If previously developed oil, gas and coal reserves are exhausted, the Earth could be pushed well past the threshold for dangerous climate change, according to a report published Thursday.
Fossil fuels from active fields and mines allowed to operate through their projected lifetimes would punch through the 2-degree-Celsius cap for global warming laid out in the Paris Agreement based on industry data, according to the report.
The analysis by Oil Change International was released one day after world leaders gathered in New York to speed up the process of bringing the global climate pact, signed by 195 nations in December, into force.
That is likely to happen before the end of the year, U.N. Secretary-General Ban Ki-moon said Wednesday.
With the impacts of climate change - which include heat waves, deadly flooding and storm surges fueled by rising sea levels - being felt earlier and more severely than predicted, world leaders are under growing pressure to accelerate the transition away from carbon-intensive fossil fuels.
The coal industry has been hit the hardest, with moratoriums on new plants put in place this year in China and Indonesia, along with one covering federal land in the U.S.
The Paris Agreement calls for maintaining global warming at "well below" the two-degree Celsius (3.6 degrees Fahrenheit) level, compared to pre-Industrial Revolution levels, and under 1.5 degrees Celsius (2.7 degrees Fahrenheit) if possible.
Even without coal, the existing reserves of oil and gas alone would be enough to breach the 1.5 degrees Celsius barrier, according to the 60-page report.
"If the world is serious about achieving the goals agreed upon in Paris, governments have to stop the expansion of the fossil fuel industry," said Stephen Kretzmann, executive director of Oil Change International.
Of the 200 climate scientists who gathered in Oxford, England this week at a conference on the more stringent climate change goal, many said that staying under the 1.5 degree Celsius level may be out of reach.
The planet's temperature has already increased by 1.0 degrees Celsius (1.8 Fahrenheit), and could see its first year above 1.5 degrees Celsius "within a decade," said Richard Betts, head of climate impacts research at the Met Office Hadley Center in England.
The new analysis compares the projected emissions of burning fossil fuels from current operations to the carbon "budget" -- the sum total of CO-2 that can be emitted without exceeding the 2C limit.
Scientists calculate the Earth's threshold as less than 1,000 billion tons of CO2.
Previous studies regarding these limits have focused more on the consumption of oil, gas and coal rather than the potential for supply.
"Once an extraction operation is underway, it creates an incentive to continue so as to recoup investment and create profits," the lead author of the report Greg Muttitt said.
"This is how carbon emissions get 'locked in,'" he added.
Projected investment in new fields, mines and transportation infrastructure over the next 20 years is $14 trillion (12.5 trillion euros), according to industry figures.
Some of the biggest projects in the pipeline are in the U.S., Canada, Australia, India, Russia, Qatar and Iran.
For coal - the dirtiest and most carbon-polluting of the major fossil fuels - two countries, Australia and India, are moving forward with new, large-scale mining development.
In 2015, India set a target to triple the national coal extraction level to 1.5 billion tons per year by 2020, though some commentators say the country will be hard put to reach that goal.
Historically, India has not been a major contributor to climate change, and even today its population - on a per capita basis - produces far less carbon pollution than Western nations, or even China.
The report's findings were based on data from Rystad Energy, a leading oil and gas consultancy.