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From a scientific point of view, burning all of the world's proven fossil fuel reserves isn't an option, the paper suggested. The reserves "vastly exceed the allowable CO2 emission budget for staying below 2C" of warming, it said.

In 2009, the findings were used by the International Energy Agency (IEA), a policy group that advises 28 countries about their energy policies, to make the case for steep reductions in climate-changing gases. "We are currently eating into these CO2 budgets at a disproportionate rate," the authors wrote in its World Energy Outlook that year.

Less than four years later, the paper is one the most cited environmental science studies ever. To date, it has garnered 262 citations in scientific articles, according to Web of Science, an online citation index run by media conglomerate Thomson Reuters, putting it in the top 0.1 percent cited environmental papers in recent years, and just missing being among the top 0.01 percent. The paper has racked up more than 600 citations in Google Scholar, a more inclusive citation index that includes mentions in books, professional societies and on university websites.

Christopher King, editorial content manager of Thomson Reuters' ScienceWatch, a site that tracks trends in research, said it "unquestionably ranks among the elite."

In science, that many citations reflects a rare consensus, according to Gavin Schmidt, deputy chief of the NASA Goddard Institute for Space Studies and a climate modeler. He said that while a few minor details in the paper have raised discussion, such as the fact that the model doesn't account for short-lived gases like methane, the overall results are widely accepted.

After impressing scientists, it wasn't long before the findings rippled through the global financial world.

For years, investors had been hearing of carbon budgets and the 2-degree threshold - and they were growing concerned. As much as 30 percent of the value of some of the world's stock exchanges is in proven coal, oil and gas reserves, which energy companies are banking on mining and selling one day.

But what if governments buckled to activist pressure and decided to require firms to keep some of those reserves in the ground? What would that do to the market values of powerful energy companies? What would that do to the world's financial systems?

A newly formed group, made up of green-minded investors in London and called the Carbon Tracker Initiative, sought to assess those risks in a scientific way. They used Meinshausen's paper as the basis of their own report, "Unburnable Carbon," published in 2011.

The report tackled a question that Meinshausen had answered, but not in any depth: How much CO2 is in the world's fossil fuel reserves?

Using official records from U.S. Securities and Exchange Commission filings, among other documents, Carbon Tracker discovered that the world's top 200 fossil fuel companies have 2,795 gigatons of CO2 trapped in their fossil fuel reserves. And that figure didn't include unconventional sources like tar sands, oil shale and methane hydrates.

They also found that in the first 10 years of this century, humans had burned through one-third of Meinhausen's 886-gigaton budget, leaving just 565 gigatons left to use over the next 40 years. In sum, 80 percent of all fossil fuel reserves would have to remain untouched to prevent uncontrollable warming, the report warned.