 130). Too high a discount rate will have the opposite effect, and lead to under-investment in cutting emissions. Most studies on the damages of climate change use a higher discount rate than that used in the Stern Review. Some economists support Stern's choice of discount rate (Cline, 2008; Shah, 2008 Heal, 2008) while others are critical (Yohe and Tol, 2008; Nordhaus, 2007).