Every generation has their war. A generation is 26-30 years. Just enough time for people to be born who haven't seen the horror of the last war. Also the wars are getting closer together as proxy wars don't have such a bad effect on people.
1915 - World War 1
1945 - World War 2
1975 - Vietnam War
2001 - War on Terror
c2025 - World War 5??
So I think WW5 will start in about 10 years time.
Some trends in the next 10 years:
Europe moving toward a new far right.
More economic collapses in Southern Europe.
Islamic countries uniting into a new superpower.
Russia becoming more powerful and aggressive.
China economic bubble could burst turning it rogue.
American far right antagonises Mexico.
Populations continuing to grow.
South America becoming stronger.
New Ebola type crisis.
When people in 2050 write their history essays about the cause of WW6 I think they will say that the trends were all ready there in 2015.
What do you think?