“In 2013 the level of U.S. farm output was about 2.7 times its 1948 level, and productivity was growing at an average annual rate of 1.52%. From 2001 to 2013, world-wide, global output of total crop and livestock commodities was expanding at an average rate of 2.52% a year[…] Along with better plant varieties, cropping practices and fertilizer, CO2 has contributed to this welcome increase in productivity.”