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More than 25 years ago, I made a curious discovery about trash, thanks to some obscure data published by the U.S. government. The data indicated that what is commonly referred to as municipal solid waste (MSW) — consisting of "everyday items we use and then throw away," according to the Environmental Protection Agency — was only a tiny fraction of the overall waste picture.

Indeed, MSW, which includes newspapers, cardboard, yard clippings, bottles and cans and various other things people toss out, represents less than 2 percent of the bigger picture — what I dubbed Gross National Trash, or GNT.

You can see it in the graphic below. The entire circle on the left represents a mere sliver of the circle on the right. GNT includes the daily detritus of our industrial world — the emissions, effluents, dregs and debris created by business.

The numbers, from 1992, seemed to be a one-off calculation, not one of those government data sets that are regularly updated. Ten years ago, I was able to update the data, which didn’t change the overall percentages, although some numbers swung so wildly that the whole data set became suspect.

As I concluded in 2009: "The government — and the rest of us — don't have a clue about how much waste companies produce."

Now, the data sets have been updated again. And, once again, the numbers are similar — and similarly suspect. The implications of so many unknowns when it comes to waste represent a conundrum for the emerging circular economy: If we can’t accurately measure our waste, how can we manage it?

To understand the problem, it helps to understand the bigger picture. The GNT pie includes five major slices:

• The biggest slice consists of industrial wastes from pulp and paper, iron and steel, stone, clay, glass, concrete, food processing, textile manufacturing, plastics and resins manufacturing, chemical manufacturing, water treatment and other industries and processes. All of it results from fabricating, synthesizing, modeling, molding, extruding, welding, forging, distilling, purifying, refining and otherwise concocting what are collectively referred to as the finished and semi-finished materials of our manufactured world.
• A slightly smaller slice is something called RCRA special waste, referring to a category of wastes defined under the U.S. Resource Conservation and Recovery Act of 1976. This includes medical waste, septic tank pumpings, industrial process waste, slaughterhouse waste, pesticide containers, incinerator ash and other things.
• A third slice is mining waste such as mine dumps, culm dumps, slimes, tailings, leach residue, slickens and all the other terms to describe the stuff that comes out of a mine that has no commercial value.
• A fourth slice consists of hazardous waste, a witch’s brew of toxic ingredients found in paints, pesticides, printing ink and chemicals used in hundreds of manufacturing processes — nearly 500 such substances, from acetonitrile (CH₃CN) to ziram (C₆H₁₂N₂S₄Zn).
• The final slice of the pie, a minuscule sliver of the whole, is municipal solid waste — the entire circle on the left.

As I said, some of this data is suspect. And it turns out that I’m not the only one who’s been trying to understand exactly what U.S. businesses and industries are discarding. I was recently directed to an article by Max Liboiron, an assistant professor of geography at Memorial University of Newfoundland.

Dr. Liboiron had been chasing a similar story — she cites the earliest data from 1987, not 1992 — which showed that MSW comprised just 3 percent of GNT (my term, not hers), more than I'd calculated but relatively the same small slice.

She called the 3 percent number "shady," in part because much of the waste was self-reported by industry. "Almost all of this waste is interred onsite without permit or public knowledge on the industrial property where it was generated," Liboiron noted. Being the good academic, she cites — and also debunks — other research studies that came up with roughly the same 97-to-3 GNT-MSW ratio.

In the end, Dr. Liboiron seemed as perplexed as I was more than two decades ago:

"In short, we do not have an idea of the quantity of non-household solid waste produced in North America. When we do have ideas of (sub)quantities, we do not have good classifications, so we do not know what we are quantifying. The 97-3 ratio might be okay to use as an illustrative point of relative scale, but since modern waste is characterized by extreme tonnage, toxicity and heterogeneity, then we have no reliable data on any of the three things that characterize most waste produced in North America."

Why does all this matter? It’s not just academic.

As we increasingly explore, design and implement business strategies that can lead to circular systems of commerce, it will be ever more important to understand where we are. That means we’ll need solid baselines from which to set ambitious goals and to measure progress. We’ll need a better accounting of the wastes produced at every stage of mining, harvesting, manufacturing, customer use and whatever we eventually rename "end of life," since that concept theoretically will disappear in a circular world.

Without good metrics, we’ll be unable to set policies or assess corporate commitments and achievements. We’ll risk being unable to adequately address resource use efficiency at the scale needed to produce the goods demanded by the billion individuals soon to be knocking on the door of the middle class. We’ll claim progress without any reasonable understanding of whether we’re actually making any.

That could lead to the circular economy becoming just another meaningless buzzword, if not greenwash. And that would truly be a waste.