11/30/2015 04:56 pm ET Updated Nov 30, 2016

Going Into Paris Talks, the U.S. and China Collude to Gobble Up the Global Carbon Pie

By Anukriti and Alexander Hittle

Note: This commentary first appeared in The Honolulu Star Advertiser on Nov 29, 2015.

For spectators who are keeping score at the Paris global climate talks starting this week, the number that should be circled is 900 billion. The units? Not dollars, but billions of tons of carbon dioxide. Why 900 billion? That is the amount of carbon dioxide the U.N.'s scientific review says that humanity can emit and still achieve the widely accepted target of keeping global temperature rise below 2 degrees Celsius.

The politics in Paris will be all about who gets to emit the 900 billion tons in the global carbon budget - how will the world divide up that carbon pie?

Our latest paper concludes that China and the U.S. have staked out, ahead of Paris, a carbon claim so large that they may crowd out the rest of the world's chances to develop and prosper.

Going into Paris the two emissions giants have made the following commitments: the U.S. promises to cut emissions from 2005 levels by 26%-28% by 2025, while China has promised only to decrease the carbon intensity of its economy by 60-65% between now and 2030 and then stabilize its emissions.

Although large U.S. cuts in exchange for distant Chinese stabilization look appallingly lopsided, the deal is consistent with notions of carbon 'justice.' The Chinese are simply waiting until per capita emissions and wealth are roughly comparable to that of the U.S. before taking meaningful climate change action.

If notions of justice should apply globally, the deal appears greedy. A simple growth model indicates that by 2050 the U.S. and China will, together, have laid claim to about half the carbon pie--435 billion tons by 2050. This gets a little better if we assume that China peaks rather than stabilizes in 2030, in which case, we estimate the two countries will emit about 370 billion tons, or about 40% of the 900 billion ton limit, by 2050.

So, only two countries comprising 20% of the world's population will consume 40% of the carbon pie. Is this good news? China and the U.S. seem to be pleased with it. They look like the good guys even as they collude to pollute.

But even under the most optimistic scenario, where Chinese emissions peak in 2030, we estimate that the rest of the world would need to begin cutting emissions by about 2% per year starting right now if that 900 billion ton budget is to remain intact through 2050.

It comes as no surprise then that the rest of the world is refusing to play along. A recent U.N. summary of the world's commitments coming into Paris projects total global emissions of roughly 750 billion tons by 2030 and an annual carbon dioxide run rate of around 40 billion tons - simple math points to the 900 billion mark being surpassed around 2035.

As the world jets into Paris to address the problem of global warming, keep in mind that "historic" announcements have already been made - and the U.S. and China have put everyone else on notice that they intend to send more than their fair share up the carbon chute. The rest of the world, meanwhile, has made it clear it will not sacrifice its growth and development prospects on behalf of what historian Niall Ferguson calls "Chimerica."

The recent terror attacks may push nations into agreeing to reduce emissions to send the signal that Paris is an important city--but how equitable will those reductions be remains to be seen.

So, scribble '900' on your scorecard, sit back, and don't hold your breath.

Anukriti Hittle (International Affairs) and Alexander Hittle (Economics) are instructors at Washington University in St. Louis, Mo., and Anukriti is a visiting scholar at the East-West Center in Hawaii. See their full paper here.