Bloomberg proposes a
megaproject
to protect New York from the effects of global heating, for a few
decades.
However, by the end of this century it
may
need to be surrounded by levees, as New Orleans is today. And so
will Newark, Boston, DC, and many other US coastal cities. And you'd
be crazy to live in them if you had any choice.
It would be cheaper to launch a national crash program for renewable energy
and then lead the rest of the world. Shanghai will be in the same boat and
likewise in danger of being swamped; when the Chinese rulers realize that,
they will do whatever it takes, if the US is with them.