Originally posted by KazetNagorra
Just looking at the effect of rising sea levels on coast lines is pretty straightforward and is something you could calculate with your smartphone, given a height map of the Earth. I wouldn't know of any user-friendly application that would show the result, though.
Calculating the effect of changing temperature is extremely difficult.
Actually it's not strait forward at all.
Factors that make it not straightforward...
You need an accurate ground level map, unfortunately the satellite radar used to create such maps
has problems with buildings, trees, and certain ground types where the radar can penetrate a way in
and then reflect. All of which cause accurate maps of ground level to be hard to come by and expensive.
You can get greater accuracy by aerial/ground surveys, but they are even more expensive.
You need to factor in not just the hight of the ground, but if there is a path for the sea water to reach
any given area. There are areas that would be underwater right now if there were not sea defences holding
the water back. And low lying areas with hills/mountains between them and the sea.
Making a model that can account for this is much harder and more computationally intensive than simply
checking the hight [which has an error margin to go with it].
On top of that you have two more problems.
First being that some ground types allow water to permeate through them, and so if the sea level rises
high enough, some inland areas could start to flood even without a direct link to the sea.
Second, it's hard to predict if or when certain sea defences might be breached [or built] as we defend
ourselves from rising seas.
Sea level rise is not uniform. All the maps linked to so far assume uniform sea level rise over the entire
ocean. However, as the ice sheets melt they loose mass and thus loose gravitational pull.
This causes the oceans to slump away from the ice sheets as they become less attracted to them.
This effect is large enough that if you were to simply melt the Greenland ice sheet, some places in
Greenland and northern America would have sea level drops not rises. Obviously to compensate
other places, mainly southern hemisphere, would have much larger sea level rises.
It gets much more complicated when you factor in melting from both ice caps. Basically you need
to solve a computational model simulating the mass redistribution caused by the melting ice caps.
Which is not a trivial problem.
And these are just the problems I can think of off the top of my head.
This is why there is not an App for this yet.