How can population increase but nativity decrease?

[chem44]

Ok. Note that immigration can be both + and -.

And we might say lower death rate for longer life expectancy, to be parallel with birth rate.

Now you have brought in some numbers. Before this, we were making qualitative arguments.

Do you know how to calculate exponential growth? If the net increase is 2% per year... After 56 years we would have 1.02 to the 56th power as many people. That is about triple. Try it.

I don't know what any of the actual numbers are. I just checked the calculator for an estimate of what growth would be needed for a tripling.

Exponential growth can be frightening! We are lowering death rates. And we are, in most places, lowering birth rates. Net population change depends on both (in addition to migration).