  In this work we investigate the impact of calculating non-equilibrium
chemical abundances consistently with the temperature structure for the
atmospheres of highly-irradiated, close-in gas giant exoplanets. Chemical
kinetics models have been widely used in the literature to investigate the
chemical compositions of hot Jupiter atmospheres which are expected to be
driven away from chemical equilibrium via processes such as vertical mixing and
photochemistry. All of these models have so far used pressure--temperature
(P-T) profiles as fixed model input. This results in a decoupling of the
chemistry from the radiative and thermal properties of the atmosphere, despite
the fact that in nature they are intricately linked. We use a one-dimensional
radiative-convective equilibrium model, ATMO, which includes a sophisticated
chemistry scheme to calculate P-T profiles which are fully consistent with
non-equilibrium chemical abundances, including vertical mixing and
photochemistry. Our primary conclusion is that, in cases of strong chemical
disequilibrium, consistent calculations can lead to differences in the P-T
profile of up to 100 K compared to the P-T profile derived assuming chemical
equilibrium. This temperature change can, in turn, have important consequences
for the chemical abundances themselves as well as for the simulated emission
spectra. In particular, we find that performing the chemical kinetics
calculation consistently can reduce the overall impact of non-equilibrium
chemistry on the observable emission spectrum of hot Jupiters. Simulated
observations derived from non-consistent models could thus yield the wrong
interpretation. We show that this behaviour is due to the non-consistent models
violating the energy budget balance of the atmosphere.
