  We model disorder in graphene by random impurities treated in a
coherent-potential approximation. Using the analytically solvable Lloyd model
for the disorder distribution, we show that the temperature dependence of the
minimum conductivity as well as the temperature dependence of the resistivity
at high densities and the density dependence of the respective slopes are
consistently explained by a temperature dependent disorder strength $\Gamma$
consisting of a constant plus a $T$-linear contribution. This finding suggests
that at least two contributions to scattering in graphene are important for its
transport properties, and that one of the contributions is due to scattering of
electrons from thermally induced excitations.
