This is a list of countries by estimated carbon emissions 2012. As the list reveals, China stands for the largest part of worlds carbon emissions followed by the United States and India. Note that Chinas carbon emission per capita isn't larger than about a third of the corresponding figure for the United States and that India's carbon emission per capita is as low as about a tenth of the same. These two countries alone are home for about 2.6 billion people today. It is hard to even imagine what the consequences these countries could cause the climate in the future if their carbon emission per capita reaches the same levels as in the United States.  

Related lists:  Countries by Carbon Dioxide per Capita, Global greenhouse gas emission by source