It will depend to several factors. For instance, global warming in cool araes can be usefull for crop production but it has more destructive effects in warm and arid zones. Moreover, C3 crops usually more affected from warming than C4 crops and...
For avoiding the destructive effects of global warming:
1)Human activities that generate green house gases must be deminished and stoped!
2)Research on following aspects:
ecological and agro-ecological effects of warming must be deeply understood!
new crops with high production potential under heat and drought stresses must be investigated.
increasing the potential of crop plants by genetic improvement
increasing the efficiency of irrigation especially in developing countries
restricting the development of deserts and soil salinity esp. in arid zones