Any such solution would require replacing trillions of dollars of plant and equipment and infrastructure with low-emissions alternatives, which takes many decad

Any such solution would require replacing trillions of dollars of plant and equipment and infrastructure with low-emissions alternatives, which takes many decades at the normal replacement rate of capital assets. It can't be done much faster than that no matter how hard we tried. There are no instant solutions. Emissions versus personal income follows a power law, so getting the top 10 percent to reduce their consumption to the global average would solve 60 percent of the problem. 800 million is less than billions.