I watched a science program about the future of earth, talking about how earth will be in the future, from the planet being 150 degrees celcius on average and unable to support life in something like 750,000 years, to the start of plants being unable to photosynthesise anymore in a much shorter time frame... One of the things that was mentioned is that in around 10,000 years all humans around the world will be the same colour.... I'm going to say that that is when racism will be no more, humans of that time ofcourse will find another way to hate each other
Humans will be long gone in 3/4 million years. If we haven't destroyed ourselves we'll have evolved into something completely different and been superceded. Of course it won't stop the sun heating up/expanding naturally as it uses up its fuel and thus all the planets surrounding it creating those conditions.
I'm always a bit wary of this 'unable to support life' thing and I reckon life is prevalent in far more of the universe than we imagine and able to cope with very extreme conditions. If you think about it the Earth was formed by bits of rock that had been floating around the frozen depths of space for untold lengths of time, yet still those building blocks of life survived and eventually managed to reproduce until it created the vast variety of life we see today, have seen in the past and will see in the future. All in a relatively short time frame cosmically speaking. So if those building blocks were around on the bits of rock that created this planet, it's highly likely they're on many others and thus the ability for life to be created remains throughout the cosmos if it just has the right conditions to do so.
The important thing for life beyond anything else is stability. Conditions need to be consistent enough for a long enough period of time for those building blocks to adapt and thrive. If the conditions change too much too quickly anything created won't have enough time to gain a foothold. That is why the atmosphere is so important to us - it regulates our conditions.
I'm not convinced either about water is the vital thing for life - it's purely the medium which was available on this planet and was therefore what it adapted to. If we were further toward or away from the sun other elements could take the place of water in the meteorological cycle. Titan I think has one based around methane which is solid, liquid and gas at those cold temperatures. Provide the building blocks with a stable enough environment in those elements and they will, eventually, evolve to survive in them.
So I think as long as those changes are fairly slow paced and a planet has an atmosphere which provides it with enough stability life will be able to find a way of clinging on somehow. It may well be very simple forms of life, but it will be there.
Sadly, you're right about finding other reasons to hate each other. We already do to varying extents. Nationality, regions all artificial constructs. Beliefs, be they religious or political. There will be animosity based upon wealth. Some people hate others on gender, sexuality, even the brands they like.