Keystone XL is a proposed pipeline that would transport 800,000 barrels/day of the world's dirtiest oil (tar sands) from the forests of Canada across America to the Gulf Coast, risking the water & health of communities along the way. The carbon emissions would equal 40 million cars or 50 coal-fired power plants each year. This "carbon bomb" could lock us on a path toward catastrophic climate change and is exactly the type of extreme dirty energy we must reject to change course.