摘要：Based upon sensitivity experiments, this study aims to investigate the impact of increased atmospheric
CO2 concentration, climate changes, and ongoing technological advancements on bean (Phaseolus
vulgaris) and maize (Zea mays) yield. This investigation assumes that the atmospheric
CO2 concentration evolves according to the A2 scenario. For these analyses we have used climate
data as projected by climate simulations conducted with the HadCM3 climate model for both
present day and greenhouse warming conditions. The results demonstrated that warming
conditions associated with increased greenhouse gases as delivered by the HadCM3 model
lead to reductions in the potential productivity of maize and beans for the years 2050 and
2080 by up to 30%. This thermal response is, however, damped by the highly efficient
CO2 fertilization effect which is expected to increase bean productivity as compared to present day
conditions. A similar investigation for maize yield revealed a different picture. It has been found that
the CO2 fertilization feedback is much weaker and cannot cancel out the thermal effect. We have
found, therefore, that climate changes as simulated to occur in the future are not favorable
for increasing the maize yield in southeast Brazil. By the inclusion of the third
forcing evaluated, representing technological advancements, it is demonstrated
that improvements in the crop system reduce the negative effect associated with
warmer climate conditions for both crops. We conclude that appropriate soil and
technological management as well as genetic improvements may very likely induce an
increase in bean and maize yield despite the unfavorable future climate conditions.
