  We generalize a notion of 'conserved' charges given by Wald and Zoupas to the
asymptotically de Sitter spacetimes. Surprisingly, our construction is less
ambiguous than the one encountered in the asymptotically flat context. An
expansion around exact solutions possessing Killing vectors provides their
physical meaning. In particular, we discuss a question of how to define energy
and angular momenta of gravitational waves propagating on Kottler and Carter
backgrounds. We show that obtained expressions have a correct limit as $\Lambda
\to 0$. We also comment on the relation between this approach and the one based
on the canonical phase space of initial data at $\mathcal{I}^+$.
