Good set of questions there and here are mine...

If there was no gas and electricity for a long time, how did it all get started back up again? I mean, how was steel prepared for fabricating industrial equipment to drill for oil, crackers etc to change oil to petrol, without a fuel supplied oil or electric smelter?

How was foodstuff transported?

What was the population of the US, Europe or the world in 2040?
If you know then how do you know?

Did the war progress to many other nations worldwide or was it confined to a central location (Middle East) with only the participants you mentioned?

Did France give up easily and let Britain bale them out again?

What countries or continents were unaffected by the war?

Did these countries or continents have there own regional problems such as drought, famine, internal strife etc?