re: 1/10th refers to per-capita emissions
China's population is reportedly about 1.3 billion people. India's population is over 1 billion. The US population is approximately 280 million. If your figure of 1/10th per capita emissions is accurate, that means that the total emissions of China and India together is already about 82% of the US and is growing rapidly while US emissions are reportedly flat or even declining slightly. You can't just look at a snapshot at time, you have to look at the trend lines.