The Tar Sands are the most environmentally devastating project on earth, involving extracting oil from a mix of clay and other materials, from underneath Canada’s Boreal forest. The refining process is complex and very energy intensive.

TransCanada, one of the largest companies involved in tar sands exploration, has proposed a 1,661 mile, 36-inch extension of the newly built Keystone Pipeline from Alberta, Canada to oil refineries of the United States. This would expand the capacity for refining oil produced from Alberta tar sands by approximately one million barrels per day.

Bill McKibben, Naomi Klein, James Hansen et al write:

As you know, the planet is steadily warming: 2010 was the warmest year on record, and we’ve seen the resulting chaos in almost every corner of the earth.

And as you also know, our democracy is increasingly controlled by special interests interested only in their short-term profit.

These two trends collide this summer in Washington, where the State Department and the White House have to decide whether to grant a certificate of ‘national interest’ to some of the biggest fossil fuel players on earth. These corporations want to build the so-called ‘Keystone XL Pipeline’ from Canada’s tar sands to Texas refineries.

To call this project a horror is serious understatement. The tar sands have wrecked huge parts of Alberta, disrupting ways of life in indigenous communities—First Nations communities in Canada, and tribes along the pipeline route in the U.S. have demanded the destruction cease. The pipeline crosses crucial areas like the Oglalla Aquifer where a spill would be disastrous—and though the pipeline companies insist they are using ‘state of the art’ technologies that should leak only once every 7 years, the precursor pipeline and its pumping stations have leaked a dozen times in the past year. These local impacts alone would be cause enough to block such a plan. But the Keystone Pipeline would also be a fifteen hundred mile fuse to the biggest carbon bomb on the continent, a way to make it easier and faster to trigger the final overheating of our planet, the one place to which we are all indigenous.

How much carbon lies in the recoverable tar sands of Alberta? A recent calculation from some of our foremost scientists puts the figure at about 200 parts per million. Even with the new pipeline they won’t be able to burn that much overnight—but each development like this makes it easier to get more oil out. As the climatologist Jim Hansen (one of the signatories to this letter) explained, if we have any chance of getting back to a stable climate “the principal requirement is that coal emissions must be phased out by 2030 and unconventional fossil fuels, such as tar sands, must be left in the ground.” In other words, he added, “if the tar sands are thrown into the mix it is essentially game over.” The Keystone pipeline is an essential part of the game.