Carbon Emissions

Increasing concentrations of atmospheric carbon dioxide (CO2) gas resulting from anthropogenic activities generates concern for possible changes in global climate. In 2005, global atmospheric CO2 concentration reached nearly 380 parts per million (ppm), which is equivalent to 805 Pg C (1 Pg = 1 petagram = 1015 g) from a preindustrial (1850) concentration of about 280 ppm. An increase in atmospheric CO2 concentrations to 450–600 ppm from current levels over the coming century will have an irreversible effect, including rainfall reductions in subtropical areas and an unprecedented rise in sea level, leading to the inundation of small islands and low-lying coastal areas. The United States is the largest single national source of fossil-fuel-related CO2 emissions—1,577 million metric tons of carbon (MMTC)—followed by China (1,514 MMTC), ...