Almost exactly a decade ago, as the Federal Reserve worked to stabilize a careening stock market, overleveraged banks, and underwater mortgage lenders, it made a decision that helped fundamentally reshape the global energy industry. In the middle of October 2008, the Fed agreed to bail out America’s big banks, even the ones that weren’t failing, like JP Morgan Chase, Citigroup, and Goldman Sachs.

That decision continues to be hotly debated ten years later. But its profound environmental impacts are, quite often, overlooked. The bailout was one of the most significant turning points in America’s role in the global climate crisis and perhaps its most important piece of environmental legislation, ushering in a decade of fossil fuel investment that has set the fight to curb carbon emissions globally back decades.

Before America’s housing market collapsed in 2008, its fossil fuel sector had been in a period of lengthy decline. Domestic oil and gas wells had stagnated through much of the 2000s; production flatlined at around five million barrels, and many experts warned that shortages could be imminent. That began to change at around the time of the financial crisis. In 2007, a group of oil industry veterans, scientists, and private equity investors presented their findings at a conference put on by Goldman Sachs. Mark Papa, the head of EOG Resources (short for Enron Oil Group, an independent entity established in the wake of Enron’s 2001 collapse), was there to sell investors on a new technology pioneered by Texas oilman George Mitchell in the late 1990s and early 2000s: hydraulic fracking.

EOG, an early adopter, believed it had identified a vast swath of shale formations that could be fracked, and before too long, investors bought in. By 2008, the financial crisis was in full swing. With oil prices spiking, banks, seeking a sure bet, saw in fracking a tempting investment opportunity. The financials were somewhat shaky—at that point, shale companies had been losing hundreds of millions of dollars trying to make the technology work and scale it out. Many would have folded if not for the massive and sustained financial backing that Wall Street, riding a recent infusion of taxpayer money after the bailout, was willing to provide.

Even as oil prices dropped, investment continued. “Those companies paid good dividends,” said David Hughes, a fellow at the Post Carbon Institute. “They weren’t profitable, but if you don’t have any other place to put your money because of low interest rates, it isn’t hard to find investors.” So Wall Street banks took the money the Fed had lent them and plowed it straight into the fossil fuel industry. In recent years, bailout recipients JP Morgan Chase and Citigroup loaned over $900 million and $600 million respectively to EOG alone (it’s hard to know if every last dollar went into the company’s fracking infrastructure, but it’s likely the overwhelming majority did). Each time shale driller Halcon came close to violating debt limits set by its backers, the company’s lenders—JP Morgan Chase and Wells Fargo—loosened restrictions. Oil that according to pure market forces might have otherwise stayed in the ground continued to flow.