Recently there has been growing attention in the literature towards the
prospects of using future gravitational wave observations of inspiralling
compact binary systems as high-precision cosmological distance
indicators. These so-called "standard sirens" are the gravitational wave
analogues of "standard candles" and, when combined with measurement
of their redshift from their electromagnetic counterpart, could yield a
wholly independent calibration of the cosmological distance ladder and a
sensitive probe of cosmological parameters through construction of their
luminosity distance redshift relation.

An important issue with the cosmological application of standard sirens,
however, is the impact of weak gravitational lensing from intervening
large scale structure. For supermassive black hole (SMBH) sirens observed
with LISA, for example, gravitational lensing will randomly (de-)magnify
the gravitational wave signal, seriously degrading their performance as
cosmological probes.

In this seminar I will review the recent work on cosmological applications
of standard sirens, and present the results of our investigation into the
efficacy of "delensing" SMBH sirens using weak lensing maps - constructed
from ground- and space-based survey data - along each siren's line of
sight.