  We investigate the impact of the intracluster medium on the weak-lensing
shear power spectrum (PS). Using a halo model we find that, compared to the
dark matter only case, baryonic pressure leads to a suppression of the shear PS
on the order of a few percent or more for $l \gtrsim 1000$. Cooling/cooled
baryons and the intergalactic medium can further alter the shear PS. Therefore,
the interpretation of future precision weak lensing data at high multipoles
must take into account the effects of baryons.
