This week, The New York Times published two much-needed articles questioning the value of programs that let consumers pay a small fee to ostensibly reduce their carbon footprints.

The first, by Kate Galbraith, focused on renewable energy certificates, which allow utilities to offer their customers the choice of paying a small premium on their electricity bills for clean energy from wind or solar.

“About a quarter of the country’s utilities offer green power programs, and the way they are structured varies,” Galbraith reported:

In practice, no big utility delivers 100 percent renewable power to any customer, since electricity from all sources — coal plants, wind farms, solar panels — is mingled in the same wires. The utilities are essentially collecting extra money that they promise to use to support the development of renewable energy, a pitch that some customers find persuasive.

But a key question—“Do these programs really cause more renewable energy projects to get built?”—remains unanswered, Galbraith found. While some think the trade in renewable energy certificates makes clean-energy cost competitive, others think it’s just a waste of money. An audit of a cancelled green power program in Florida, for instance, found that “the vast majority of homeowners’ payments went into marketing and administration.”

The second Times article casting doubt on voluntary carbon-reduction schemes, by Elisabeth Rosenthal, focused on carbon offsets—specifically those offered by airlines. In theory, the small, extras fees paid by guilty-feeling passengers go toward tree planting or hydropower projects that reduce greenhouse-gas emissions.

“Offsets have played a growing role in the greening of travel because carbon dioxide emissions from airplanes are growing so quickly and there is currently no technological fix that would drastically lower them,” Rosenthal reported. “But it has proved difficult to monitor or quantify the emissions-reducing potential of the thousands of green projects financed by customers’ payments, and there are no industrywide standards.”

For that reason, Responsible Travel, one of the first travel companies to offer customers the option of buying offsets, cancelled its program this year. Likewise, groups like Yahoo and the U.S. House of Representatives have stopped buying them. Even Paul Dickenson, chief executive of the Carbon Disclosure Project, a consortium of companies that have pledged to report and reduce their emissions, told Rosenthal that he’s not biting. Dickenson would prefer that consumers actually reduce their air travel instead, by taking trains or conducting meetings by phone or teleconference.

Rosenthal’s article ends with a somewhat suspect quote from Dickenson, however. Referring to Warren Buffett’s recent purchase of Burlington Northern Santa Fe railroad, he said, “What does it tell you that the world’s most successful investor is investing in trains?”

Well, most analysts seem to think that Buffett’s investment tells us that he’s betting big on the future of coal. According to The Wall Street Journal, “Burlington Northern carries coal that generates about 10% of all U.S. electricity,” and coal shipments accounted for almost a quarter of the company’s freight revenue last year.

Despite that awkward conclusion, however, both Rosenthal’s article and Galbraith’s are the kind that we hope to see more of in the coming weeks, months, and years. Renewable energy certificates and carbon offsets are just two of the sketchy financial products emerging from the burgeoning global carbon market. Unregulated, they threaten to discredit the very idea of sustainable commerce.

Curtis Brainard is the editor of The Observatory, CJR's online critique of science and environment reporting. Follow him on Twitter @cbrainard.