ABSTRACT

Increases in average ambient temperature and CO₂ levels, as predicted by researchers studying climate change, may potentially affect agricultural production levels and the suitability of regions for specific crop production. The crop simulation model, GOSSYM, was used to examine the impact of changes in these two variables on yield and irrigation requirements of cotton produced at nine locations across the U.S. cotton belt: Shafter, CA; Maricopa, AZ; Artesia, NM; Lubbock TX, Corpus Christi, TX; Portageville, MO; Stoneville, MS, Meridianville, AL, and Florence SC. Average net returns were calculated for each location, under two potential climate regimes, one based on historic weather patterns and one based on patterns predicted by a regional climate model (Mearns, 2000). Under each regime, the interaction of five changes in average temperature and five changes in carbon dioxide level were evaluated. The ranges chosen for changes in temperature and CO₂ levels reflect conditions from the pre-industrial era to the limit of accepted scientific predictions for climate change.

While results were specific for each location, some general trends are that, ceteris paribus, as CO₂ level increased, production improved and net returns increased. However, yield and net returns results under the regional climate model’s predictions of future climate generally had lower magnitude yield and net returns than those under present climate at all levels of atmospheric CO₂ and temperature deviation. Thus future climate conditions had a negative effect on yield and net returns at most locations. No clear trend emerged on the effects of temperature increases on yield and net returns.