I think energy, rather than wheat, will cause a third world war. Oil is slowly dying out. The importance of natural gas is starting to increase. And there is a very serious energy shortage in the world. We still cannot use the sun and we are turning to fossil fuels. Yes, we are very close to the third world war.
The so called energy crisis is a result of decades of mismanagement. Governments around the world were too early and enthusiastic to close down coal and nuclear power plants and jump on to the green bandwagon. Those who made the gradual progression (such as France) are still managing the crisis in a better way. It is countries such as Germany, who made the abrupt jump, are paying for their mistakes. On top of that, oil and gas companies are facing increasing hostility from the governments and they reduced the amount allocated for exploration and development of new fields. This has also contributed to the current shortage in a significant way.