  This paper is devoted to the proof of a global existence result for the water
waves equation with smooth, small, and decaying at infinity Cauchy data. We
obtain moreover an asymptotic description in physical coordinates of the
solution, which shows that modified scattering holds.
  The proof is based on a bootstrap argument involving $L^2$ and $L^\infty$
estimates. The $L^2$ bounds are proved in a companion paper of this article.
They rely on a normal forms paradifferential method allowing one to obtain
energy estimates on the Eulerian formulation of the water waves equation. We
give here the proof of the uniform bounds, interpreting the equation in a
semi-classical way, and combining Klainerman vector fields with the description
of the solution in terms of semi-classical lagrangian distributions. This,
together with the $L^2$ estimates of the companion paper, allows us to deduce
our main global existence result.
