Technical Abstract: In order to determine the likely effects of the increasing atmospheric CO2 concentration on the physiology, growth, yield, water use, and soil carbon sequestration of plants under open-field conditions, free-air CO2 enrichment (FACE) experiments have been conducted at several locations around the world. Results from these several studies are being compiled in a book edited by Swiss researchers. This paper is a book chapter that provides an overview of the results from FACE experiments conducted at Maricopa, Arizona, USA, on cotton, wheat and sorghum. Briefly, the cotton had a large growth and yield response to the elevated CO2 concentrations with no significant change in water requirements. Sorghum had no significant change in growth or yield at ample water supply, and wheat was intermediate between cotton on sorghum. In contrast, when water was in short supply, both wheat and sorghum had larger growth and yield responses to elevated CO2. Under the ample water supply, both sorghum and wheat had a reduction in their water requirements. Because atmospheric CO2 levels continue to rise globally, this research is important for helping to develop strategies to maximize the benefits and minimize the detriments to agricultural productivity, which will benefit producers and consumers of food and other agricultural products worldwide.