This is cute. The "scientific" side of the debate is arguing about how things are going to be 1000 years from now.
Take any point in human history, look at that points predictions for what humanity would look like in 1000 years and see how reliable anything "in a 1000 years" looks.
Ludicrous.
Why is this ludicrous... people don't care, so they'll keep on pumping massive amounts of CO2 into the atmosphere. At 2ppm/year of CO2 increase, this will result in about 2,500 ppm of CO2 after 1,000 years.
There is no known cause which would reduce this rate of increase. There's a lot to say that the rate of 2ppm/year will actually increase over time, but let's ignore that as well to be on the safe side and not give any fodder to people like you to comment on. So let's not go into speculation about anything, let's work with what we know now, and all we know now is that we increase CO2 by 2ppm/year.
We can then look back to earth's past. When was the last time such levels of CO2 were reached... well... hey ... the Triassic!
What do we know about the Triassic... well it was hot. No glaciation anywhere. Some would blame this on Pangea... but even with Pangea you'd have polar icecaps and glaciers on mountains. There would be ice somehwere, it would be cold in the northern and southern regions... but it wasn't cold. There were subtropical forests growing at mid-latitudes for crying out loud.
This is hardly science. There's no real modelling involved about processes that might happen. It's a very very conservative thing about what might happen. And what might actually happen.
Now, the next thing is, if that's going to be the case, if there's no ice anywhere, then what kind of world would we have... well all the ice from Greenland and from Antarctica will have melted away! This will add 60 meters of water everywhere. Temperatures will be higher, which increases the water level even more... I don't know how much, but I suppose 40 meters would be an underestimation. That would mean, that global sea levels would've risen 100 meters.
My country, the Netherlands, is for the most part at or even below current sea level. Add 100 meters to that and my country will have disappeared under 100 meters of water.
This will almost certainly happen in 1,000 years if we continue exactly as we are doing now.
This brings me to the next point... responsibility. Should we blame the last generation for all that water and temperature increase? Or are we also partly to blame. I think we share the blame as well.
That means, in 1000 years from now, we'll be to blame for 1 meter of sea level rise and 0.1 degree of temperature increase for every decade that we continue like we are doing now.
This is called linear interpolation... which is also one of the safest interpolation you can make, because you make no assumptions. You could be wrong, but at least you won't have made an assumption which could be wrong too.
Now... this in itself doesn't mean that the sea level will really rise by 1 meter every decade. Who knows, maybe it will start slowly and maybe there will be some catastrofic melting and flooding later on. But that's not really the point... for future generations 1000 years from now, we are sharing responsibility for such things.
And I'm not young, I'm 42 years old and I've had a solid scientific education in geophysics. Although I didn't pursue that career, I became a programmer.
And I'm not saying that it will really happen in 1,000 years. I hope people will come to their senses before that. But given that the process is very gradual and people are pretty ignorant most of the time, maybe every generation will have this same discussion that we are having now, thinking that the present is "normal" and that the future is not their concern. So for all I know, a Triassic event might actually happen in 1,000 years.
And anyway this is not intended as a realistic future prediction. It's just that people don't believe in climate modeling and science. So this is the most basic example you can have, which you can easily understand and think about. It's as basic as it can get. You can draw your own conclusions from it.