Writers : That 's not possible if we maintain the status quo , much less bring online more and exceedingly dirty sources of fuel such as tar sands oil . Review of Keystone XL pipeline information shows it 's not in the national interest . They say tar sands oil spews 17 % more greenhouse gas than crude oil refined in the U.S . Writers : The U.S. is a net exporter, so why would we want to export our carbon emissions? Oil companies will need even more pipelines to reach their goals , they say .
Writers : Review of Keystone XL pipeline information shows it 's not in the national interest . They say tar sands oil spews 17 % more greenhouse gas than crude oil refined in the U.S . Writers : The U.S. is a net exporter, so why would we want to export our carbon emissions? Oil companies will need even more pipelines to reach their goals , they say .