  Accurate determination of photospheric solar abundances requires detailed
modeling of the solar granulation and accounting for departures from local
thermodynamical equilibrium (LTE). We argue that the forbidden C I line at 8727
A is largely immune to departures from LTE, and can be realistically modeled
using LTE radiative transfer in a time-dependent three-dimensional simulation
of solar surface convection. We analyze the [C I] line in the solar flux
spectrum to derive the abundance log epsilon(C)= 8.39 +/- 0.04 dex. Combining
this result with our parallel analysis of the [O I] 6300 A line, we find
C/O=0.50 +/- 0.07, in agreement with the ratios measured in the solar corona
from gamma-ray spectroscopy and solar energetic particles.
