Government attention and policy implementation are important for achieving environmental goals. This study uses 257 cities in China from 2013-2019 as the sample and measures local government attention through text mining, thus exploring the carbon emission reduction effect of government attention. Threshold regression is further used to examine the role and nonlinear relationship that environmental policies assume in the effect of government attention on carbon emission reduction. The conclusions are as follows: first, government attention can significantly reduce carbon emissions: with a 1% increase in local government attention to environmental protection, China's urban CO2 can be reduced by 0.04%. Second, the impact of government attention on carbon emissions is more significant in cities in non-air pollution prevention areas, in non-SO2 and acid rain control areas, with longer tenure of officials, and with female officials serving during the sample period. Third, the effect of government attention on carbon emission reduction can be significantly increased under policy influence, especially when two policies are implemented in concert. Fourth, market incentive policies play a stronger role in the first place, while traditional energy-saving policies have strong sustainability. In general, the study concludes that municipalities should allocate more attention to the environment, and it gives some reasons supporting policy choices.