  We present the evolution of the Cosmic Spectral Energy Distribution (CSED)
from $z = 1 - 0$. Our CSEDs originate from stacking individual spectral energy
distribution fits based on panchromatic photometry from the Galaxy and Mass
Assembly (GAMA) and COSMOS datasets in ten redshift intervals with completeness
corrections applied. Below $z = 0.45$, we have credible SED fits from 100 nm to
1 mm. Due to the relatively low sensitivity of the far-infrared data, our
far-infrared CSEDs contain a mix of predicted and measured fluxes above $z =
0.45$. Our results include appropriate errors to highlight the impact of these
corrections. We show that the bolometric energy output of the Universe has
declined by a factor of roughly four -- from $5.1 \pm 1.0$ at $z \sim 1$ to
$1.3 \pm 0.3 \times 10^{35}~h_{70}$~W~Mpc$^{-3}$ at the current epoch. We show
that this decrease is robust to cosmic variance, SED modelling and other
various types of error. Our CSEDs are also consistent with an increase in the
mean age of stellar populations. We also show that dust attenuation has
decreased over the same period, with the photon escape fraction at 150~nm
increasing from $16 \pm 3$ at $z \sim 1$ to $24 \pm 5$ per cent at the current
epoch, equivalent to a decrease in $A_\mathrm{FUV}$ of 0.4~mag. Our CSEDs
account for $68 \pm 12$ and $61 \pm 13$ per cent of the cosmic optical and
infrared backgrounds respectively as defined from integrated galaxy counts and
are consistent with previous estimates of the cosmic infrared background with
redshift.
