The US absolutely should reduce it's per-capita oil use/CO2 production, that much is true. But as far as scalability, it is the most scalable solution. In 1970,

The US absolutely should reduce it's per-capita oil use/CO2 production, that much is true. But as far as scalability, it is the most scalable solution. In 1970, US population was 205 million, and birth rate was below replacement. If there had been 0 immigration in the intermediate time, the population would have shrunk. Compared to current population, the total CO2 emitted would be less than 63% of current levels - a reduction by almost half. This could be applied to any country, and it could scale to go as low as needed.