  Dust is an essential ingredient of galaxies, determining the physical and
chemical conditions in the interstellar medium. Several complementary
observational evidences indicate that the cosmic dust mass density
significantly drops from redshift $z=1$ to $z=0$. Clearly, and for the first
time during cosmic evolution, dust must be destroyed more rapidly than it is
formed. By considering the dust production/destruction processes acting in this
cosmic time lapse, we find that the drop can be explained if dust is mainly
destroyed by astration (49\% contribution in the fiducial case) and supernova
shocks within galaxies (42\%). Our results further imply that on average each
supernova destroys only $M_{d,sn} =0.45\, M_\odot$ of dust, i.e. $5-10$ times
less than usually assumed, with a hard upper limit of $M_{d,sn} < {3.0}
M_\odot$ set by the available metal budget and maximal grain growth. The lower
efficiency might be explained by effective shielding of dust against shock
processing in pre-supernova wind shells.
