What are some of the issues that create conflict in the future and why?

Some of the reasons for future conflict between nations could be:

Explanation:

1: water wars, this is something possibly brewing between Ethiopia and Egypt with Sudan being on Ethiopia's side as the dam Ethiopia plans to build which would take a lot of Egypt's water would also power Sudan with electricity. Oh and something frightening could happen as China is damming India's major rivers which could lead to a world war or India becoming a Chinese vassal and massive amounts of displaced and starving people either way.

2: a global economic drop: this will severely impact the economies of many countries, especially countries in the middle of industrialization in Africa which are very fragile, I will give it a few decades to fully blow up there.

3:Competing interests, ethnic and international for example in Central Asia there are a lot of competing influences and something could happen there but thing is wars because of what I just mentioned are already happening, look at Syria with the "moderate" rebels, between Armenia and Azerbaijan we have had a conflict which had several geopolitical implications and reasons it went as it did, currently Libya is in a proxy war too, and recently Ethiopia has had conflicts within a Northern region which are heavily ethnic-based and could lead to an Ethiopian civil war if the government does not manage to solve this, which would also mean the first war I mentioned would be delayed or prevented trough another bloody war.

4: an incident: many wars have started because of incidents escalating, so watch out for it, for example earlier this yea- oh it's been a year already since Qasem Soleimani was assasinated , however luckily nothing happened then.

Either way we're gonna have more wars before world peace and mercenaries are becoming more popular like Turkey and more countries are using in proxy wars and another thing you should watch out for is the first use of robots in war and hope that they distinguish between regular humans and soldiers and don't commit atrocities, happy 2021!