We would depend more on them, and if a plauge wipes out all our crops history would repeat itsel again.
What if the earth suddenly stopped spinning but our atsmosphere coutinued at it's current speed?
Well the wind would be pretty devastating, however the real killer for planet Earth will be the thing that, since it stopped spining, the seasons and temperature would go completly haywire, leading to so many concequences I won't have the space to say them all.
What if the British, French, Partugese, Spanish and Russians leave the Americas alone and never colonize them?
The world would still be screwed up.
What if jacob1 actually was not a potato?
The rest of the world would feel left out and blow up Earth with lots of nukes.
What if, during WW2, Hitler realizes that invading Russia is a terrible idea and Nazi Germany never attacks the USSR?
The war would have lasted for a longer period of time, possibly ending with the use of nuclear weapons against both Japan and Nazi Gernany.
What if radioactivity and nuclear physics had been discovered a century earlier, instead of during the buildup to the two world wars?