04/22/2013 05:19 pm ET Updated Jun 22, 2013

Earth Day vs. Tar Sands

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If you love the Earth, you need to know some things about tar sands crude -- starting with how it would affect the climate of this wonderful planet we all share. Actually, "affect" is probably the wrong word. We're talking wholesale destruction.

A just-released report from Oil Change International, "Cooking the Books," shows that the carbon emissions from the Keystone XL pipeline alone would be enough to undermine most of the progress that we've made to date on limiting climate-disrupting carbon pollution. If approved, the Keystone XL tar sands pipeline would be responsible for the carbon-pollution equivalent of more than 37.7 million cars -- every single year. Between 2015 and 2050, Keystone XL's emissions would add up to more carbon pollution than the entire United States produced during 2011.

I'm an optimist. The strong fuel-economy standards from the Obama administration and the steady move away from coal-fired power plants have us heading, slowly, in the right direction. It's easy to be inspired by sights like last weekend's 16-mile march by the Moapa Band of Paiutes of southern Nevada from the polluting Reid Gardner coal plant to the site of their soon-to-be-built solar project, which will be the largest on tribal lands in the U.S.

Keystone XL, however, threatens to derail this kind of clean-energy progress with one stroke.

The State Department has asserted that the pipeline would result in "no substantive change in global greenhouse gas emissions." How did the State Department get it so wrong? Simple -- it assumed that Canada's tar sands will be developed regardless of whether Keystone XL is built. Talk about self-defeating, circular logic.

The truth is that we cannot afford to do anything that will make it easier for Big Oil to extract the tar sands, and Keystone XL certainly fits that bill. If it didn't, then its proponents would not be fighting so hard to get it built. The tar sands are not a path to energy independence -- they're a fast track to climate disaster.

Here's another important reason why Keystone XL must be stopped: The appalling risk it poses to the American people. The 22-foot gash in ExxonMobil's Pegasus tar sands pipeline in Arkansas puts that risk in sharp relief.

Here's how Riki Ott, a marine toxicologist and oil-spill health expert, explained the difference between tar sands crude and conventional oil to me:

Tar sands crude contains much higher concentrations of the ultrafine particles, or polycyclic aromatic hydrocarbons (PAHs), which are the long-term bad actors in terms of health issues. PAHs get inside cells and jam cell function, causing respiratory problems, reproductive problems, depressing immune system function, disrupting DNA coding, and more.

Tar sands bitumen contains 11 times more heavy metal than conventional oil, which is bad enough, but to make it possible to pump the sludgy bitumen, it must be mixed with another hydrocarbon, usually a natural gas distillate. When a tar sands spill happens, the distillate vaporizes, releasing toxic chemicals into the air. And if the heavy bitumen that's left behind gets into the water, it doesn't float like conventional oil -- it sinks.

In spite of the particular danger posed by a tar sands spill, no proven protocol exists for cleaning one up. We don't even know whether it's even possible to completely clean one up. Almost three years and a billion dollars after the tar-sands disaster that contaminated Michigan's Kalamazoo River, there is still bitumen on the riverbed.

Every day, more Americans become aware of just how extreme and dangerous a fuel tar sands crude really is. Last week, at the only public hearing on Keystone XL that the State Department will hold, hundreds of people testified about the pipeline. According to the New York Times, though, those who spoke out against it outnumbered proponents by at least 12 to 1.

President Obama cannot use ignorance as an excuse. He cannot approve Keystone XL and still claim to be moving forward on climate. As the Oil Change International report makes clear, he would in fact be cancelling out much of the progress on climate disruption that his administration has already achieved.

Today is Earth Day. Today is also the last day you can submit your comment to President Obama and the State Department. Do it now, please.