A new study published in Nature Climate Change says that building the Keystone XL pipeline could cause as much as four times the amount of greenhouse gas emissions as previously estimated.
In February, the State Department released its environmental impact statement on Keystone XL, estimating that the pipeline could increase emissions of the heat-trapping gases by 1.3 million to 27.4 million metric tons each year, the Los Angeles Times reports. The new study estimates it could be as high as 100 million to 110 million metric tons every year.
"The sole reason for this difference is that we account for the changes in global oil consumption resulting from increasing oil sands production levels, whereas the State Department does not," write authors Peter Erickson and Michael Lazarus, scientists with the Stockholm Environment Institute.
The $5.3 billion pipeline would stretch from Hardisty, Alberta, to Steele City, Nebraska, ultimately carrying 830,000 barrels of oil every day. In June 2013, President Obama said he would let the project go on "if it does not significantly exacerbate the problem of carbon pollution."