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.
I disagree. Fossil fuels are not running out any time soon and their importance is just as high as it ever was. For example in Iran it is estimated to have 300+ more years of fossil fuels for both domestic use and exports but in somewhere like US they estimate to have less than 5 years of fossil fuels left.
The crisis you see is mostly local and it is due to bad decisions and it is NOT because they didn't use renewable energies like the sun! But it is because they built their country based on what they didn't have!
Take Germany for example. They should have never become industrialized because they didn't have gas and other basic requirements in their industries themselves! In other words, for decades they kept building massive industries based on what they had to buy from abroad because they didn't have nowhere near as much of it as they needed!
The result was obvious and foreseeable: 30% of them are already claiming to be insolvent and are declaring bankruptcy while 60% of them claim they have so much problems that they too may become insolvent very soon. All because they can no longer import what their industries need.
Now imagine if Germany never built all those energy hungry industries and instead focused on what their own geography and resources allowed them to do. Today there would have not been any crisis in Germany!