The global energy map is undergoing a dramatic transformation. Oil production is now increasing rapidly in North America, reversing a steady decline since the 1970s. Easily accessible fossil fuels are mostly gone, causing the industry to now go to unprecedented lengths to extract oil and gas that was previously considered too dirty, inaccessible, or unprofitable—as exemplified by tar sands, fracking, and deepwater drilling. With its tar sands deposits, referred to by the industry as oil sands, Canada has the third largest proven oil reserves in the world. By 2017, the International Energy Agency projects that the U.S. will become the world’s largest oil producer.

First proposed in 2008, the Keystone XL pipeline is a seven billion dollar project that is slated to transport tar sands oil from Alberta, Canada, across six U.S. states to refineries on the Texas Gulf Coast. Opposition to the pipeline has stemmed from a wide variety of concerns, from property rights and indigenous rights, to water quality and ecological destruction. Tar sands, which contain an extremely viscous form of petroleum known as bitumen, require large amounts of energy and water for extraction, transport, and refining. Extraction involves clear-cutting Canada’s boreal forest, and transporting the bitumen requires dilution with other petrochemicals. Yet the most fervent and controversial reason many people oppose tar sands is that its exploitation will release massive amounts of carbon dioxide into the atmosphere and further disrupt the Earth’s climate, while diverting attention and resources away from low-impact, renewable, domestic energy. James Hansen, director of the NASA Goddard Institute for Space Studies, calls this scenario “game over for the climate.” For these reasons, environmental groups specifically targeted the Keystone XL pipeline and created a campaign of civil disobedience to stop its construction.

In 2011, the fight against the Keystone XL pipeline became the most visible fight in the American environmental movement when over 1,200 people were arrested in front of the White House. A few months later, 12,000 people formed a ring around the White House to urge President Obama to reject the pipeline’s permits. The president delayed his decision until 2013, citing the need for a more thorough environmental review. Last March, however, the president fast-tracked the southern leg of the Keystone XL pipeline, which runs from Oklahoma to Texas. Construction of the southern leg began in August of 2012, and the pipe is now in the ground. This spring, President Obama is expected to make a determination on the northern segment, and many feel that his decision will define the administration’s commitment to addressing climate change.

Proponents of the Keystone XL pipeline argue that exploiting Canadian tar sands will increase North American energy independence and create jobs, although critics have responded the oil will likely be exported on the global energy market and may destroy more jobs than it generates. Regardless, the world’s leading climate scientists maintain that continuing to burn fossil fuels at anywhere near current rates will have disastrous consequences for life on our planet. North America is now ground zero in a brewing climate war that pits a domestic energy boom against the stability of the global climate. The Keystone XL pipeline has become a potent symbol of that conflict and everything that hangs in the balance.