Cutting human carbon dioxide emissions in half

That 1/2% of the world's GDP = gross domestic product can halve human carbon dioxide emissions seems very improbable to me. (professor John Schellnhuber claims) I presume the USA could pay the French one trillion dollars to build 100 gigawatts of nuclear reactors in USA. The French might even work a bit cheaper and complete the last plant within 20 years. In the meantime USA can start design of both fusion and fission nuclear plants, with the first pilot plants in ten years if the USA does better than usual. The French have designs which are proven reliable, safe and cost effective. The old USA designs were not cost effective, and the teams that built them are now past retirement age, so the USA is close to starting from scratch to build nuclear power plants. I don't know how to build a nuclear powerplant: Do you? With some tax payer money we can keep most of the 100 nuclear power plants built long ago in the USA pumping out gigawatts for perhaps another ten years.
We can do a bunch of things that will produce far less carbon dioxide reduction for another trillion dollars, mostly in the conservation area. Many of them we have done already, so throwing money at them will cause puny additional reductions.
I have not seen any detail for capturing carbon dioxide at the point where it is emitted by human activities. Has anyone heard a plan that will work large scale at a reasonable cost? or even at an unreasonable cost?
We can put photovoltaic panels and solar power towers in locations like New Mexico and Arizona which can supply half price electricity to the inhabitants of these locals, at huge cost to the federal tax payers. We can give big incentives to people to leave Northern cities likely to be buried under a mile of ice in a new ice age, and incentives to people of low lying locals to move to New Mexico and Arizona (which have good potential for solar energy) if the lowlands are flooded due to delay in the coming ice age. We know how to build oil platforms at sea in 200 feet of stormy water, so we can build simular structures on dry land in Florida and other low lying locals with a 10 story buildings that starts hundreds of feet above what may be the ocean bottom in a few years. These programs will spend more than 1/2 percent of the USA GDP without building more windmills which is the only other near term thing the USA can do as far as I know. Hydrogen is punny, electric vehicles are puny for the coming decade, perhaps forever.
Obviously Canada is in a far worse shape if new ice age covers all of Canada as far as mitigating possible effects. Most other countries have costs simular to the USA, many with far less GDP to apply to solutions.
The USA has not deforested. At huge cost we could increase forests in desert areas. We could perhaps offer long term visas to people likely to cut forests in other countries. Short of that, I see no practical way to prevent them from deforesting. Please give details of how we can reduce carbon dioxide emissions, as conservation is a puny solution and/or extremely costly. Even if we think doubling human carbon dioxide emissions will cause no problems, we should consider possible solutions as a contingency plan. Neil