Not since King Kong vs. Godzilla have we seen a monster fight of this magnitude. Disaster vs. Disaster, Category I Apocalypse vs. Category I Apocalypse. Best of all, NASA’s James Hansen serves as referee.

In the first corner, we have Peak Oil, the premise that we’ll soon (or perhaps already) have reached the maximum production of petroleum, and that remaining reserves are far lower than generally acknowledged. The result: ever-rising fuel prices, and possibly even social and economic collapse if peak oil hits faster and harder than expected. Even the moderate-case scenarios show declining petroleum access by the 2020s—and all while China and India are ramping up a car economy.

In the second corner, we have Global Warming, the result of greenhouse gases—particularly CO2 from human sources, such as burning petroleum—trapping heat in the atmosphere. We’re now at 385 parts-per-million and rising (up from 284ppm in the pre-industrial era). Climatologists generally consider 450ppm a tipping point into unrecoverable disaster, although there are now some signs that the already-past 350ppm would be a safer maximum. Among the actions required to avoid global warming disaster: a dramatic reduction in the consumption of fossil fuels.

In the latest Intergovernmental Panel on Climate Change (IPCC) report, the “business-as-usual” scenario, which posits that society keeps going as it has, and fossil fuel consumption continues to grow at its current pace, results in an atmospheric CO2 concentration of over 950ppm by the end of this century. It won’t happen, of course—the effects of global warming (sea level rise, drought, pandemic disease, dogs and cats living together, etc.) would make such steady growth untenable. Technology change would play a role, too, as would shifts in population. But the biggest reason why it won’t happen is a simple one:

There isn’t enough petroleum in the ground, in any form, to make it possible.