Former President Jimmy Carter on Wednesday announced his opposition to the Keystone XL pipeline, joining a group of Nobel laureates urging President Barack Obama to reject the project.
In a letter to Obama and Secretary of State John Kerry, Carter and nine other Nobel Peace Prize recipients said the decision on whether to approve the pipeline would be one of the administration's most critical choices.
"You stand on the brink of making a choice that will define your legacy on one of the greatest challenges humanity has ever faced -- climate change," reads the letter. "As you deliberate the Keystone XL tar sands pipeline, you are poised to make a decision that will signal either a dangerous commitment to the status quo, or bold leadership that will inspire millions counting on you to do the right thing for our shared climate."
Carter is the first former president to come out against the controversial pipeline, which would export crude oil from tar sands in Canada to refineries in the United States. The portion of the pipeline pending State Department approval would span 1,179 miles.
Last year, former president George W. Bush described the project as a "no-brainer."
"If private sector growth is the goal and Keystone pipeline creates 20,000 new private sector jobs, build the damn thing," he said.
Environmental groups, however, have warned of the enormous impact the project could have on the climate.
Obama is expected to make a decision on the pipeline sometime this year.
"History will reflect on this moment and it will be clear to our children and grandchildren if you made the right choice," the letter reads. "A rejection would signal a new course for the world's largest economy. You know as well as we do the powerful precedent that this would set."
Read the full letter below: