How will these broad GEC conditions be expressed on the small scale in particular locations? What will the consequences be for organisms (crop plants and animals and species of fish etc.) required by human beings? How will pests, diseases and weeds respond to changes in particular environmental conditions? How important will individual physico-chemical and biological factors be, alone and in interaction? The potential effects can be judged at the agricultural scale from what is already established in much scientific work. This chapter examines what is known of the effects of global environmental change on crops, animals and fisheries and what is likely to happen over the next century or so, and suggests possible remedies.