Most of what you mention is actually a problem solving itself. One of the cause of man made climate change is overpopulation, with most of the human population being crammed into megacities of which many are coastal it means the overpopulation will probably fix itself with people living in big cities mass dying. Big and not that big cities do not produce enough food and water for themselves, density of population means they will be hotspots for contagious diseases, means of transportation out of those cities do not allow for mass migration, all these and more means those people are likely to die.

On the other hand people living in the countryside, are able to grow food, have knowledge of local plants and generally can sustain themselves have much better chance to survive the catastrophic events to come.

Though some experts think a war over water between India and China is possible, other think the collapse will happen so fast that it will wipe all possibility of military action and leave only people that will have no choice but work together to survive. This scenario is also likely.

It's been a while since I've been in India but imho this is one the places on earth with potential to survive climate change.

I think the north eastern India, which has lot of forest cover and is close to Himalayas, might be able to sustain local population. Similarly, the islands which don't submerge my also do fine. But the real problem will be with coastal metros(esp. Mumbai) and with central India. I have quite some friends from central India, and the situation isn't good there. Already, this region receives much less rainfall than the coastal regions, as the two mountain ranges on both coasts block most clouds. Change in weather would very severely affect this region.

https://youtu.be/LJf5JjZjsGI have a look at this video, this region which suffered hailstorm destroying most crops, is supposed to be a somewhat dry region.

> When cities like Mumbai and Dhaka will start to submerge, you can imagine the havoc that will cause.

Actually, no, I can't. This won't happen overnight, cities will just slowly move away from the coastline. It will take hundreds of years to cover such cities with water (if ever).

Current estimations say this could happen around 2040-2050 and will happen before the end of the century. so not centuries but decades. And it will happen as the rise of sea level would not stop even if we stopped the increase of temperature instantly due to inertia.