Most world leaders have left Glasgow. But the U.N. Climate Change Conference goes on in Scotland, with thousands of delegates diligently working out the next steps to mitigate global warming.

Yet what if the data delegates are negotiating over isn't honest — either intentionally or unintentionally?

That's the provocative — and profound, given the stakes — question raised by a Washington Post investigation published Monday. With clarity that emissions reports from nations sorely lack, the Post starkly states: "The plan to save the world from the worst of climate change is built on data. But the data the world is relying on is inaccurate."

How inaccurate? The Post examined 196 reports and found a "giant gap between what nations declare their emissions to be verses the greenhouse gases they are sending into the atmosphere."

The gap — a gulf, really — ranges from 8.5 to 13.3 billion tons a year of unreported emissions, which the Post reports is "big enough to move the needle on how much the Earth will warm."

In just one example, the Post examines reporting from Malaysia. The nation claims that trees are absorbing carbon four times faster than those in neighboring Indonesia, resulting in a "slashing of 73% of emissions from its bottom line." Using U.N. data from 2016, Malaysia released 422 million tons of greenhouse gases, putting it in the top 25 emitters. But its claim about trees reduced that figure to only 81 million tons, less than that of much smaller Belgium.

The culprit for 59% of the misreporting, the Post wrote, is due to how nations calculate emissions from land, a "unique sector in that it can both help and harm the climate." Land can indeed draw in carbon as plants grow and soil stores it. Or, of course, it can be released in the atmosphere as forests are logged or other extraction occurs. Some of this misreporting is due to sketchy accounting, as with Malaysia, and some is allowed under current U.N. reporting rules, particularly in large nations such as China, Russia and the U.S.

Many nations, the Post reported, inaccurately claim that carbon emissions are offset by land absorption, distorting the data and rendering comparisons commensurately skewed. (Methane emissions are the second most significant factor.)

"This is definitely an argument focusing on emissions in U.N. accounting, or at least separating emissions from sequestration. That allows a better apples-to-apples comparison," Prof. Jessica Hellmann, director of the University of Minnesota's Institute on the Environment, told an editorial writer in an e-mail exchange.

"We really need independent validation from satellite observations and other techniques," Hellmann said. (And in fact, the Post in part used satellite technology to get a better metric on emissions.) "That validation can be at the national level but also at the level of individual emitters (companies, farmers, urban areas, etc.)."

The good news, Hellmann added, is that "we should see an explosion of new data coming on the scene in the coming years."

But in the meantime, such data discrepancies risk eroding the trust needed to convince citizens, especially in responsive democracies, to make necessary sacrifices. And it adds to an already roiling global debate between developed and developing countries about the unequal impact and origination of global warming.

Climate change is an existential threat to every nation, and by extension every person. The world must act now to avoid the worst. And it must have an accurate accounting of the extent of the problem and the extent of any progress in fighting it.