[cjbenedikt]

You can combine it with H2 to produce synthetic fuels. Not ideal but could reduce fossil fuel use and hence new CO2 released.

[HPsquared]

Third ingredient missed out: lots of energy.

[nkmnz]

The reaction of 3 H2 + CO2 -> CH3OH + H2O is exergonic, so the H2 already brings all the energy needed.