There is no current technology to remove greenhouse gases from the atmosphere on a scale that would make a big difference. The best that can be done now is to minimise future damage by stopping production of greenhouse gases, and planning for inevitable changes in the environment.
This leaves humanity with seemingly one option, to more or less "down tools", live locally, and accept a simpler life. A form of socialism is required, with basic income. And yes, we don't know how to pay for it either, although the fact that 5% of the population has 95% of the wealth suggests an obvious starting point.
Until humanity accepts that our current lifestyle is unsustainable, there can be no solution.
Remaining fossil fuel energy, if it is to be used at all, should be reserved for building infrastructure that will support a no-carbon community.